@@12voltvids I have been in radio since the 1970s Think I know a thing or 2 about Electronics. I Sold. PYRAMID products for many years & dealt directly with the manufacturer in NYC. Owned ASTRON power supplies " they Blew up, buzzed & hummed & were not as you say " bullet proof"
@@miguelsalami Welcome to the club. Been licensed for over 40 years. Have an astron running a repeater running 24/7 since 1991. That's 29 years and it still works perfect and it is running hot all the time as the repeater draws 22 amps when it is transmitting and when the rag chewers get on, it in running constantly. I just recently closed it down as I lost my frequency when i was off air due to an antenna failure.
Great fix sir. You drag me to old school days when I was learning bridge rectifiers. Great explanation as always. Looking forward for your further uploads. Regards,
+LearningZone I was going to go into the reason they used a CT transformer and only half the bridge but didn't want to et ahead of my self, but basically it cuts the heat, and that second .6V drop across the second pair of diodes. Better manufactures like Astron would use 2 stud type diodes screwed right into the heat sync + rail (whish would naturally be isolated), or they would make the CT the positive side, and ground one side of the diodes. But then this is a cheap Chinese made power supply. Put in a full wave bridge and only use half of it.
That's what I like about linear supplies, if something fails it is usually a simple fix, I am never surprised by how many times I've found mismatched voltages on fuses. In fact, if it is something that runs more than 32 volts I make a standard practice to check the fuse for that reason.
First the voltage on a fuse means nothing. That is the arc over rating. a 2 amp 32 volt fuse will allow the exact same current through as a 2 amp 250v fuse. The difference is on a 120V circuit the 250v fuse will open, and not arc. The 32v fuse will also open, but there is a good chance that the 32v fuse will arc over. Now on a 12v circuit, both would be acceptable. I like linear supplies because they are simple and reliable, and mostly bulletproof. Well at least the Astron USA made supplies, or the old Marconi, or Lorain systems. Never heard of those? Go visit your local telephone switching office and see some of their old power supplies. I bet some of them have been around for 100 years and still going strong,
''YOUR RIGHT'''''''I HATE SWITCHING SUPPLYS''''''I HAD ONE IN MY ''LABRATORY''''IT WAS SO ''NOISEY''''I GOT RID OF IT & REPLACED IT WITH THE ''OLD'''''RUGGED'''''FIXABLE ''LINEAR'''' POWER SUPPLY''''''''''''' NEVER LOOKED BACK UNTIL '''NOW'''''''''''''THANK YOU SO MUCH'''''''''''''''''''JAMES...OKLAHOMA. 73'S.
Ham radio... I'm in my 70's and the game sure has changed. A ham needs his power supply fixed? We used to have to build power supplies to drive the military surplus gear we scrounged for. I'd build mine on upside down aluminum bake pans. Today, I see Extra Class hams who don't even recognize their own callsigns sent in code and wouldn't know an AC condenser from a diode. Building transmitters and power supplies was child's play - finding heavy enough transformer was the tough part. Building sensitive and selective superhets that didn't drift all over the bench was a challenge, but of course you could always get by with a dozen-part regen even if the bandwidth was wide as Bessie's rear end.
@@12voltvids Yep. What was the difference between CB and Ham forty years ago? It was the licensing. Anyone could buy a CB, but ham licenses didn't grow on trees. There were no cheat sheets for ham exams., for me the nearest FCC testing center was out-of-state, and then there was the morse code requirement you had to both copy and receive. Ham radio predictably became Channel 19 when the requirements for an Amateur license became the same as CB. No more theory thanks to the cheat material and the morse code was done away with. When the requirements of Channel 19 became the same as Ham... Ham became Channel 19, version 2.0. I hear crap daily you'd never hear when Hamming was largely a homebrew project.
I have another identical power supply in the shop awaiting parts. This time there are multiple components in the regulator circuit at fault.Will be posted as soon as it is fixed.
That kind of fullwave rectifier not intended for soldering the terminals. Heating while soldering frequently causing failure. It needs cable connectors. Cheers from Indonesia
In North America, the solderless crimp terminals are referred to as “Fast-On” (automotive industry adopted 50 years ago). 0.25 (1/4) inch commonly used, but 0.187 (3/16) inch seen with smaller switches. == I normally “upgrade” old solder connections to Fast-Ons for the bridge rectifier and front panel illuminated rocker switch.
Proper soldering techniques will not hurt this component, However I do endorse the connector practice if already in place and not used in a corrosive environment.
I have the ps-36kx and it's a bit of a different issue. It was working until I did a brain oops and put a device that drew too much from ps. Now it's in fault mode. I had cover off at the time. No smoke came from anywhere. The fuse is still ok. Caps not swollen. Nothing I heard popped or clicked it just went into beep mode and quit putting out. Do you think it may have fried the 723 regulator or transistors since it doesn't automatically reset? I have both on order but I'm not electronics savvy. What would be the most likely culprit in this scenario? Thanks for your help. Great video!
You can probably fix that DMM display by putting something between the case's clear display cover and the glass of the lcd module, to apply downward pressure on the display module. I fixed my Extech mm560 with a small ball of rodico. All segments working great now for years.
Thanks a lot for the very valuable video. Everytime i hear words like ... normally they are connected like this. Instead this time they have decided to do otherwise my instinctive question is ... why ? Why not act following the common and tested good practice ? there must be a good reason to be different. Thanks again, gino
What would be the issue if you turn on the power supply and it gives off 12V but slowly drops to 0V after about 20-30 seconds? Thank you for any response!!
I fixed a lot of them pyramid supply's over the years. The one like that I put angle aluminum with 2 stud diodes. replaced filters old was leaking. with computer grade had 2n3055 replaced with 2N3771 and installed V130LA20 mov. ben working many years now. oner put small fan on back heatsink. The PS36KX uses outher half bridge to power fan. I have the PS86KX that has stud diodes . The PS52KX has 2 of them bridge diodes . If that goes again put a piece of aluminum under that bridge or fix like I did. last one I fixed liked that came back 3 months later same problem. watch for cheap china parts . I always use UL approved/listed fuses . 73's
schöne interessante Videos, gut erklärt, sehe ich mir gerne an! Haben mir auch schon bei dem einen oder anderen Mal geholfen! Grüße wieder aus Germany!
Thanks for this detailed power supply repair. Can you tell what might have caused the rectifier to blow in the first place? Could it have been something the operator did, or was it something that was getting old and breaking down? Thanks, Tom
+THOMMGB Well considering that I have another one of tehse POS supplies, this one a Pyle (of sh1t perhaps) that has its own demons. I think it is more like Pyramid . Pyle and all those other Chinese supplies are over rated for the componets they put in them, and when an operator sees 25 amps he thinks he can run 25 amps, when in fact it is probably only safe to run 12 to 15 amps. WHereas asn Astron RS35 for example is rated 35 amps peak, 25 continuous. You can run full power 24 hours a day on one of those power supplies. These 22 amp 25 peak pyramids are not designed for that. Just look at the rating, 22/25. Astron rate theirs 25/35 peak for a reason. That is called headroom. A 100 watt radio is going to draw a good 20 amps when transmitting, and like most hams they have more than 1 radio on the supply, in receive, so have a 2M rig hooked up, even if not transmitting it is still drawing a few amps in receive, so now you are pushing it. The supply I have on my bench right now apparently only lasted 4 months before it blew up.
@@12voltvidsI have had a few of that style bridge rectifier fail, I think it is a combination of issues, the conduction angle is not huge so the repetitive peak current is far higher than the load current plus I think that a lot of the bridge rectifiers are deliberately mis labelled. There are a lot of double diode devices that probably would suit the application better.
@@12voltvids, I know that both CBers and Hams have great skills in destroying equipment , however I doubt this is a result of that misuse, at 25a of load the bridge rectifier is going to need to shed about 20w of heat. Relying on a steel chassis to conduct the heat is a bit of a recipe for disaster....
