The quest for finding an anything-but-red LED to place behind a very red filter was quite amusing, and to be honest the end result was not that surprising... :)
@@russellhltn1396 Yes I was a little bit of a dum dum there too, I didn't realize the filter extended to the LED array on the right. But once I realized that, as you can see in the video, I **did** try it before ordering the parts. However the wavelength of the LED bar ended slightly different from the one of the single LED in the wrong direction, and the filter cut-off is surprisingly abrupt. Oh well, at least others won't have to discover it the hard way...
@@CuriousMarc Simplest is one of the hyper bright red LED's, which will be around 20 times brighter on 20mA over the originals. Take the 5mm package and simply use a grinder to make the top flat, and leave it with the ground surface, possibly sanding with some 180 grit paper, to diffuse the light. Those LED's are really bright, and even the yellow should be visible, as they are daylight visible.
Unless you use it everyday don't buy one. The maintenance and its cost won't worth it. If you could live without one for 25 years once you buy it you will hate them for the next 25 years. To me it's like smoking a pipe. It has too much hassles ;)
@@bayareapianist I honestly don't mind cleaning it when it nicely takes out a 24 pin plug without damaging even one pad. That would take me hours with a sucker and wick. I'll take the 5 minutes of cleaning. What I can see is how in e.g. a company the thing will always be full of solder because the previous user didn't clean it, like the one I used 25 years ago. But if you have your own one at home and clean it after use, it'll always be there for you when you need it. You'd be surprised about the cost these days. You don't need a Hakko or a Weller for occasional use.
It's very good to see that professionals make the same stupid mistakes the rest of us do. This is why my Fluke has a nice feature where it complains if you don't have the probes plugged in the right outlet based on the selection. Been there, done that. And that probably is as close i'll ever be to compare to your expertise :D Thanks for the video.
Yes, the Fluke complains. But only on start or when you change the selector. I managed to blew the first fuse on mine because i didn't look on startup and used it with the already connected leads... Therefore, all hail to the old mechanical solution with the plastic disk blocking the plugs. I have one at work from Gossen Metrawat. The only problem: it actually isn't equipped to measure amps directly. Only works with an intermediate clamp. 🤦♂
This power supply was actually manufactured by GW Instek and was rebranded for Tektronix. As for the Dallas Battery Backed SRAM you can still purchase new ones from Digikey. It only holds the calibration offsets (calibration instructions are in the manual) and the user settings so no big loss if it dies you'd be surprised how long the batteries in those last. You can also ditch it and replace it with FRAM such as a FM16W08. It has the write speed of SRAM but is non volatile and doesn't require a battery. With a custom made SMD to DIP adapter PCB and some glue logic I used a single quad NAND gate (this FRAM latches the address when CE goes low so CE must be toggled for each address read or write). The original SRAM doesn't latch addresses so many devices simply hold CE low constantly sets the address and brings OE low for reads and WE low for writes.
This video is dedicated to all cap changers. @CuriousMarc is Chuck Norris. He can repair dual channel power supply by measuring current only on one channel.
I don’t think many understand how the magnitude of power efficiency has improved over the past 50 years. Even compared to just the 80’s, let alone the 60’s, we are SO much more efficient in our usage now.
Highlighting the one LED with a printed frame was an elegant solution. After the yellow LED failed I wondered what your solution was going to be. Nice thinking!
Hello Marc. Nice work! What a lab you have -- with every camera angle I see more, and multiple types and numbers of test equipment. One thing I noticed on your Tektronix triple power supply was the acronym GPIB. It took this brain of mine a minute or two to recall the General Purpose Interface Bus implementation of the IEEE standard of the 1980's. This was an 8-bit parallel bus standard that came out of HP for test equipment. As a software consultant I learned never to throw anything away. In the mid-80's I wrote a driver to support the protocol for a wirecutting machine in the mid-80's. About twenty years later, I used that code as the foundation of a module of C# middleware so that my client could interrogate and read vital signs from a family of medical devices with a "mysterious" GPIB port. This company had plenty of skilled programmers, but no one there had ever seen a device without a USB port or an Ethernet jack. One serious problem in our tech world is the view by management that senior staff is an excess expense that ruins the bottom line (we're paid too much) and productivity (we don't crank out 300 lines of code a day, like a 28 year old wonderkind.) So, most mid-sized companies either move their older technical staff into management, or get rid of them through early retirement, or worse. Then when a real problem comes along that can't be solved with the Java or Microsoft class architecture, they're lost. That's how I once made my living -- putting out fires caused by bad business and/or technical decisions -- but it can wear you down. They're always in a hurry,because they could of called you months earlier, and the young hot shots are usually rude and resentful because you've been hired to fix something they could not. Glad that I'm retired, but I miss the income.
20:03 Marc using a hot air gun nozzle it may be faster to retract these self-welding sleeves. With these Fluke multimeters, what has happened to me too often after using it as an ammeter, is to use it to measure a voltage without having moved the wires. The fuse must then be replaced.Thanks for all your sharing. You are doing a great job.
I actually have an infrared heat tool from Raychem designed for installing those solder-shrink connectors. I picked it up at surplus for around $25 about ten years ago. Back then there were about $2000 new. Now they are only made on request and cost over $10,000!
