@BowWowPewPewCQ my name is Paul. I am watching MikesRadioRepair UA-cam video to really put my best foot forward and put in an honest effort to learning about testing two radios. At approximately 8:32 I hear that the "left terminal of the mosfet is connected to ground or the ground plane and the lead is sort of hovered over that area of what looks like to me as the "circuit board" okay, so, since I am not sure if the brand of CB transceiver I will be working on will have the same final transistor or not, in other words I am trying to say "how would I now for sure, when working on another but similar chassis that the same place on the circuit board is ground or ground place area, they look quite similar but they all seem to work a little bit different" Do you think that it is okay if I send MiesRadioRepair an email asking a question to this effect? cause I really want to get a making noticeable performance improvements! One thing I was thinking is that maybe, if I get a toll free 1-800 number from an owner's manual I can call directly and ask questions to someone who answers the telephone call.? Maybe it is great because they may know that particular brand and they can walk me through it such that I can see and hear ally noticeable results. I don't mean to like make the volume go so loud that it is obnoxious or it disturbs everyone in the community and so forth but I guess what I am trying to say is or the word I am trying to get it is that I have a sense of accomplishment from working the CB radio and that the the other are on the channel or band notice a difference! I am not sure how to express it otherwise. Once upon a time I was in a shop in Buffalo New York America and I could here a very noticeable difference and big signal out of an amateur radio once, I guess i will call the shop keeper worked on the radio. Really big signal readings on the S/RF meter and loud volume. i partially get scarred when the signal are really loud out of the speaker when I am by myself like I will get in trouble for disturbing people, but I do not wat to do that, that is not my intent. I guess I sort of want a purpose, it is funny why would I think about "performance improvements" I think that way equipment is manufactured and made is really great the way that it is!!! However, I think that deep inside I could contribute to radio gear and such. Well I thought I would just run this buy you and I will send the same thing to MikesRadioRepair in the email that I see the best I can in UA-cam.😀🧑🔧🐾🐿🌎🏁
Mike is absolutely the best Tech ! Old school sense and more importantly knowledge, and he is genuinely a cool guy. My unending problem is how in the world does a person, potential customer contact him ??? any help here would be monumental !! Thanks !
Forget it. He quit responding entirely. I was a frequent customer and he repaired several radios for me. Then he quit responding and no one has been able to contact him.
Thanks Mike for all your videos and help! I installed new mosfets and ran into a problem on AM with the Lincoln II plus and just a few minutes before finishing your vid I found a blown Tip36 lol!! I was lucky with the ferrite as all I had to do was tack it back in place. Thanks again!!
I guess im randomly asking but does any of you know a tool to log back into an instagram account? I was stupid forgot the login password. I love any help you can give me.
@Cade Thomas I really appreciate your reply. I got to the site thru google and I'm in the hacking process now. Looks like it's gonna take quite some time so I will get back to you later when my account password hopefully is recovered.
On my Lincoln 2+ I moved my AM regulator to the back where the heat sink is. When it was on the side, it would get hot hast. I put a new Tip-36 on the back and it’s night and day difference. The regulator and the finals run nice and cool. That was about 2 years ago. No problem since.
Thanks Mike for addressing the Maxima mod. There is a certain UA-cam or self-proclaimed CB guru that preaches the radios gnocchi up without the max mod and I’ve always thought he was full of BS so I appreciate your addressing that with a commonsense approach.
Good crash course on radio electronics. I wish I had the attention span to learn electrical engineering. I would have a lot of old electronics that would be virtually immortal.
I have noticed several videos on blown finals. Many of the videos involve the President Lincoln II. I recently acquired a Lincoln II. Guess what? I blew the finals out. I've been into radio's for 20+ years and never ruined a radio. My swr was 1:4 and I have current chokes in line at the radio, shack entrance and at the antenna. My Lincoln had the 1310n transistors. I shipped it off and I was advised to go with better transistors.
I have always known about the SWR since I started using the radio, however I never knew exactly what finals were. I definitely learned something here. Thanks
A 1 to 1 baulin in the coax can also prevent a lot of the SWR from getting back into the radio because it acts as a reflexive point that will bounce a large part of the reflected power from the antenna back to the antenna.. Is it a substitute for a good matched antenna? NO but it can help a marginal antenna from becoming a bad antenna.. There are lots of conditions that can detune an antenna like heavy rain, ice, fog etc. that are temporary but if you use your radio in those conditions often it is something to think about.. several wraps of coax thru a ferrite core can get you there..