Could it be that those caps you expected to be larger, are smaller because of the way the rectifier and center tap are configured? Each cap only has to take 1/2 the supply compared to the traditional wiring.
i was a jr tech and we had a site w/ a Kennedy tape drive that would not power up on a mainframe. I just stayed quite while the senior techs tried to figure out what was wrong. They were going to order a new power supply and I asked ....did you check the fuse? they said yeah it looked ok. It was a slow acting fuse which can still look good when bad. I asked no i mean did you actually check the fuse. it should show as a short. They turned and looked at me in a very disturbed manor. i said we need to check the fuse. so they got their DVM and the fuse checked as an open. new fuse it powered right up.
Hi boss, i have question if you dont mind, if you have dc regulated power supply 13.8 volts same that one with 50 amps and 23kg of weight and u have psu power supply with 50 amps maybe 1kg kilo of weight, the question is they will output same 50 amps
The linear power supply is heavy because of the big inefficient iron and copper transformer. A modern switch mode transformer can deliver a tremendous amount of current from a very small transformer due to the high efficiency of these high frequency power supplies.
if i use for powering car audio amplifier taht u need a lot of amphers. and the psu is100 amps for example which is better to use for car audio amplifier. thanks in advance.
Thanks for this. Gotta troubleshoot my 20 year old ps-21k. But what's odd, is that mine has the equivalent mbp351 rectifier, and according to my ps-21k schematics, all four taps are connected.
My old 80 amp linear supply worked great..a bit heavy but back in 60's not many had fuses on both output binders...the smoke got out of that trans...what an odor..burnt varnished crapper door on a sailboat. Best trans I could get was a 42 amp..off the ten plate selenium rectifier. Swapped out old electrolytics and sold it for gas during rationing in 1973-74. Good work 12v 73,
Superb as always. Curious - you expected bigger capacitors, are the smaller ones wired in parallel to make up capacitance? Less stress on the caps doing it that method perhaps. Really enjoyed your tutorial with the rectifier, thank you as as always!
is there any way you could get your hand on this one again my scr blew and i gave someone the scr to try to get me a new one and they have lost my part and its been a while so i dont know what it looked like or what the part number was . thanks for your time
LOL @ him pinging you! What amazes me is he's a HAM radio operator - and he cannot fix his own PSU?!?!? Reminds me of a boss I had many years ago, he had a degree in electronics (and I don't), yet he couldn't fix his satellite LNB, or his amplifier. He brought them both into work for me to fix. Go figure!
+GadgetUK164 That's the new era of CB'ers er, HAM operators.I myself am a licensed ham, a 2 letter call, and have had my license since the mid 80's. When I wrote my exam there was basically 3 classes of license, plus endorsements. First was the basic license which gave voice operation above 30MHz, and allowed for morse code operation in the "learner" portions of the band. This test covered mostly regulations, and some technical aspects. The operator was only permitted to use commercial gear, no home brew equipment. Once a ham was proficient in code, he/she could take the code test. 5WPM and 12WPM were the 2 standards, and depending on which test you passed it determined which HF bands that you could operate voice or "phone" as it used to be called. Power was limited for basic license to 200 watts if I remember correctly. The next was the advanced license, which covered the more technical aspects of radio design, and amplifiers ect., and permitted the hams to construct their own radio apparatus including receivers, transmitter and amplifiers. It also could be with or without code. Next there was the digital license, which covered basically all the digital modes. Again the HF portion needed code to operate phone on those bands, but it was OK to operate in digital modes such as RTTY, and CW.Now today, a basic license grants all privileges on all bands. The only restriction is basic license are not permitted to build their own gear, and that includes repairing it. To build or repair transmitting apparatus still requires the more technical advanced license. I look down my nose at the many of the hams out there as I see them as nothing more than CB'ers with a ham call sign now. All one has to do is turn on and listen to a repeater any evening, and you will know what I am talking about. There are a lot of "LIDs" out there and the last thing any respectable ham operator wants to be called is a "Lid" unless that happens to be the letters in your call sign.
+GadgetUK164 If a person has a good memory, they simply memorize the question pools and go for that extra. They're clueless in an electronics discussion. I have a similar PS, I consider this an easy repair. But I'll admit that I was thrown off about that negative connection until he explained it, I usually see TWO DIODES instead of a full wave bridge. 73, Don
+GadgetUK164 If a person has a good memory, they simply memorize the question pools and go for that extra. They're clueless in an electronics discussion. I have a similar PS, I consider this an easy repair. But I'll admit that I was thrown off about that negative connection until he explained it, I usually see TWO DIODES instead of a full wave bridge. 73, Don
I have to admit, I've never seen a earth center tap transformer used like that, but I still would have measured the short on the bridge and just swapped it out! It's nice to learn something new though! =) You are right that with education, you either learn it, or memorize it!
+umajunkcollector Yup, the good ones like the Astron do this. The cheap Chinese ones do it this way. I have another PSU on my bench for another ham, this one is the brand PYLE and it is the identical unit to this, bit no shorted rectifier, this one has a regulation problem, SCR crowbar was shorted, and there will be more parts. Will dig into this shortly.
Nice looking PSU, I use Astron for my radio gear (albeit I'm non-active, have them boxed up) have a 50 & 20 amp, great PSU's, just don't drop them on your toe!
+JacksJunkDotCom I am working on an identical unit, but badged PYLE for another ham that is blowed up real good. 4 big regulator transistors and an SCR to start with. Will pick up the parts on the weekend. Now that that big plasma that had me ripping out my hair is dealt with. Expect a video on that beast soon, as it was a real challenge, and I say that with emphasis on "challenge" as the easy way would have been to replace the logic board, but I wanted to find out what was the cause. I eventually got it going with the blow torch. I mean head gun.
Looking at the schematic diagrams. The Astron and Pyramid PSU's use almost exactly the same circuit design. Its funny because I hear arguments all the time about one being superior to the other...l
It is a full wave bridge. Transformer center tap is ground. One half secondary conducts on positive swing (as other side goes negative) and when the AC reverses the other winding conducts. With a non center tap transformer 4 diodes used for full 2ave bridge. With a center tap tranformer only 2 are used.
@@12voltvids So if one were to not use the center tap and place the secondary across the full bridge, the rectified voltage would essentially be doubled....right? Which the regulation board most likely would not handle.....?
@@Ezzell_ that's right. Unless you used just 1 side and center tap. This way is more efficient though and that's why they do it. Full wave bridge you have 2 diodes in line for each half cycle and. Using a center tapped teavsfienwr just 1 diode so only .7v drop as opposed to 1.4v drop.
This is an old video but I just found it... I hope you're able to respond to my question... I have this exact same power supply and when I turn the voltage up, it starts clicking... Just rapid clicking and I see the voltmeter bouncing up and down a little bit. Any ideas? It doesn't matter if there's a load on it or not I have been unable to take this apart as I no longer have a workbench after my second coma. I would appreciate any tips as I use this power supply for a dual band rig requiring about 8 to 10 amps at 13 volts. Thank you you have a great channel
Greetings: I can relate. The damn beeping was annoying me here. The idiot mentality of the inconsiderate constant sending Msgs is 1 reason I gave up phones many years ago. Now I communicate by Eml. I hate Ppl that constantly bother with update inquiry. I update as it becomes available. If they show up whilst I am working on their unit. I stop and put tools away, or work on something else, informing them " since U think it is more important 4 me 2 talk 2 U I am done working on it 4 now". Most get the hint ' I DO NOT TOLERATE NEbody AROUND ME WHILST I AM WORKING', leave and await my updates. My customers respect that. I diagnose and repair 4 other shops. Most of the time these interuptions occur there.