Instead. Non insulated crimp terminals, and lined heat shrink. It is the most logical and superior repair. Crimp can be verified before it is sealed. Lined heat shrink can be any color you like, or clear.
I’m a happy user of gas-free 4-point crimped splices, aerospace-style. They are bare metal, just cover with a shrink tube of your fancy :) I’m not a fan of the solder-in-tube splices because they require very well prepared wire ends. That’s often hard to achieve in repairs. The solder-in-tube works great with fresh shiny copper. Anything less than that and it’ll pretend to work for some time than bail. I’m glad the folks at the Connections Museum had the wiring plant that was good enough to use those. When they work, they can save cost. But I’m still preferring the 4-point radial crimps. No need to worry about the wires stating in the middle of a splice or anything like that. And sometimes you can find them surplus in big quantities. Disclaimer: “sometimes” has been once a decade for me.
You need a capacitor leakage tester that can measure the leakage current at full working voltage so you can weed out faulty capacitors like in this PSU. I recommend the HP 4350A, an old model but still very useful today.
Oh, Dallas Semiconductor and that blasted internal battery!! Where I worked until 2010, we had an old 486DX33 that became support equipment. This computer had the problem of forgetting the hard drive settings, and that chip stored the information. The computer was setup for programming Allen-Bradley PLC2 programmable controllers. The software would not run in any emulation in Windows, and had to run pure MS-DOS 6.22. I had to hack into one of these to bypass the internal battery. I ended up cutting conductors and soldering wires connecting to a dual D cell battery holder. I used D cells because maintenance kept them in stock and there was room inside the steel PC case. The PC went to Mexico with all the rest of the equipment when that place closed.
Sheesh Master Ken would have spotted the mistake before you powered on and Eric would have fixed it with his finger thats what you get when you try to have all the fun alone 🙂
So true. Master Ken would reverse engineer the zero reading to its source in a flash. But hey, it’s a comforting thought that even the master of faultfinding gets his wires crossed sometimes 😉
Thanks for the video, Marc. Now I know the correct replacement fan I need to buy for my own device. It's really a great PS, but I avoided to use it because of the noisy fan.
I just tried those splices for the first time to make some Christmas lights longer. They're outdoor rated and made the 60 splices pretty easy actually. Luckily that spt-1 wire has some pretty thick insulation so it didn't come close to melting. I was surprised
I have one of these and it's pretty awesome. I bought it since it was the only triple power supply I could find that has three fully isolated outputs. This lets you change which outputs are positive and negative, and there's relays in it that will let you series or parallel the 20V supplies to get more voltage or current. The other good thing is it's 100% stock parts. There's no custom chips or other parts except the main power transformer which is kind of weird for a tek product.
it's always a crapacitor, this is exactly why I always replace ALL the caps in old gear even if they test OK... as like you experienced sometimes they breakdown when exposed to voltage.
The worst design fault of this supply is that the "Auto Sequence" button has "ON/OFF" silkscreened onto it, which makes it look identical to the Output ON/OFF button unless you're paying close attention to the far less obvious text printed above the button. On more than one occasion I've gone to turn off the output and hit the Auto Sequence button by mistake, which causes it to start stepping through all of the memories. I've never bothered to set these up and on mine they defaulted to the maximum voltage and current limits, so my circuit that I intend to be supplying with 3.3V suddenly gets hit with 20V and a 2.5A current limit. I definitely reccommend storing a low voltage/current into all of the memory slots so that accidentally pushing this button is not so destructive. I'm afraid every time I turn mine on that the Dallas battery is going to be dead and the calibration wiped. So far it's still holding out... but one of these days I really need to pull it out and dump the contents at least before it dies. I think I've seen people make boards that replace the Dallas module with a microcontroller and FRAM (which, like core memory, needs no power to retain data), but last time I looked into it I couldn't remember which Dallas part specifically was in the supply to see if any of the existing designs were compatible. Thanks for your video which clearly shows the part number. (As you know, it's kind of a pain to disassemble). When I take it apart again I'll do the fan mod as well-it is indeed quite loud.
when i worked as auto-electrician we used mini torches to melt the shrink connectors for watertight connections. Those torches also work as soldering guns, so would assume they would do the job to melt your solder connectors. They just require a little practice to not melt the other wires in a bundle. They're also quite cheap and still mass produced because they're also used in cooking
Great video! Thanks for posting. I have the same power supply and ran into the same issue a few weeks ago. You saved me so much trouble shooting time 😀. I ordered the new caps and fuses you recommended and I'm back in business. Thanks!!! I even had the same complaint about the loud fan so I swapped that too. Keep up the good work.
The red color filter in front of all those LED's is a bandpass-filter. It passes low frequencies (high wave-lengths) in the red spectrum and blocks everything else. Green (and yellow) are at higher frequencies and can therefore not pass that red filter. ;)
I did like the solder splice, we used them in aircraft when I worked for manufacturers. There's a variant with a black pigtail wire that's very useful for grounding shielded wires.
Those splices are great. They're used a lot in automotive wiring repairs. Perhaps you could change the current limiting resistor for that LED, and "turbo charge" your replacement LED bar? I agree with you on wanting a clear "This is hot" indicator!