I did radio years ago.... Please note that you can tune your antenna on a specific channel. If you set it on channel 40, channel one will probably be higher. The best spectrum spread is to tune on channel 19 or 20. this is why truckers run channel 19.
what shit are you talking about ?? so why don't truckers run on 20 if that's your logic.. in fact if you take in to account the 'alpha channels truckers would use channel 22 or 23 as center of the CB spectrum 26.965 to 27.405 is channel 22.5 or 27.230Mhz. run on channel 19....ass..
Compare the lowest channel, 1, against the highest, either 23 or 40. Adjust the antenna(s) accordingly. Adjust dual antennas at the same time, not individually.
ALWAYS TUNE YOUR ANTENNA BEFORE PUTTING A RADIO IN SERVICE. Never trust the internal SWR circuitry. It lies, it lies and it lies. Use a good external SWR meter. One that has not been dropped and broken the solder connection inside of the box. 25 - $55.
I had the same issue with a stryker 655 a guy brought in the shop and he actually admitted his antenna was bad. When it went took out the finals and tip36.
Why does everyone who know a little bit, like to dis a guy who makes a video for those that don’t know this? Be nice or be quiet and click on another video. Thank you for the video and the time you spent for some.
Question about the finals, I know that the 2sc1969's would need to be a matched pair, but do mosfets for example, irf520's need to be a matched pair? I'm still learning all this stuff, thanks.
I have a friend who checks his SWR off the radio and it is great. He is a ham operator and when he runs an amplifier it shows a much higher SWR. Should he be concerned or disregard the reading and only go by the. "barefoot" reading?
Yes, he should be concerned. When you are running a amplifier you need to place a SWR meter in two places, between the radio and amplifier and another between the amplifier and the antenna.
Can the method you used to check the final be used on older radios? I've got a Robyn SB 520D with weak (if any) tx output. I didn't see any other damage. Would it be a good idea to replace the AM regulator also?
I have a K40 trunk lip Mount antenna hooked up to my Stryker 447 radio and my SWR on it on Channel 1 is 1.1 and on channel 20 is a 1.2 and on channel 40 is a 1.7 but for some reason I can't hear anybody on it for some reason and I live really close to the highway where there's tons of semi trucks rolling down it but I still can't hear anybody talking could that mean that my antenna has something wrong with it
SOUL MAN, it sounds like you have the exact same issue that I have with my Stryker 955HP. Years ago I used it while driving tractor-trailer and had a few occasions where SWR peaked to the limit due to bad antenna connection. Not sure if that was the cause, but the last year I used it & ever since, I can't receive nearly anything on that radio even tho I'm in an area by the highway there should be plenty of CB activity. I just hooked it back up this week and it's still 'far too quiet'.
@@ColtTSMG I figured out what was wrong with my Stryker Sr 447 my antenna is a trunk lip Mount K40 antenna and it wasn't grounded right but then I got it grounded right and it works great now I'm receiving and transmitting very good and they SWR is down to a 1.1 on all the channels and on Channel 40 it is 1.2 my SWR is now so I'm receiving good and transmitting but I'm still upgrading my antenna to a striker Sr A10 antenna I already ordered one but the u.s. Postal Service lost mining during shipping so now I'm waiting on the US Postal Service to replacement hopefully they are send me a new one other than that my radio is working out great now so you might want to check and make sure that your antenna is grounded cuz that could be your issue as well
Good work ..👍thank you for the video .../// my mike is burn ..the cause false connection 🥺on my president jackson ..40 chanel...inf/sup etc but my square microphone don't answer ..i got to repair it...i slowly learn...
Any repair tips for fixing a STANDARD ECLIPSE GX1245S VHF Marine radio? Current draw is 600 mAmp. Display is blank but the illumination light is lit. Haven't been able to locate a schematic. Service manual is MMGX1240S (covers GX1240/1245 models ). Thank you for any info you may provide.