Hi, Very good video! I have a question about a Tatung power supply I bought on ebay. It is a PS 3336 and it is suppose to put out 60 volts and 2 amps. When I turn it on and turn the volts and amps up it will go the 60 volts but the amps only goes to .16. When I put a load on it the volts drop back to 2 volts and amps stay at .16. I have inspected the boards and I don't find and burned out components. There is a big cap that charges to 72 volts and it is rated at 100 volts so it is fine. The power supply has 1 transistor in the back and it does not heat at all. It has a large transformer and it looks fine. Any ideas what cound be wrong?Regards,Arnold.
Did you charge him extra for "pinging" you while you were working on his power supply..LOL I am surprised that shorted diode did not take out the voltage regulator, I would have assumed being shorted it would pour AC into it.
Why did you think it was the bridge? Typically they fail short. What happens then? I’ve been teaching nearly 40 years. My experience is so different that I could benefit from your thoughts. Why didn’t the electrolytic bulk cap NOT explode? Nuts.
Ive had similar repairs with a 30Amp manson and kenwood supplys, yup the bridge went to silicone heaven, i found a 35A fuse in the holder, why do people do it :-(. Im getting some of your favorite capacitors today, i have a crappy zalman zm750-hp atx supply to bring back to life, its full of evil CapXon capacitors :-(. Fresh from r.s semiconductors im getting panasonic FR and FC series low esr types, i matched the esr and ripple to slighty better that the originals, 1000uf and 470uf 16v, not as good as rubycon or nichicon but they will do very nicely :-D
ua-cam.com/video/WPHwh5Z8tc0/v-deo.html Please watch this one for the Pyle power supply. It is identical to this one, and was in the "buzzer" mode. Failed regulators were the problem, and it triggered the protection crowbar which put a dead short on the output.
I accidentally fed 24VAC to the output of the Pyramid PS26KX and blew something. Now I only get the "PROTECTION"" alarm and no output. I replaced the LM723 IC, but this did not do anything. Do you have any suggestions to get this working again? Any help is appreciated. Thank you!
@@12voltvids Thank you! Based on the schematic and visual of the PCB, I need to replace one LM7812 and one TIP41C. Would you agree? Link to the schematic below: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/www.repeater-builder.com/pyramid/pdfs/PS26KX.pdf
@@12voltvids Thank you! I checked the schematic and PCB, and I see two. LM7812 and a TIP41C. Replacing these two should do if if you had to guess? Thanks again!
I have Dell mini ATX power supply. It fried and I had to test it, so I shorted POWER ON pins and it still did not start up. So I just opened the case and tested diodes, diodes were fine. Just forgot to disconnect power cord and tried to put cover back and I got shocked from the case touching the radiator (common ground). So I found out that all the ground was under 225VAC. After testing continuity I found out that the rectifier bridge IC was shorted. Both + and - were hot 225VAC. After removing rectifier bridge, there is still 40VAC on the + and - side where the bridge connected in circuit, so I guess the 40VAC is coming from the shorted transformer secondary coil.
Doubt that. You are referencing the chassis which is cold ground. You need to connect your meter to the hot ground when working on componets on the primary side.
12voltvids As I said, the ground was hot, somehow L was leaking to the common ground and I got shocked. That was a good lesson to test with screwdriver-lamp first, my body is the "cold ground" in that case and yes, the radiators were full AC Line hot before I desoldered rectifier bridge.
I have a power supply question. I'm sure you know that some microphones require 48V DC phantom power. If an audio interface runs on 12VDC, as many do, how is it possible to produce 48VDC for the microphone when DC won't work through a step-up transformer? Even more confusing, how does a PCM recorder that uses household batteries supply 48VDC phantom power?
+CraigTube They use either a DC-Dc converter or buck converter.A DC-DC converter is essentially an inverter. The 12VDC or battery power is converted to high frequency square wave chopped DC, where it goes through a transformer to step up. Rectified and filtered.A buck converter is basically an oscillator with an inductor, and a diode/capacitor to rectify the higher voltage pulses from the collapsing magnetic field in the indictor. This gets added to the original DC. Buck converters are used for low power applications like phantom power. DV-DC converters for higher current devices such as powering VFD displays, or powering higher voltage circuits.
Hi i have a question i buy a new power supply PS36KX and i only turn on to see if it's work fine but when i move the volts switch do not goes up (do not increase volts ) , and i don't have anything connected to it , that is normal ??? is the first time i use one of this
+Osamah Najjar Those are the voltage regulation transistors.This power supply is a variable voltage so the voltage can be adjusted.The transformer puts out about 20 volts after the rectifier, and the voltage is smoothed out, and regulated by those transistors, and the rest of the current that is not needed is dissipated as heat. So you need several large transistors to cut the raw unregulated voltage down to the desired voltage.
Hello 12voltvids, I have the same power supply with what I think are regulator circuit issues. As soon as powered up the red over current protection LED and beeper are activated. Any chance you will be posting your new video soon?
+Mike C Yes it is up. It is a Pyle power supply and is identical to this. It ha the buzzer and overload alarm going off as you describe. The video shows what happens to that one. 4 transistors on the back of the unit and the scr crowbar.
Fantastic, can you use this power supply to as a bench power supply to work on electronics as you do for repairs? If not what would be the best type of power supply to use as a tech..thank you Merry Christmas.and happy new year.
If you are working on car audio and such then yes absolutely. It is regulated and adjustable from 6 to 15 volts, however is not current limited.Proper bench supplies are a better choice as first they can generally be set between 0 and 30 or 60 volts depending on the model, and they feature full current limiting. So if you know that the circuit should draw 2 amps, you can set the power supply to 2 amps max. That way if you have a dead short you won't do further damage. This one puts out 21 amps, so if there is a fault there will be a much bigger fault if you connect it with no fusing.But then again a proper bench supply costs much more than one of these.When I ran a shop I had a proper bench supply, 0 - 30 volts 0-5 amps.I didn't work on car audio though. For big amplifier repair this would be fine.
I have question: I own PS26KX and wanted to use it just to provide linear power supply to just one audio amp but the fan was too loud. What could happen if disconnect the fan - may amp will draw no more than 1.5A, it is 12V, 18W device.?
Appreciated your video. Hm....YOU MAY HAVE TESTED WITH A LOAD BUT IT IS NOT SHOWN IN THE VIDEO. Can't verify pass transistors and regulator board/filter caps w/o load. I'd load it (somehow) and feel the pass transistor casings for equal thermals? Bet filter caps are lunched.
@@JayN4GO they are probably fine. El caps fail far less than the internet experts say. The odd one fails now and again and switch mode power supplies eat them up pretty good and some bad batches that cropped up in some devices but i have devices that are 40+ years old and still work perfectly. I have an astron rs30 power supply which has not been turned off since new in 1993.
+John Schroeder Those are called nickel press pliers and are used to set 3M Scotchlock IDC connectors. Many people just use pliers, but the problem is pliers don't apply even pressure, and don't set the IDC crimp on properly. They are mostly used in telecom industry, and for splicing network wire ect. You just place them over the insulated wire and crimp them on. They are filled with a moisture displacing gel so they can be used in damp locations. The other gadget is a vintage PCMCIA cellular modem, with the cable for an old Motorola flip phone. Way back in the analog cell and dial up days that allowed an old analog cell phone to connect your computer to a dial up modem. That thing is old as the hills, and probably cost a bloody fortune. The card has a standard telephone jack too to plug in a regular phone line. It is only a 14,400 dial up.
Ham radio addiction withdrawal symptoms! Doesn't he have a car battery and a battery charger kicking around? :D Or does he need a new excuse to get away from the XYL :D
Thanks for the video. But after seeing the waste inside of this power supply, Idk how or if Pyramid is still in business. Using a center tapped, probably 800KVA, transformer that probably cost $100 and only using half the windings (thus half of the current capabilities) for the unit. Versus separating the center tap and making 2 individual 12V windings and wiring them in parallel and using the entire bridge rectifier and adding maybe a few more caps at $0.75 each or just increasing the size of the existing capacitor bank. Extremely wastful design on Pyramids part. IMO
My power supply is bigger than that. Most 100 watt radios will draw close to 20 Amps. Most hams will power up multiple radios with a single power supply so therefore you need a big power supply.