From wikipedia: The capacitor plague was a problem related to a higher-than-expected failure rate of non-solid aluminium electrolytic capacitors, between 1999 and 2007, especially those from some Taiwanese manufacturers,[1][2] due to faulty electrolyte composition that caused corrosion accompanied by gas generation, often rupturing the case of the capacitor from the build-up of pressure.
I too had bought the all-in-one sleeve and soldering. They are great for doing DIY and medium temperatures. But unfortunately when you do it in an engine bay the heat exceeds and the wires come on soldered. Very frustrating
The DS1220Y-200 is the same as in the HP3458A, CALRAM. It's still available, but check for cheapest version, like faster access and/or other supply voltage compliance. Some day soon, I'll have to replace that in my 3458A again. So better do it soon, and don't forget to copy the content first, should not be as crucial as in the DMM.
As an electronics engineer / electrician of over 35 years, I've never connected a piece of test equipment up incorrectly, put a component in the wrong way, not connected wires back up after fault finding, grabbed hold of high voltage capacitors that are charged up, let the magic smoke out. Can any other engineers think of anything that I ''haven't'' done? 🤔
Nice repair! The Fluke is a good dmm, but I see it offered you some traps: it has no input jack alert, defaults to AC amps, to exit stand-by mode just press a random button...funny to watch, thanks!
Surprised the Connections Museum uses solder splices. Scotchloks are a telephone company favorite. My favorites for quick splices are AVX Poke-Home wire-to-wire connectors. They don't require a soldering iron, heat gun, or crimping tool. You just push the wires in.
It might be a bit much trouble, but consider adding a circuit to flash the output indicator to help it stand out, then you can stay with red and get good illumination.
There's another youtuber on here who has made a replacement for the DALLAS module of death. That runs from normal replaceable coin cells and its a direct plug in replacement. He goes by the name necroware, might be worth reaching out.
Although the NVRAM ICs can still be bought, for many it is easy to carefully mill away the plastic over the connection to the internal battery, disconnect the IC from the dead battery and connect it to a pair of wires and a conveniently placed CR2032 cell. Since the datasheet shows no NC pins, I suspect they are below one of the narrow ends. I wonder if using a 28C16 might work as well, given that the DS1220 has no RTC.
No need to mill away the cover, it will pop off. Beware of poor soldering on the RAM pins near the edge of the PCB. We used those at 3Com and they were a constant quality headache. I would replace them with a mini PCB with RAM on the bottom and a CR2016 holder on the top.
My HP8753D VNA stopped working a couple weeks ago. I've been putting off tearing into it but I suspect that the issue is in its power supply too. Hopefully just plague caps that fingers crossed haven't done lots of damage.
Very mundane question: what label maker did you use to make your little LED frame for the front panel?? I've been trying to find one that prints white text on a black background, and you seem to have found one!
Another nice thing about the P-touch is that you can get heat shrink on a spool, so labeling wires or bundles is easy (I _hate_ flags!) One thing to note is they are sold by the flattened width of the tube (1/2 the circumference) _not_ the diameter it will fit over.
Marc, what is the make/model of the workbench you are using in this video? I really like the depth of the shelf and working table underneath plus the monitor mount location.
Excellent choice of fan, seems to make a surprising difference. I took a different approach and built a fan speed regulator for my vaguely similar GW/instek GPC-3020 . I'd post a link but YT usually flags it as spam - it's easy to find on my channel, or directly with video ID # 3FC4myguLyw .
I think I would have taken your approach too. Doubtless it is only noisy because it runs flat out all of the time. I would worry that a replacement might not provide as much airflow as the original, but I am sure that Marc has taken this into account.
I encountered a shorted electrolytic cap recently. Zero ohms. Usually, they just blow up. This one was shorted but the 5 volt regulator current limit saved explosion.
@@buckykatnga I must of been lucky,,as you rightly say they go bang sometimes,which makes it difficult to know the cause,many PSU / Monitor repairs back in the 80,s had input caps blowing, because customer was forgetting to check if 110/240 switch was correctly set,auto switching was at an early stage.Many a new workshop engineer jumping,with clouds of smoke belowing from equipment LOL
I would like to see a video on controlling the HP3438A DVM over HPIB.. I am designing a esp32 to HPIB interface that I hope to use with it... I would also like to do the same with power supplies and other lab equipment.. Especially that NASA NIXIE frequency counter... Turn it into an universal display for everything numerical...
Yes, you have to choose one with enough flow and static pressure. That’s why I couldn’t go with the really low noise ones. But at least this one I can live with.
If your Dallas chip has become useless anyway, no risk to try Dremeling the top off and prying the old batteries out and soldering on a new button cell holder. If you have access to a milling machine, that might be a safer way, take a few tenths of a mil off with each pass.
Not sure if the new fan is a good idea... I'm pretty sure they chose the loud one for a good reason. I have done similar mods, and most of the time the device got significantly hotter with a silent fan.
You have to buy one with the correct flow and static pressure. Which is why I could not go with a truly low noise one. This one is just less obnoxious…
Just replace the fuses with thick pieces of wire. You know, like back in the day when homes had those screw-in fuses and people would put a penny in the fuse socket and screw in the fuse on top of it to hold it in place. That'll get the power flowing again. I'm sure it's perfectly safe... 😉😂
Marc - if you find a good solution for the DS1220Y part please let us all know...I did see another comment lower that talks about the DS1220 and will investigate that as well. Have two old HAL ST-8000 TU's that I replaced long ago and I'm sure are DOA by now. 73 - Dino KLØS
I’m surprised too! The blue Tek meter certainty does complain about it. If you look at the footage closely, the Fluke flashes “Lead” for maybe a second, but then it goes away. Maybe the lead detection microswitch is not working correctly anymore?
Have you guys ever blown a power supply by putting two in series? It has happened to me at least twice. However when I connected them in parallel and then I use one's current limit, nothing happened. Do you guys have any explanation for this?
@@ChrisSmith-tc4dfdefinitely not. The negative of each ps was isolated from the main ground wire. Usually there is a piece of metal connector negative to ground. I have removed them all. Besides, if the negatives were connected to ground, one of the ps would have been short circuited.
Probably a power supply whose design was not thoroughly tested in series operation. Even a few HP supplies get damaged when you back-drive the inputs, and series operation is exactly that. So, explanation: supply not good enough.
I guess that display filter blocks all colors except for red. I would have thought the bright green LED would work at least a little bit. Not seeing the green and yellow was unexpected.
That's how filters generally work. That's why a red filter is red. I have a ridiculous surge protector with neon bulbs to indicate status, and one has a red filter, the other has a green filter. Good luck ever seeing the neon under the green filter.
@@CuriousMarc The form factor of the PS2521G is certainly much more bench friendly. If I found the right specifications, it however outputs "only" 5A @6V + two times 2.5A @20V for a total of 130W (output). The 6623A is meant for unsupervised industrial applications in a standard 19" rack and outputs up to two times 40W (2A @20V or 0.8A @50V) plus one time 80W (up to 10A @7V or 4A @20V) for a total of 160W. It has an awfully loud fan though😆
so nice that all your equipement is falling apart !
Yeah when I buy one on eBay and it actually works it's kind of a downer. I won't get to know how it works ;-)
The quest for finding an anything-but-red LED to place behind a very red filter was quite amusing, and to be honest the end result was not that surprising... :)
It's possible, but I'd think you'd need to start with a much brighter LED. I think the lesson here is to try it before ordering parts. ;)
@@russellhltn1396 Yes I was a little bit of a dum dum there too, I didn't realize the filter extended to the LED array on the right. But once I realized that, as you can see in the video, I **did** try it before ordering the parts. However the wavelength of the LED bar ended slightly different from the one of the single LED in the wrong direction, and the filter cut-off is surprisingly abrupt. Oh well, at least others won't have to discover it the hard way...
@@CuriousMarc Simplest is one of the hyper bright red LED's, which will be around 20 times brighter on 20mA over the originals. Take the 5mm package and simply use a grinder to make the top flat, and leave it with the ground surface, possibly sanding with some 180 grit paper, to diffuse the light. Those LED's are really bright, and even the yellow should be visible, as they are daylight visible.
great buddy 👍
you inspired me to buy a desoldering gun, 25 years after I tried one that wasn't cleaned in ages and hated it. It saved my bacon twice today.
Nice to hear. I should have bought mine way earlier too!
Unless you use it everyday don't buy one. The maintenance and its cost won't worth it. If you could live without one for 25 years once you buy it you will hate them for the next 25 years. To me it's like smoking a pipe. It has too much hassles ;)
@@bayareapianist I honestly don't mind cleaning it when it nicely takes out a 24 pin plug without damaging even one pad. That would take me hours with a sucker and wick. I'll take the 5 minutes of cleaning.
What I can see is how in e.g. a company the thing will always be full of solder because the previous user didn't clean it, like the one I used 25 years ago. But if you have your own one at home and clean it after use, it'll always be there for you when you need it.
You'd be surprised about the cost these days. You don't need a Hakko or a Weller for occasional use.
It's very good to see that professionals make the same stupid mistakes the rest of us do. This is why my Fluke has a nice feature where it complains if you don't have the probes plugged in the right outlet based on the selection. Been there, done that. And that probably is as close i'll ever be to compare to your expertise :D Thanks for the video.
Yes, the Fluke complains. But only on start or when you change the selector. I managed to blew the first fuse on mine because i didn't look on startup and used it with the already connected leads...
Therefore, all hail to the old mechanical solution with the plastic disk blocking the plugs. I have one at work from Gossen Metrawat.
The only problem: it actually isn't equipped to measure amps directly. Only works with an intermediate clamp. 🤦♂
This power supply was actually manufactured by GW Instek and was rebranded for Tektronix.
As for the Dallas Battery Backed SRAM you can still purchase new ones from Digikey. It only holds the calibration offsets (calibration instructions are in the manual) and the user settings so no big loss if it dies you'd be surprised how long the batteries in those last.
You can also ditch it and replace it with FRAM such as a FM16W08. It has the write speed of SRAM but is non volatile and doesn't require a battery.
With a custom made SMD to DIP adapter PCB and some glue logic I used a single quad NAND gate (this FRAM latches the address when CE goes low so CE must be toggled for each address read or write). The original SRAM doesn't latch addresses so many devices simply hold CE low constantly sets the address and brings OE low for reads and WE low for writes.
This video is dedicated to all cap changers.