@@12voltvids Last time I used a radio was when I was a child aprox 40 years ago, we called them CB radios in the UK and were widely used. We would hook it to a 3 amp battery charger, could reach hundreds of people in our city. Suppose it a bit different in the US as there's more space & open between homes.
@@PF-gi9vv we had/still have cb radio. Hams refer to it as the chicken band. They operate on the 11 meter band at 27mhz. Ham radio in the HD spectrum has 160 meters 80, 40, 20, 15, 12, 10m which is 28-29 mhz. Of course in different countries they used different frequencies for cb. Here hams always considered it a piece of their band as it was originally part of the ham band and the FCC in the us and doc in canada sliced off a sliver of the band and made a new channelized service for citizens use. Low power with distance restrictions. But that didn't stop us from talking skip when the band opened up every 11 years.
My memory is off. I thought current flowed through the diode in the other direction. Opposite of the diamond shape. I can remember having to remember however a full wave rectifier was wired. But I forgot, lol.
A lot op people are saying the current is flowing positive to negative now. we were taught that current flowed negative to positive why would a proton go to an electron. In a dc circuit
@@fredguitarman3536 oh yeah. Before I took electronics in High School, I believed it went from positive to negative. They told me the opposite was true. So my assumptions were correct before I was "educated". That just makes it more confusing to me, lol. NPN Transistor I named (not put in) meaning the arrow points away from the center. PNP was "put in in". Arrow pointed inward.
+Cruiseomatic Switching psu are noisy. You can try to shield them and use chokes and caps but they are noisy, and kick out lots of harmonics , rfi etc. That's why I stick to linear for my radio gear.
+12voltvids This one runs two peltier type iceboxes, 3 radios, a dtv converter box, lights and misc. gear. A linear the size I need would run hundreds and this one I have was free, lol. It has 55 amps at 14.5. How would I start to "choke" this one? I tried torriods on the in and output. Did nothing.
+Cruiseomatic Yes linear are pricey due to the amount of copper and iron in the transformer. Sorry I can't be more specific on noise reduction on switchers, as I have never tried to eliminate RFI from switching supplies. I run linear for this reason, so I don't have to worry about it. I run 2 Astron 35amp connected in parallel.That gives me 70 amps peek, can run 55 all way long and they don't even get warm.I can run my entire shack on theses.Most of the noise is coming from the transformer on a switcher, as they are typically running in the 60-100KHz range.They throw a ton of RF out.
When I first was licensed, an amateur radio operator needed to be able to demonstrate working knowledge of a radio station. In other words you needed to be able to build a transmitter and receiver. You didn't actually have to build one, but you had to be able to explain how a radio receiver, and transmitter operated. Working knowledge, and if you had that working knowledge, then given the parts you would be able to assemble and test the equipment. You also needed to speak the language of (-- --- .-. ... . / -.-. --- -.. . ) For those wondering what I just said, well it is "morse code" which is something that I learned many years ago, and then promptly forgot due to disuse. Today a ham has to only answer some multiple choice questions about regulations, and operating procedures, and they are granted full privilege. I get asked to work on rigs, but I usually turn them down, just because I don't have the required test equipment. I stick to the AV gear.
If the owner of this power supply watches this Video............You CANNOT rush the repair of high voltage components. You drop it off, shut your Mouth and wait.
+Amy Marie The owner is a very good friend of mine, and believe me I have already slapped him for sticking a 15 amp fuse in place of a 6. He used to do voice over work for me on corporate videos and is a ham, but unlike most hams, he is not a technical guy. He can handle the operation of his radio, and put up antennas ect, but when it comes to the internal workings, well I get the work, and end up doing it for basically free. I charge him for the parts.I have known him for 40+ years.
+Amy Marie Could have been any number of things. Doubt that it was an overload though because that would generally bugger up the regulator transistors. Doubt it was a surge either as that rectifier is rated 600V, and it is running on perhaps 35. Likely just a bad part that ran for awhile and just failed. If it had been an Astron it would have never failed. My astron was kit with 240V when the neutral let go on my shack, and I lost an compressor on my air conditioner, and freezer, and a bunch of other electronics. The astron, all it did was pop the fuse. But then again, Astron are built in the USA and they are bulletproof. You do pay for that quality. They are heavy duty units that can run at rated output 24/7 and not even get warm. I wouldn't try that with this light weight.I should do a show and tell comparing my Astron to this light weight, and you will see the quality difference. This one had tiny little filter caps, my Astron the caps measure about 2" in diameter each, with big screw down lugs on top. It is a thing of beauty.
+Amy Marie Lightning whats that? Been so long since we had a good storm here.We might get 1 or 2 little thunder shower storms a year if we are lucky. No drive a few miles east, into the mountains and that is a different story, or head to Calgary the land of the lightning and some wicked storms.
Just repaired my PS 26KX with this very informative and in-depth repair/tutorial. LOL "Ham buddies", thanks!
That's a huge Transformer! With 22 amp, wow! it will be a great tool for finding shorted components on board.
PYRAMID makes good quality heavy duty power supplies I have used them for over 20 years with great results❗
Until they blow up. Aston makes good power supplies. Bulletproof.
@@12voltvids I have been in radio since the 1970s Think I know a thing or 2 about Electronics. I Sold. PYRAMID products for many years & dealt directly with the manufacturer in NYC. Owned ASTRON power supplies " they Blew up, buzzed & hummed & were not as you say " bullet proof"
@@miguelsalami
Welcome to the club. Been licensed for over 40 years. Have an astron running a repeater running 24/7 since 1991. That's 29 years and it still works perfect and it is running hot all the time as the repeater draws 22 amps when it is transmitting and when the rag chewers get on, it in running constantly. I just recently closed it down as I lost my frequency when i was off air due to an antenna failure.
Great fix sir. You drag me to old school days when I was learning bridge rectifiers. Great explanation as always. Looking forward for your further uploads. Regards,
+LearningZone I was going to go into the reason they used a CT transformer and only half the bridge but didn't want to et ahead of my self, but basically it cuts the heat, and that second .6V drop across the second pair of diodes. Better manufactures like Astron would use 2 stud type diodes screwed right into the heat sync + rail (whish would naturally be isolated), or they would make the CT the positive side, and ground one side of the diodes. But then this is a cheap Chinese made power supply. Put in a full wave bridge and only use half of it.
Thanks for another great video I always learn something from every one
THE go-to PSU for Class-D amps back in the day.
That's what I like about linear supplies, if something fails it is usually a simple fix, I am never surprised by how many times I've found mismatched voltages on fuses. In fact, if it is something that runs more than 32 volts I make a standard practice to check the fuse for that reason.
First the voltage on a fuse means nothing. That is the arc over rating.
a 2 amp 32 volt fuse will allow the exact same current through as a 2 amp 250v fuse.
The difference is on a 120V circuit the 250v fuse will open, and not arc. The 32v fuse will also open, but there is a good chance that the 32v fuse will arc over.
Now on a 12v circuit, both would be acceptable.
I like linear supplies because they are simple and reliable, and mostly bulletproof. Well at least the Astron USA made supplies, or the old Marconi, or Lorain systems.
Never heard of those? Go visit your local telephone switching office and see some of their old power supplies. I bet some of them have been around for 100 years and still going strong,
yeah but linear supplies have a lot of disadvantages, like they can't sense the load and dead short protection.