@CuriousMarc is Chuck Norris. He can repair dual channel power supply by measuring current only on one channel.
I don’t think many understand how the magnitude of power efficiency has improved over the past 50 years. Even compared to just the 80’s, let alone the 60’s, we are SO much more efficient in our usage now.
Well you also gotta think this is a very much fully linear power supply. Nowadays we mostly use switching supplies. Quite good but very noisy
Highlighting the one LED with a printed frame was an elegant solution. After the yellow LED failed I wondered what your solution was going to be. Nice thinking!
24 minute episode, late saturday evening, why, Marc, you really are spoiling us.
Hello Marc. Nice work! What a lab you have -- with every camera angle I see more, and multiple types and numbers of test equipment.
One thing I noticed on your Tektronix triple power supply was the acronym GPIB. It took this brain of mine a minute or two to recall the General Purpose Interface Bus implementation of the IEEE standard of the 1980's. This was an 8-bit parallel bus standard that came out of HP for test equipment.
As a software consultant I learned never to throw anything away. In the mid-80's I wrote a driver to support the protocol for a wirecutting machine in the mid-80's. About twenty years later, I used that code as the foundation of a module of C# middleware so that my client could interrogate and read vital signs from a family of medical devices with a "mysterious" GPIB port. This company had plenty of skilled programmers, but no one there had ever seen a device without a USB port or an Ethernet jack.
One serious problem in our tech world is the view by management that senior staff is an excess expense that ruins the bottom line (we're paid too much) and productivity (we don't crank out 300 lines of code a day, like a 28 year old wonderkind.) So, most mid-sized companies either move their older technical staff into management, or get rid of them through early retirement, or worse. Then when a real problem comes along that can't be solved with the Java or Microsoft class architecture, they're lost. That's how I once made my living -- putting out fires caused by bad business and/or technical decisions -- but it can wear you down. They're always in a hurry,because they could of called you months earlier, and the young hot shots are usually rude and resentful because you've been hired to fix something they could not.
Glad that I'm retired, but I miss the income.
20:03 Marc using a hot air gun nozzle it may be faster to retract these self-welding sleeves. With these Fluke multimeters, what has happened to me too often after using it as an ammeter, is to use it to measure a voltage without having moved the wires. The fuse must then be replaced.Thanks for all your sharing. You are doing a great job.
That's why some YT channels advise always changi9ng the leads back immediately after using it to measure amps. Don't rely on "checking before use".
@@russellhltn1396 This is the way.
That HP4262 is a thing of beauty on its own.
Thank you for all the efforts you do in sharing all these endeavours . ;)
@5:37 - it just goes to show that even with fancy equipment, technique and skill still reigns supreme.
I actually have an infrared heat tool from Raychem designed for installing those solder-shrink connectors. I picked it up at surplus for around $25 about ten years ago. Back then there were about $2000 new. Now they are only made on request and cost over $10,000!
Wow I didn’t even know they made such a thing…
Instead. Non insulated crimp terminals, and lined heat shrink. It is the most logical and superior repair. Crimp can be verified before it is sealed. Lined heat shrink can be any color you like, or clear.
I’m a happy user of gas-free 4-point crimped splices, aerospace-style. They are bare metal, just cover with a shrink tube of your fancy :) I’m not a fan of the solder-in-tube splices because they require very well prepared wire ends. That’s often hard to achieve in repairs. The solder-in-tube works great with fresh shiny copper. Anything less than that and it’ll pretend to work for some time than bail. I’m glad the folks at the Connections Museum had the wiring plant that was good enough to use those. When they work, they can save cost. But I’m still preferring the 4-point radial crimps. No need to worry about the wires stating in the middle of a splice or anything like that. And sometimes you can find them surplus in big quantities. Disclaimer: “sometimes” has been once a decade for me.
You need a capacitor leakage tester that can measure the leakage current at full working voltage so you can weed out faulty capacitors like in this PSU.
I recommend the HP 4350A, an old model but still very useful today.
Carlson super probe!
Oh, Dallas Semiconductor and that blasted internal battery!! Where I worked until 2010, we had an old 486DX33 that became support equipment. This computer had the problem of forgetting the hard drive settings, and that chip stored the information. The computer was setup for programming Allen-Bradley PLC2 programmable controllers. The software would not run in any emulation in Windows, and had to run pure MS-DOS 6.22. I had to hack into one of these to bypass the internal battery. I ended up cutting conductors and soldering wires connecting to a dual D cell battery holder. I used D cells because maintenance kept them in stock and there was room inside the steel PC case. The PC went to Mexico with all the rest of the equipment when that place closed.
Sheesh Master Ken would have spotted the mistake before you powered on and Eric would have fixed it with his finger thats what you get when you try to have all the fun alone 🙂
😂😂😂
So true. Master Ken would reverse engineer the zero reading to its source in a flash. But hey, it’s a comforting thought that even the master of faultfinding gets his wires crossed sometimes 😉
Thanks for the video, Marc. Now I know the correct replacement fan I need to buy for my own device. It's really a great PS, but I avoided to use it because of the noisy fan.
I just tried those splices for the first time to make some Christmas lights longer. They're outdoor rated and made the 60 splices pretty easy actually. Luckily that spt-1 wire has some pretty thick insulation so it didn't come close to melting. I was surprised
I have one of these and it's pretty awesome. I bought it since it was the only triple power supply I could find that has three fully isolated outputs. This lets you change which outputs are positive and negative, and there's relays in it that will let you series or parallel the 20V supplies to get more voltage or current. The other good thing is it's 100% stock parts. There's no custom chips or other parts except the main power transformer which is kind of weird for a tek product.
Actually made by GW Instek, along with many other Tek (and now Keithley) power supplies.
Hey i work at Tek! I love seeing these !
Keep up the good work!
it's always a crapacitor, this is exactly why I always replace ALL the caps in old gear even if they test OK... as like you experienced sometimes they breakdown when exposed to voltage.
The worst design fault of this supply is that the "Auto Sequence" button has "ON/OFF" silkscreened onto it, which makes it look identical to the Output ON/OFF button unless you're paying close attention to the far less obvious text printed above the button. On more than one occasion I've gone to turn off the output and hit the Auto Sequence button by mistake, which causes it to start stepping through all of the memories. I've never bothered to set these up and on mine they defaulted to the maximum voltage and current limits, so my circuit that I intend to be supplying with 3.3V suddenly gets hit with 20V and a 2.5A current limit. I definitely reccommend storing a low voltage/current into all of the memory slots so that accidentally pushing this button is not so destructive.
I'm afraid every time I turn mine on that the Dallas battery is going to be dead and the calibration wiped. So far it's still holding out... but one of these days I really need to pull it out and dump the contents at least before it dies. I think I've seen people make boards that replace the Dallas module with a microcontroller and FRAM (which, like core memory, needs no power to retain data), but last time I looked into it I couldn't remember which Dallas part specifically was in the supply to see if any of the existing designs were compatible. Thanks for your video which clearly shows the part number. (As you know, it's kind of a pain to disassemble).
When I take it apart again I'll do the fan mod as well-it is indeed quite loud.
when i worked as auto-electrician we used mini torches to melt the shrink connectors for watertight connections. Those torches also work as soldering guns, so would assume they would do the job to melt your solder connectors. They just require a little practice to not melt the other wires in a bundle. They're also quite cheap and still mass produced because they're also used in cooking
Half the reviews on brûlée torches are from electricians, hehe. Good shout!
Great Job Marc! Ah Yes... The Dallas "non volatile for awhile" RAM. :^)
That is a very nice solution for the output led "issue". Firstly it is probably what Tek should've done, and secondly it is easily reversible.
Great video! Thanks for posting. I have the same power supply and ran into the same issue a few weeks ago. You saved me so much trouble shooting time 😀. I ordered the new caps and fuses you recommended and I'm back in business. Thanks!!! I even had the same complaint about the loud fan so I swapped that too. Keep up the good work.
Excellent! That’s why I make the videos!
The red color filter in front of all those LED's is a bandpass-filter. It passes low frequencies (high wave-lengths) in the red spectrum and blocks everything else. Green (and yellow) are at higher frequencies and can therefore not pass that red filter. ;)
Nothing an incandescent bulb on top can't fix ;)
Nice, it was originally used in Maxtor ;) Long time ago bought by Seagate if I'm not mistaken.
Appears to have been made by GW Instek, along with many other Tek (and now Keithley) power supplies . . .
At least Tektronix had the foresight (and the budget?) to put fuses on the AC secondary. It might be a whole other kind of repair if they hadn't.
AFAIK it's mandatory in many countries. At least it used to be in Sweden.
I did like the solder splice, we used them in aircraft when I worked for manufacturers. There's a variant with a black pigtail wire that's very useful for grounding shielded wires.
Good call swapping out the fan. I need to do this to mine.
Those splices are great. They're used a lot in automotive wiring repairs.
Perhaps you could change the current limiting resistor for that LED, and "turbo charge" your replacement LED bar? I agree with you on wanting a clear "This is hot" indicator!
I've seen 0.1uF radial ceramic capacitors fail short. Actually many of them in the same lot of product. They were reasonably easy to find thermally.
From wikipedia:
The capacitor plague was a problem related to a higher-than-expected failure rate of non-solid aluminium electrolytic capacitors, between 1999 and 2007, especially those from some Taiwanese manufacturers,[1][2] due to faulty electrolyte composition that caused corrosion accompanied by gas generation, often rupturing the case of the capacitor from the build-up of pressure.
I too had bought the all-in-one sleeve and soldering. They are great for doing DIY and medium temperatures. But unfortunately when you do it in an engine bay the heat exceeds and the wires come on soldered. Very frustrating
The DS1220Y-200 is the same as in the HP3458A, CALRAM. It's still available, but check for cheapest version, like faster access and/or other supply voltage compliance.
Some day soon, I'll have to replace that in my 3458A again. So better do it soon, and don't forget to copy the content first, should not be as crucial as in the DMM.
You can actually still find most of the dallas backed up memories rtc. I replaced 2 recently on 286 motherboards.
Thanks for the tip, I did not know!
As an electronics engineer / electrician of over 35 years, I've never connected a piece of test equipment up incorrectly, put a component in the wrong way, not connected wires back up after fault finding, grabbed hold of high voltage capacitors that are charged up, let the magic smoke out.