''YOUR RIGHT'''''''I HATE SWITCHING SUPPLYS''''''I HAD ONE IN MY ''LABRATORY''''IT WAS SO ''NOISEY''''I GOT RID OF IT & REPLACED IT WITH THE ''OLD'''''RUGGED'''''FIXABLE ''LINEAR'''' POWER SUPPLY''''''''''''' NEVER LOOKED BACK UNTIL '''NOW'''''''''''''THANK YOU SO MUCH'''''''''''''''''''JAMES...OKLAHOMA. 73'S.
The switched mode supply in my ham station works like a champ and is (electrically) quiet too.
Ham radio... I'm in my 70's and the game sure has changed. A ham needs his power supply fixed? We used to have to build power supplies to drive the military surplus gear we scrounged for. I'd build mine on upside down aluminum bake pans. Today, I see Extra Class hams who don't even recognize their own callsigns sent in code and wouldn't know an AC condenser from a diode. Building transmitters and power supplies was child's play - finding heavy enough transformer was the tough part. Building sensitive and selective superhets that didn't drift all over the bench was a challenge, but of course you could always get by with a dozen-part regen even if the bandwidth was wide as Bessie's rear end.
Your right. Lots of idiots in the hobby now and even more but jobs. The more i listen the less i want to talk.
@@12voltvids Yep. What was the difference between CB and Ham forty years ago? It was the licensing. Anyone could buy a CB, but ham licenses didn't grow on trees. There were no cheat sheets for ham exams., for me the nearest FCC testing center was out-of-state, and then there was the morse code requirement you had to both copy and receive. Ham radio predictably became Channel 19 when the requirements for an Amateur license became the same as CB. No more theory thanks to the cheat material and the morse code was done away with. When the requirements of Channel 19 became the same as Ham... Ham became Channel 19, version 2.0. I hear crap daily you'd never hear when Hamming was largely a homebrew project.
@@mnpd3 yes I am aware. I got my ticket when code was still a requirement.
I have another identical power supply in the shop awaiting parts. This time there are multiple components in the regulator circuit at fault.Will be posted as soon as it is fixed.
That kind of fullwave rectifier not intended for soldering the terminals. Heating while soldering frequently causing failure. It needs cable connectors.
Cheers from Indonesia
In North America, the solderless crimp terminals are referred to as “Fast-On” (automotive industry adopted 50 years ago).
0.25 (1/4) inch commonly used, but 0.187 (3/16) inch seen with smaller switches.
==
I normally “upgrade” old solder connections to Fast-Ons for the bridge rectifier and front panel illuminated rocker switch.
Proper soldering techniques will not hurt this component, However I do endorse the connector practice if already in place and not used in a corrosive environment.
I have the ps-36kx and it's a bit of a different issue. It was working until I did a brain oops and put a device that drew too much from ps. Now it's in fault mode. I had cover off at the time. No smoke came from anywhere. The fuse is still ok. Caps not swollen. Nothing I heard popped or clicked it just went into beep mode and quit putting out. Do you think it may have fried the 723 regulator or transistors since it doesn't automatically reset? I have both on order but I'm not electronics savvy. What would be the most likely culprit in this scenario? Thanks for your help. Great video!
You can probably fix that DMM display by putting something between the case's clear display cover and the glass of the lcd module, to apply downward pressure on the display module. I fixed my Extech mm560 with a small ball of rodico. All segments working great now for years.
Thanks a lot for the very valuable video. Everytime i hear words like ... normally they are connected like this. Instead this time they have decided to do otherwise my instinctive question is ... why ? Why not act following the common and tested good practice ? there must be a good reason to be different. Thanks again, gino
Dayum got some 80s vibe shit on the intro I like that
What would be the issue if you turn on the power supply and it gives off 12V but slowly drops to 0V after about 20-30 seconds? Thank you for any response!!
Thanks for this. Hope to fix a m8 one next week.
I fixed a lot of them pyramid supply's over the years. The one like that I put angle aluminum with 2 stud diodes. replaced filters old was leaking. with computer grade had 2n3055 replaced with 2N3771 and installed V130LA20 mov. ben working many years now. oner put small fan on back heatsink. The PS36KX uses outher half bridge to power fan. I have the PS86KX that has stud diodes . The PS52KX has 2 of them bridge diodes . If that goes again put a piece of aluminum under that bridge or fix like I did. last one I fixed liked that came back 3 months later same problem. watch for cheap china parts . I always use UL approved/listed fuses . 73's
schöne interessante Videos, gut erklärt, sehe ich mir gerne an! Haben mir auch schon bei dem einen oder anderen Mal geholfen! Grüße wieder aus Germany!
Should have tried the bigger fuse first. The extra pressure can unclog a stuck diode sometimes.
Sounds like a good way to get Schott if things go wrong.
@@RobinDobbie Agreed. Perhaps we should leave these problems for the next Zener-ation.
Hey guys, how about put a 30A in it and watch 4 the smoke. Somewhere near that is Ur problem(s). Idiot ideology.
produces MAXsmoke
Thanks for this detailed power supply repair.
Can you tell what might have caused the rectifier to blow in the first place? Could it have been something the operator did, or was it something that was getting old and breaking down?
Thanks, Tom
+THOMMGB Well considering that I have another one of tehse POS supplies, this one a Pyle (of sh1t perhaps) that has its own demons. I think it is more like Pyramid . Pyle and all those other Chinese supplies are over rated for the componets they put in them, and when an operator sees 25 amps he thinks he can run 25 amps, when in fact it is probably only safe to run 12 to 15 amps. WHereas asn Astron RS35 for example is rated 35 amps peak, 25 continuous. You can run full power 24 hours a day on one of those power supplies. These 22 amp 25 peak pyramids are not designed for that. Just look at the rating, 22/25. Astron rate theirs 25/35 peak for a reason. That is called headroom. A 100 watt radio is going to draw a good 20 amps when transmitting, and like most hams they have more than 1 radio on the supply, in receive, so have a 2M rig hooked up, even if not transmitting it is still drawing a few amps in receive, so now you are pushing it. The supply I have on my bench right now apparently only lasted 4 months before it blew up.
+12voltvids Wow, you are a fountain of knowledge. Thanks a lot. That was a very thorough answer.
@@12voltvidsI have had a few of that style bridge rectifier fail, I think it is a combination of issues, the conduction angle is not huge so the repetitive peak current is far higher than the load current plus I think that a lot of the bridge rectifiers are deliberately mis labelled. There are a lot of double diode devices that probably would suit the application better.
@@g0fvt
Or the user tried to use it as a battery charger and hooked the battery up backwards.
@@12voltvids, I know that both CBers and Hams have great skills in destroying equipment , however I doubt this is a result of that misuse, at 25a of load the bridge rectifier is going to need to shed about 20w of heat. Relying on a steel chassis to conduct the heat is a bit of a recipe for disaster....
Could it be that those caps you expected to be larger, are smaller because of the way the rectifier and center tap are configured? Each cap only has to take 1/2 the supply compared to the traditional wiring.
thanks again for this valuable information.
Where can I find a good supplier of large transformers like found in this power supply?
Hammond manufacturing.www.hammondmfg.com/
i was a jr tech and we had a site w/ a Kennedy tape drive that would not power up on a mainframe. I just stayed quite while the senior techs tried to figure out what was wrong. They were going to order a new power supply and I asked ....did you check the fuse? they said yeah it looked ok. It was a slow acting fuse which can still look good when bad. I asked no i mean did you actually check the fuse. it should show as a short. They turned and looked at me in a very disturbed manor. i said we need to check the fuse. so they got their DVM and the fuse checked as an open. new fuse it powered right up.
Hi boss,
i have question if you dont mind, if you have dc regulated power supply 13.8 volts same that one with 50 amps and 23kg of weight and u have psu power supply with 50 amps maybe 1kg kilo of weight, the question is they will output same 50 amps
The linear power supply is heavy because of the big inefficient iron and copper transformer.
A modern switch mode transformer can deliver a tremendous amount of current from a very small transformer due to the high efficiency of these high frequency power supplies.
if i use for powering car audio amplifier taht u need a lot of amphers. and the psu is100 amps for example which is better to use for car audio amplifier. thanks in advance.