Can any other engineers think of anything that I ''haven't'' done? 🤔
About to film the same video for one of my nice TTI power supplies that let out the smoke last week.
Upvote, it will be excellent, now let's watch this.
Nice repair! The Fluke is a good dmm, but I see it offered you some traps: it has no input jack alert, defaults to AC amps, to exit stand-by mode just press a random button...funny to watch, thanks!
Surprised the Connections Museum uses solder splices. Scotchloks are a telephone company favorite. My favorites for quick splices are AVX Poke-Home wire-to-wire connectors. They don't require a soldering iron, heat gun, or crimping tool. You just push the wires in.
I heard that you can still buy new replacement Dallas clock chips.
It might be a bit much trouble, but consider adding a circuit to flash the output indicator to help it stand out, then you can stay with red and get good illumination.
There's another youtuber on here who has made a replacement for the DALLAS module of death. That runs from normal replaceable coin cells and its a direct plug in replacement. He goes by the name necroware, might be worth reaching out.
Thanks for the tip! Oh I see, his is for the RTC part, not this one. But quite close and really well done, I could inspire myself from that.
@@CuriousMarc ah darn you're right! Apologies if its a dead end! Just saw the module and was like "wait I've seen this!".
I did reply but maybe it didn't post.. you can get an SRAM to FRAM adapter board already made from places like pcbway etc (or just make your own)
@@CuriousMarc FM1808 family of FRAMs may be a drop in replacement with some SO to DIP adapters.
Although the NVRAM ICs can still be bought, for many it is easy to carefully mill away the plastic over the connection to the internal battery, disconnect the IC from the dead battery and connect it to a pair of wires and a conveniently placed CR2032 cell. Since the datasheet shows no NC pins, I suspect they are below one of the narrow ends. I wonder if using a 28C16 might work as well, given that the DS1220 has no RTC.
No need to mill away the cover, it will pop off. Beware of poor soldering on the RAM pins near the edge of the PCB. We used those at 3Com and they were a constant quality headache. I would replace them with a mini PCB with RAM on the bottom and a CR2016 holder on the top.
A possible replacement for Dallas DS1220Y-200 is the DS1220AD-200+ from Maxim Integrated.
My HP8753D VNA stopped working a couple weeks ago. I've been putting off tearing into it but I suspect that the issue is in its power supply too. Hopefully just plague caps that fingers crossed haven't done lots of damage.
Very mundane question: what label maker did you use to make your little LED frame for the front panel?? I've been trying to find one that prints white text on a black background, and you seem to have found one!
It’s a humble Brother p-touch. I like it very much. But it’s a bit like HP ink, they get you on replacement label cartridge price…
Another nice thing about the P-touch is that you can get heat shrink on a spool, so labeling wires or bundles is easy (I _hate_ flags!)
One thing to note is they are sold by the flattened width of the tube (1/2 the circumference) _not_ the diameter it will fit over.
No! I've never done that before! Nor, especially, the other way... when that crazy fast expensive fuse blows... nope, not me.
Never happened to me either. This episode must be fake.
It has internal series/parallel relays, so you should have been able to put it in series mode and gotten the full 28V.
It does, but I needed the 3 supplies.
Hey I do enjoy your videos very much
Mark, Nice to see that you too are human.
Marc, what is the make/model of the workbench you are using in this video? I really like the depth of the shelf and working table underneath plus the monitor mount location.
That's an IAC Dimension 4 workbench. The Cadillac of modular workstations. $$$.
Excellent choice of fan, seems to make a surprising difference. I took a different approach and built a fan speed regulator for my vaguely similar GW/instek GPC-3020 . I'd post a link but YT usually flags it as spam - it's easy to find on my channel, or directly with video ID # 3FC4myguLyw .
I think I would have taken your approach too. Doubtless it is only noisy because it runs flat out all of the time. I would worry that a replacement might not provide as much airflow as the original, but I am sure that Marc has taken this into account.
In 40+ years repairing all sorts ive ever had an electrolic cap go short,leaky yes,short no.Tant caps,yes they do go short.
I encountered a shorted electrolytic cap recently. Zero ohms. Usually, they just blow up. This one was shorted but the 5 volt regulator current limit saved explosion.
@@buckykatnga I must of been lucky,,as you rightly say they go bang sometimes,which makes it difficult to know the cause,many PSU / Monitor repairs back in the 80,s had input caps blowing, because customer was forgetting to check if 110/240 switch was correctly set,auto switching was at an early stage.Many a new workshop engineer jumping,with clouds of smoke belowing from equipment LOL
That's because they don't usually have fuses on them and they burn open.
this man is wearing a Chopard at works
It’s a quality watch - in-line with the quality equipment he has in the workshop - not unsurprising…
I would like to see a video on controlling the HP3438A DVM over HPIB..
I am designing a esp32 to HPIB interface that I hope to use with it...
I would also like to do the same with power supplies and other lab equipment..
Especially that NASA NIXIE frequency counter... Turn it into an universal display for everything numerical...
Have you tried using a laser engraver to excavate the batteries out of those black epoxy packages?
You have my dream job! 😁
Any concern that the quieter fan might not deliver enough cooling air?
Very unlikely. The old fan must have had worn out bearings in it and that's why it was so noisy, I guess.