Thanks for this. Gotta troubleshoot my 20 year old ps-21k. But what's odd, is that mine has the equivalent mbp351 rectifier, and according to my ps-21k schematics, all four taps are connected.
Thanks for the video Sir! Please advise where I can order the rectifier from - mine just quit other day!
I got it here:
leeselectronic.com/en/
My old 80 amp linear supply worked great..a bit heavy but back in 60's not many had fuses on both output binders...the smoke got out of that trans...what an odor..burnt varnished crapper door on a sailboat. Best trans I could get was a 42 amp..off the ten plate selenium rectifier. Swapped out old electrolytics and sold it for gas during rationing in 1973-74.
Good work 12v
73,
Superb as always. Curious - you expected bigger capacitors, are the smaller ones wired in parallel to make up capacitance? Less stress on the caps doing it that method perhaps. Really enjoyed your tutorial with the rectifier, thank you as as always!
Great vid! How come no load test?
It was, on my ham rig, not on camera.
is there any way you could get your hand on this one again my scr blew and i gave someone the scr to try to get me a new one and they have lost my part and its been a while so i dont know what it looked like or what the part number was . thanks for your time
LOL @ him pinging you! What amazes me is he's a HAM radio operator - and he cannot fix his own PSU?!?!? Reminds me of a boss I had many years ago, he had a degree in electronics (and I don't), yet he couldn't fix his satellite LNB, or his amplifier. He brought them both into work for me to fix. Go figure!
+GadgetUK164 That's the new era of CB'ers er, HAM operators.I myself am a licensed ham, a 2 letter call, and have had my license since the mid 80's. When I wrote my exam there was basically 3 classes of license, plus endorsements. First was the basic license which gave voice operation above 30MHz, and allowed for morse code operation in the "learner" portions of the band. This test covered mostly regulations, and some technical aspects. The operator was only permitted to use commercial gear, no home brew equipment. Once a ham was proficient in code, he/she could take the code test. 5WPM and 12WPM were the 2 standards, and depending on which test you passed it determined which HF bands that you could operate voice or "phone" as it used to be called. Power was limited for basic license to 200 watts if I remember correctly. The next was the advanced license, which covered the more technical aspects of radio design, and amplifiers ect., and permitted the hams to construct their own radio apparatus including receivers, transmitter and amplifiers. It also could be with or without code. Next there was the digital license, which covered basically all the digital modes. Again the HF portion needed code to operate phone on those bands, but it was OK to operate in digital modes such as RTTY, and CW.Now today, a basic license grants all privileges on all bands. The only restriction is basic license are not permitted to build their own gear, and that includes repairing it. To build or repair transmitting apparatus still requires the more technical advanced license. I look down my nose at the many of the hams out there as I see them as nothing more than CB'ers with a ham call sign now. All one has to do is turn on and listen to a repeater any evening, and you will know what I am talking about. There are a lot of "LIDs" out there and the last thing any respectable ham operator wants to be called is a "Lid" unless that happens to be the letters in your call sign.
+GadgetUK164 If a person has a good memory, they simply memorize the question pools and go for that extra. They're clueless in an electronics discussion. I have a similar PS, I consider this an easy repair. But I'll admit that I was thrown off about that negative connection until he explained it, I usually see TWO DIODES instead of a full wave bridge. 73, Don
+GadgetUK164 If a person has a good memory, they simply memorize the question pools and go for that extra. They're clueless in an electronics discussion. I have a similar PS, I consider this an easy repair. But I'll admit that I was thrown off about that negative connection until he explained it, I usually see TWO DIODES instead of a full wave bridge. 73, Don
I have to admit, I've never seen a earth center tap transformer used like that, but I still would have measured the short on the bridge and just swapped it out! It's nice to learn something new though! =) You are right that with education, you either learn it, or memorize it!
+umajunkcollector Yup, the good ones like the Astron do this. The cheap Chinese ones do it this way. I have another PSU on my bench for another ham, this one is the brand PYLE and it is the identical unit to this, bit no shorted rectifier, this one has a regulation problem, SCR crowbar was shorted, and there will be more parts. Will dig into this shortly.
Nice looking PSU, I use Astron for my radio gear (albeit I'm non-active, have them boxed up) have a 50 & 20 amp, great PSU's, just don't drop them on your toe!
+JacksJunkDotCom I am working on an identical unit, but badged PYLE for another ham that is blowed up real good. 4 big regulator transistors and an SCR to start with. Will pick up the parts on the weekend. Now that that big plasma that had me ripping out my hair is dealt with. Expect a video on that beast soon, as it was a real challenge, and I say that with emphasis on "challenge" as the easy way would have been to replace the logic board, but I wanted to find out what was the cause. I eventually got it going with the blow torch. I mean head gun.
Looking at the schematic diagrams. The Astron and Pyramid PSU's use almost exactly the same circuit design. Its funny because I hear arguments all the time about one being superior to the other...l
Is this AVE?
What is the type and brand of heat sink compound you use. Thank you.
Wakefield part number 120-2
Could you rewire the half-bridge to be full? would there be negative consequences?
It is a full wave bridge. Transformer center tap is ground. One half secondary conducts on positive swing (as other side goes negative) and when the AC reverses the other winding conducts. With a non center tap transformer 4 diodes used for full 2ave bridge. With a center tap tranformer only 2 are used.
@@12voltvids So if one were to not use the center tap and place the secondary across the full bridge, the rectified voltage would essentially be doubled....right? Which the regulation board most likely would not handle.....?
@@Ezzell_ that's right. Unless you used just 1 side and center tap. This way is more efficient though and that's why they do it. Full wave bridge you have 2 diodes in line for each half cycle and. Using a center tapped teavsfienwr just 1 diode so only .7v drop as opposed to 1.4v drop.
This is an old video but I just found it... I hope you're able to respond to my question... I have this exact same power supply and when I turn the voltage up, it starts clicking... Just rapid clicking and I see the voltmeter bouncing up and down a little bit. Any ideas?
It doesn't matter if there's a load on it or not I have been unable to take this apart as I no longer have a workbench after my second coma.
I would appreciate any tips as I use this power supply for a dual band rig requiring about 8 to 10 amps at 13 volts.
Thank you you have a great channel
Unfortunately it sounds like a regulation problem and that will require troubleshooting.
Greetings: I can relate. The damn beeping was annoying me here. The idiot mentality of the inconsiderate constant sending Msgs is 1 reason I gave up phones many years ago. Now I communicate by Eml. I hate Ppl that constantly bother with update inquiry. I update as it becomes available. If they show up whilst I am working on their unit. I stop and put tools away, or work on something else, informing them " since U think it is more important 4 me 2 talk 2 U I am done working on it 4 now". Most get the hint ' I DO NOT TOLERATE NEbody AROUND ME WHILST I AM WORKING', leave and await my updates. My customers respect that. I diagnose and repair 4 other shops. Most of the time these interuptions occur there.
Hi, Very good video! I have a question about a Tatung power supply I bought on ebay. It is a PS 3336 and it is suppose to put out 60 volts and 2 amps. When I turn it on and turn the volts and amps up it will go the 60 volts but the amps only goes to .16. When I put a load on it the volts drop back to 2 volts and amps stay at .16. I have inspected the boards and I don't find and burned out components. There is a big cap that charges to 72 volts and it is rated at 100 volts so it is fine. The power supply has 1 transistor in the back and it does not heat at all. It has a large transformer and it looks fine. Any ideas what cound be wrong?Regards,Arnold.
do you recall the value of the voltage regulator know (pot)?
Did you charge him extra for "pinging" you while you were working on his power supply..LOL
I am surprised that shorted diode did not take out the voltage regulator, I would have assumed being shorted it would pour AC into it.
+old64goat Nope AC never got that far. Appears as a dead short across one side of the secondary winding.
Why did you think it was the bridge? Typically they fail short. What happens then?
I’ve been teaching nearly 40 years. My experience is so different that I could benefit from your thoughts.
Why didn’t the electrolytic bulk cap NOT explode? Nuts.
The transformer was drawing too much, so I knew a serious overload. The first thing to do, disconnect the rectifier and check.
Ive had similar repairs with a 30Amp manson and kenwood supplys, yup the bridge went to silicone heaven, i found a 35A fuse in the holder, why do people do it :-(.
Im getting some of your favorite capacitors today, i have a crappy zalman zm750-hp atx supply to bring back to life, its full of evil CapXon capacitors :-(.
Fresh from r.s semiconductors im getting panasonic FR and FC series low esr types, i matched the esr and ripple to slighty better that the originals, 1000uf and 470uf 16v, not as good as rubycon or nichicon but they will do very nicely :-D
Rectifier checked out good, what would be my next step? 4 transistors on the back? IC? Alarm sounds when plugged in.
ua-cam.com/video/WPHwh5Z8tc0/v-deo.html
Please watch this one for the Pyle power supply. It is identical to this one, and was in the "buzzer" mode. Failed regulators were the problem, and it triggered the protection crowbar which put a dead short on the output.
Just watched it right after I commented, will swap those four out tomorrow and see how it goes!
I accidentally fed 24VAC to the output of the Pyramid PS26KX and blew something. Now I only get the "PROTECTION"" alarm and no output. I replaced the LM723 IC, but this did not do anything. Do you have any suggestions to get this working again? Any help is appreciated. Thank you!
Probably blew the regulator transistors.
@@12voltvids Thank you! Based on the schematic and visual of the PCB, I need to replace one LM7812 and one TIP41C. Would you agree? Link to the schematic below: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/www.repeater-builder.com/pyramid/pdfs/PS26KX.pdf
@@12voltvids Thank you! I checked the schematic and PCB, and I see two. LM7812 and a TIP41C. Replacing these two should do if if you had to guess? Thanks again!
Is it normal for my PS-26KX to make a fading beeping sound after I shut it down? Some kind of capacitor discharge?
I have Dell mini ATX power supply. It fried and I had to test it, so I shorted POWER ON pins and it still did not start up. So I just opened the case and tested diodes, diodes were fine. Just forgot to disconnect power cord and tried to put cover back and I got shocked from the case touching the radiator (common ground). So I found out that all the ground was under 225VAC. After testing continuity I found out that the rectifier bridge IC was shorted. Both + and - were hot 225VAC. After removing rectifier bridge, there is still 40VAC on the + and - side where the bridge connected in circuit, so I guess the 40VAC is coming from the shorted transformer secondary coil.
Doubt that. You are referencing the chassis which is cold ground. You need to connect your meter to the hot ground when working on componets on the primary side.
12voltvids As I said, the ground was hot, somehow L was leaking to the common ground and I got shocked. That was a good lesson to test with screwdriver-lamp first, my body is the "cold ground" in that case and yes, the radiators were full AC Line hot before I desoldered rectifier bridge.
I have a power supply question. I'm sure you know that some microphones require 48V DC phantom power. If an audio interface runs on 12VDC, as many do, how is it possible to produce 48VDC for the microphone when DC won't work through a step-up transformer? Even more confusing, how does a PCM recorder that uses household batteries supply 48VDC phantom power?
+CraigTube They use either a DC-Dc converter or buck converter.A DC-DC converter is essentially an inverter. The 12VDC or battery power is converted to high frequency square wave chopped DC, where it goes through a transformer to step up. Rectified and filtered.A buck converter is basically an oscillator with an inductor, and a diode/capacitor to rectify the higher voltage pulses from the collapsing magnetic field in the indictor. This gets added to the original DC. Buck converters are used for low power applications like phantom power. DV-DC converters for higher current devices such as powering VFD displays, or powering higher voltage circuits.
Could I use a 02 part instead of the 01 part.
Hi i have a question i buy a new power supply PS36KX and i only turn on to see if it's work fine but when i move the volts switch do not goes up (do not increase volts ) , and i don't have anything connected to it , that is normal ??? is the first time i use one of this
what a nice fix
but..
i was wodering about:
the jop of these big metal transistors which are in the back of the power supply
.
what do they do?
+Osamah Najjar Those are the voltage regulation transistors.This power supply is a variable voltage so the voltage can be adjusted.The transformer puts out about 20 volts after the rectifier, and the voltage is smoothed out, and regulated by those transistors, and the rest of the current that is not needed is dissipated as heat. So you need several large transistors to cut the raw unregulated voltage down to the desired voltage.
+12voltvids.. thanks
Hello 12voltvids, I have the same power supply with what I think are regulator circuit issues. As soon as powered up the red over current protection LED and beeper are activated. Any chance you will be posting your new video soon?
+Mike C
Yes it is up. It is a Pyle power supply and is identical to this. It ha the buzzer and overload alarm going off as you describe. The video shows what happens to that one. 4 transistors on the back of the unit and the scr crowbar.
Does this mean you could have just used the original rectifier, and just altered the connections, so as to utilise 2 of the good diodes?
no it was shorted
@@12voltvids I though you said it was just one of the diodes of the 4 that was shorted
@@reacey 1 was but a full wave rectifier uses 4.
Whats that pcmcia card? Network or modem?
+Jim Reardon Its an analog cellular modem
Fantastic, can you use this power supply to as a bench power supply to work on electronics as you do for repairs? If not what would be the best type of power supply to use as a tech..thank you Merry Christmas.and happy new year.
If you are working on car audio and such then yes absolutely. It is regulated and adjustable from 6 to 15 volts, however is not current limited.Proper bench supplies are a better choice as first they can generally be set between 0 and 30 or 60 volts depending on the model, and they feature full current limiting. So if you know that the circuit should draw 2 amps, you can set the power supply to 2 amps max. That way if you have a dead short you won't do further damage. This one puts out 21 amps, so if there is a fault there will be a much bigger fault if you connect it with no fusing.But then again a proper bench supply costs much more than one of these.When I ran a shop I had a proper bench supply, 0 - 30 volts 0-5 amps.I didn't work on car audio though. For big amplifier repair this would be fine.
12voltvids Thank you, is there a model or two you can recommend to send me on the path to purchasing one ? Thanks again and happy holidays.
I don't like the two diode full bridge rectifier configuration, smoothing the ripple never seems to be as good.
I have question: I own PS26KX and wanted to use it just to provide linear power supply to just one audio amp but the fan was too loud. What could happen if disconnect the fan - may amp will draw no more than 1.5A, it is 12V, 18W device.?
i would put a resister in line w the fan to slow it down..dont unhook it tho ...someone wont know it
Appreciated your video. Hm....YOU MAY HAVE TESTED WITH A LOAD BUT IT IS NOT SHOWN IN THE VIDEO. Can't verify pass transistors and regulator board/filter caps w/o load. I'd load it (somehow) and feel the pass transistor casings for equal thermals? Bet filter caps are lunched.
Tnx man. Common issue with these junks
Sure is
@@12voltvids I have a feeling that the el caps are shot too. Which would make parts worth more than the power supply. Ugh
@@JayN4GO they are probably fine. El caps fail far less than the internet experts say. The odd one fails now and again and switch mode power supplies eat them up pretty good and some bad batches that cropped up in some devices but i have devices that are 40+ years old and still work perfectly. I have an astron rs30 power supply which has not been turned off since new in 1993.
@@12voltvids ok. Yeah 4 of them seem to have leaked a maroon color onto the board. I thought it was glue :(
@@JayN4GO that white glue that holds stuff down can turn conductive
Great video
(Say, who was that masked stranger???) I really mean what was that strange hand tool on your work bench?