Yes, you have to choose one with enough flow and static pressure. That’s why I couldn’t go with the really low noise ones. But at least this one I can live with.
5 for $14 ! Dommage. Bon en même temps... ça se comprend.
Mais merci pour une vidéo de plus qu'on savoure à chaque instant.
So folks, if you see Marc in the wild (real world) don't cheer too loud.. or he might try to replace you.
He doesn't like noisy fans....
Lol 😂
If your Dallas chip has become useless anyway, no risk to try Dremeling the top off and prying the old batteries out and soldering on a new button cell holder. If you have access to a milling machine, that might be a safer way, take a few tenths of a mil off with each pass.
Not sure if the new fan is a good idea...
I'm pretty sure they chose the loud one for a good reason. I have done similar mods, and most of the time the device got significantly hotter with a silent fan.
You have to buy one with the correct flow and static pressure. Which is why I could not go with a truly low noise one. This one is just less obnoxious…
It's an electrical Christmas comedy, Ha ha, merry Christmas
Just replace the fuses with thick pieces of wire. You know, like back in the day when homes had those screw-in fuses and people would put a penny in the fuse socket and screw in the fuse on top of it to hold it in place. That'll get the power flowing again. I'm sure it's perfectly safe... 😉😂
I'd check out Noctua for a silent fan manufacturer.
Bad cap, bad cap, whatcha gonna do when Marc comes for you?
Marc - if you find a good solution for the DS1220Y part please let us all know...I did see another comment lower that talks about the DS1220 and will investigate that as well. Have two old HAL ST-8000 TU's that I replaced long ago and I'm sure are DOA by now. 73 - Dino KLØS
Mark my Fluke 87 series 5 tells me I am a dumb dumb when I forget to move the leads, surprised that the 177 does not.
I’m surprised too! The blue Tek meter certainty does complain about it. If you look at the footage closely, the Fluke flashes “Lead” for maybe a second, but then it goes away. Maybe the lead detection microswitch is not working correctly anymore?
Have you guys ever blown a power supply by putting two in series? It has happened to me at least twice. However when I connected them in parallel and then I use one's current limit, nothing happened. Do you guys have any explanation for this?
Are the outputs referenced to ground? Any other connections to the power supplies that might reference to ground?
@@ChrisSmith-tc4dfdefinitely not. The negative of each ps was isolated from the main ground wire. Usually there is a piece of metal connector negative to ground. I have removed them all. Besides, if the negatives were connected to ground, one of the ps would have been short circuited.
Probably a power supply whose design was not thoroughly tested in series operation. Even a few HP supplies get damaged when you back-drive the inputs, and series operation is exactly that.
So, explanation: supply not good enough.
Time to purchase a Power Sink
What is the source of those meter probes with clip-ends ?
Probe Master (eBay, Amazon, etc...)
flashing led?
Why not cut the red filter just around the output LED spot??? a green LED for that op with be nice!
That's what I'd have done as well, but the downside is that you can never return the equipment to 'as new' configuration.
I guess that display filter blocks all colors except for red. I would have thought the bright green LED would work at least a little bit. Not seeing the green and yellow was unexpected.
That's how filters generally work. That's why a red filter is red. I have a ridiculous surge protector with neon bulbs to indicate status, and one has a red filter, the other has a green filter. Good luck ever seeing the neon under the green filter.
You can wake up the fluke meter by pressing one of its buttons by the way :)
What is the tool you’re using to desolder so easily
That is the Hakko FR-301 Desoldering Tool
Maxed out the PS2521G? I think you want a HP 6623A. I happen to have a spare one in the SF Bay Area.
The HP 6623A is a nice triple supply, but only 80W and lower voltage. This one is 250W in a much smaller form factor.
@@CuriousMarc The form factor of the PS2521G is certainly much more bench friendly. If I found the right specifications, it however outputs "only" 5A @6V + two times 2.5A @20V for a total of 130W (output). The 6623A is meant for unsupervised industrial applications in a standard 19" rack and outputs up to two times 40W (2A @20V or 0.8A @50V) plus one time 80W (up to 10A @7V or 4A @20V) for a total of 160W. It has an awfully loud fan though😆
@@guntherthomsen3864 Alright HP wins!
Ground fault?
I feel that an ESR Meter would have saved you a lot of time fault finding that PCB.
That’s the weird thing. As you can see in the video, all the bad caps tested good for ESR! Really a very unusual cap failure.
@@CuriousMarc Sorry. I assumed you hadn't checked the ESR as I'd check the ESR of the caps in circuit. Your ESR meter is slightly better than mine. 😉
It would have been a Fluke if you got the expected readings!
kool
It's never the electrolytic caps... until it is..
Fun
Did I hear you say crapacitors?
Multiple shorted electros. Very rare. Certainly seems like a bad batch
Did you call them Crapacitors ? 😂
That’s what they are called, says the dikchionarry
Hi!
OO do I hate those solder splices. Don't start using them now! lol
crimp splices are nice and fast
Trying to measure current with the leads in the wrong connections is a real doodly-doo...
Fuses add unreliability to a system.
Fuses let you trade reliability for reduced destructive potential.
First?
Yes! You get awarded a replacement Rubicon cap, but still in 360p resolution.