+John Schroeder Those are called nickel press pliers and are used to set 3M Scotchlock IDC connectors. Many people just use pliers, but the problem is pliers don't apply even pressure, and don't set the IDC crimp on properly. They are mostly used in telecom industry, and for splicing network wire ect. You just place them over the insulated wire and crimp them on. They are filled with a moisture displacing gel so they can be used in damp locations. The other gadget is a vintage PCMCIA cellular modem, with the cable for an old Motorola flip phone. Way back in the analog cell and dial up days that allowed an old analog cell phone to connect your computer to a dial up modem. That thing is old as the hills, and probably cost a bloody fortune. The card has a standard telephone jack too to plug in a regular phone line. It is only a 14,400 dial up.
+12voltvids As always: informative. Tnx.
Ham radio addiction withdrawal symptoms! Doesn't he have a car battery and a battery charger kicking around? :D
Or does he need a new excuse to get away from the XYL :D
How to repair 12.v inverter smps
Thanks for the video. But after seeing the waste inside of this power supply, Idk how or if Pyramid is still in business. Using a center tapped, probably 800KVA, transformer that probably cost $100 and only using half the windings (thus half of the current capabilities) for the unit. Versus separating the center tap and making 2 individual 12V windings and wiring them in parallel and using the entire bridge rectifier and adding maybe a few more caps at $0.75 each or just increasing the size of the existing capacitor bank. Extremely wastful design on Pyramids part. IMO
That is a high power PSU for a radio, is he talking to people on the moon?
My power supply is bigger than that. Most 100 watt radios will draw close to 20 Amps. Most hams will power up multiple radios with a single power supply so therefore you need a big power supply.
@@12voltvids Last time I used a radio was when I was a child aprox 40 years ago, we called them CB radios in the UK and were widely used. We would hook it to a 3 amp battery charger, could reach hundreds of people in our city.
Suppose it a bit different in the US as there's more space & open between homes.
@@PF-gi9vv we had/still have cb radio. Hams refer to it as the chicken band. They operate on the 11 meter band at 27mhz. Ham radio in the HD spectrum has 160 meters 80, 40, 20, 15, 12, 10m which is 28-29 mhz. Of course in different countries they used different frequencies for cb. Here hams always considered it a piece of their band as it was originally part of the ham band and the FCC in the us and doc in canada sliced off a sliver of the band and made a new channelized service for citizens use. Low power with distance restrictions. But that didn't stop us from talking skip when the band opened up every 11 years.
Linar take also better trans. from tom the powerline. Switching stuff
good stuff, thanks...
Love your videos. What's your call sign.
My memory is off. I thought current flowed through the diode in the other direction. Opposite of the diamond shape. I can remember having to remember however a full wave rectifier was wired. But I forgot, lol.
A lot op people are saying the current is flowing positive to negative now. we were taught that current flowed negative to positive why would a proton go to an electron. In a dc circuit
@@fredguitarman3536 oh yeah. Before I took electronics in High School, I believed it went from positive to negative. They told me the opposite was true. So my assumptions were correct before I was "educated". That just makes it more confusing to me, lol. NPN Transistor I named (not put in) meaning the arrow points away from the center. PNP was "put in in". Arrow pointed inward.
Any clue how to get a switcher to shut up? lol. I have a 55 amp that just screams with rfi.
+Cruiseomatic
Switching psu are noisy. You can try to shield them and use chokes and caps but they are noisy, and kick out lots of harmonics , rfi etc. That's why I stick to linear for my radio gear.
+12voltvids This one runs two peltier type iceboxes, 3 radios, a dtv converter box, lights and misc. gear. A linear the size I need would run hundreds and this one I have was free, lol. It has 55 amps at 14.5. How would I start to "choke" this one? I tried torriods on the in and output. Did nothing.
+Cruiseomatic Yes linear are pricey due to the amount of copper and iron in the transformer. Sorry I can't be more specific on noise reduction on switchers, as I have never tried to eliminate RFI from switching supplies. I run linear for this reason, so I don't have to worry about it. I run 2 Astron 35amp connected in parallel.That gives me 70 amps peek, can run 55 all way long and they don't even get warm.I can run my entire shack on theses.Most of the noise is coming from the transformer on a switcher, as they are typically running in the 60-100KHz range.They throw a ton of RF out.
Obviously, there has to be a reason the rectifier shorted.
User error more than likely. B
why replace the original diode? just swap over the wires to the other 2 diodes that were not in use )))
Well because they are shorted duh.
Isn't a HAM operator supposed to be able to fix a power supply by him self?
When I first was licensed, an amateur radio operator needed to be able to demonstrate working knowledge of a radio station. In other words you needed to be able to build a transmitter and receiver. You didn't actually have to build one, but you had to be able to explain how a radio receiver, and transmitter operated. Working knowledge, and if you had that working knowledge, then given the parts you would be able to assemble and test the equipment. You also needed to speak the language of (-- --- .-. ... . / -.-. --- -.. . ) For those wondering what I just said, well it is "morse code" which is something that I learned many years ago, and then promptly forgot due to disuse. Today a ham has to only answer some multiple choice questions about regulations, and operating procedures, and they are granted full privilege. I get asked to work on rigs, but I usually turn them down, just because I don't have the required test equipment. I stick to the AV gear.
Ah, ok, when I took the test I also had to do a test on morse and a test on electronics and how radio's worked
It's that way in Norway atm, to get a license, you need to learn electronics.
If the owner of this power supply watches this Video............You CANNOT rush the repair of high voltage components. You drop it off, shut your Mouth and wait.
+Amy Marie The owner is a very good friend of mine, and believe me I have already slapped him for sticking a 15 amp fuse in place of a 6. He used to do voice over work for me on corporate videos and is a ham, but unlike most hams, he is not a technical guy. He can handle the operation of his radio, and put up antennas ect, but when it comes to the internal workings, well I get the work, and end up doing it for basically free. I charge him for the parts.I have known him for 40+ years.
ah well then, I Take back some of what i said.....however.........I am curious, what caused the BR to go "pop goes the weasel"?
+Amy Marie Could have been any number of things. Doubt that it was an overload though because that would generally bugger up the regulator transistors. Doubt it was a surge either as that rectifier is rated 600V, and it is running on perhaps 35. Likely just a bad part that ran for awhile and just failed. If it had been an Astron it would have never failed. My astron was kit with 240V when the neutral let go on my shack, and I lost an compressor on my air conditioner, and freezer, and a bunch of other electronics. The astron, all it did was pop the fuse. But then again, Astron are built in the USA and they are bulletproof. You do pay for that quality. They are heavy duty units that can run at rated output 24/7 and not even get warm. I wouldn't try that with this light weight.I should do a show and tell comparing my Astron to this light weight, and you will see the quality difference. This one had tiny little filter caps, my Astron the caps measure about 2" in diameter each, with big screw down lugs on top. It is a thing of beauty.
Gah! you're making me drool......Lol. My Thoughts strayed to A "lightining Strike" I know you guys get some wicked storms on the west coast.....
+Amy Marie Lightning whats that? Been so long since we had a good storm here.We might get 1 or 2 little thunder shower storms a year if we are lucky. No drive a few miles east, into the mountains and that is a different story, or head to Calgary the land of the lightning and some wicked storms.
So you could have used the other two good diodes on the partially blown old bridge rectifier and saved yourself a little money and time - lol
No because they are the wrong polarity.
@@12voltvids AH! I didn't think of that.. but thought I was being clever ;-)
@@justincase9638 Plus the fact that 2 of the diodes are dead short so unless they were physically removed it won't work anyway.
A decent PSU
THANKS
WTF he can't fix his own PSU!
A Ham Appliance Operator. What ever happen to real Ham Operators, they are supposed to fix their own gear. De AA2PR.
these videos must all be crap since they all end after just a few minutes of play
Turn off your ad blockers. The only way I make money is from the advertising. No ads mean no money. No money mean no videos.
Make sure you charge him more than the units worth