I have a RK5640a running a Wilson 2000 on a 18 ft Wilson cable running for a few years w/0 SWR all the sudden it started crackling when receiving transmissions but I was able to transmit fine two days ago it just stopped receiving and transmitting all together thought cheap radio lasted longer than I expected however now I've installed two brand new radios both same issue seems when I go to calibrate it starts working normally and then the needle shoots back and forth a few times and then down to nothing no response the rx/tx lights up antenna lights off and no responses from the R/RF,SWR,CAL settings I'm puzzled could it be a bad antenna/cable killing these radios?
Yes it could. You may have a intermittent short. If the coax cable is routed through a door jamb the cable may have become crushed. Depending on what type of antenna you have I have seen loading coils fill up with water.
Unknown, that's not enough information. The SWR curve usually looks like a spread out U or high SWR on either side of the resonant point. Measure the SWR on channel 1, 20 and 40 and take readings. Remember that as you go up in channels you are going up in frequency. Higher frequency means shorter wavelength and thereby a shorter antenna. Lower in frequency means longer wavelength and thereby a longer antenna. So if you have a lower SWR on channel 1 than on 40 shortening the antenna would shift the resonant point to the higher channel / frequency. If you have a lower SWR on channel 40 than on 1 lengthening the antenna would shift the resonant point to the lower channel / frequency.
I don't have a schematic for it, own one and have never worked on one but if the final is bad that's probably all it needs. I would probably probe around with a oscilloscope first to verify it's the problem and if it is take some voltage measurements. Basic troubleshooting.
There is a project but to see the signal strength that the radio is receiving, for example, a weak but audible international station lights up 2 LEDs and one is coming in strong as if it were local, lights up 5 LEDs for a radio receiver. Do you know or have a project like this?
Had that experience. Basically, I've burned the output stage of an RF PA that I've made, due to a badly tuned antenna. Funnily, the PA is only capable of outputting 1W at best, and I was not expecting it to be damaged.
Mike, I have a dual band amateur radio I picked up second hand from another ham who said the UHF side of the radio no longer worked due to a shorted N to SO239 adapter. The radio still works fine on VHF and receives UHF fine. With an analog watt meter into a dummy load, I can see the needle just barely lift off 0 while in low power UHF, but if I key the radio on high power it blows the 15 amp inline fuse before I can see anything happen. Do you think replacing the Mitsubishi ra60h3847m1 PA module would potentially fix this radio or has more damage been done that I cannot properly diagnose or detect? I am having a hard time finding any information about testing PA modules and was hoping to find a way to test with a multi meter like you show in the video. RF in, Gate voltage and Drain voltage all short to ground with high resistance while RF out does not short at all and the meter reads OL. Is that a sign that the finals have fail and are no longer letting RF through the PA module? Any help or comments would be greatly appreciated.
I’m having problems with my SWR high it goes to three no matter which way I put it on channel 1- through 40 still stays the same three I can’t get it down I checked the coax coax is fine the ground it’s fine but how can you tell if the antenna I have a trucker 2000 I’m thinking he’s got some kind of a gram problems on the van I have it on the van back of the van
@@mikesradiorepair np Mike! I know you're busy, I just want to say thanks for your detailed videos. From reading schematics to using test equipment, I've learned a lot just watching. One of these days I'll own the essential pieces of test equipment so I can maintain my collection of radios. (70's-90's) Just for alignments.
I had some serious damage done to my Anytone 5555N it have 3x 13n10 but the board looks the same as yours, the TIP36S was burning hot even when not transmitting, it just happend a morning i turned on the radio while i key the mike the display got dim and the radio basicly turned of untill you released the button. It even melted the fuseholder. I saw some one talk about those 13n10 are bad, and recommend to replace them with IRF520's - anything else to replace?
Mike, thank you for the videos, they're so helpful. Just curious, can you test the AM regulators and the drivers the same way you tested the finals? I'm trying to find out why a Cobra 25 LTD Classic won't transmit or receive. (I already checked the cb/pa switch and caps esr.) The sound chip makes noise when I put my finger on it. The signal meter isn't moving, but it's not "stuck", it moves freely - doesn't move when receiving signal is being broadcast. In the rear of the 25 there are two transistors. The one near L12 is the final, but what is the one in the very rear corner and what is the one by the volume/on/off switch? Thanks!!
When you say does not transmit, you mean you have a dead key but no audio ?? The audio chip on the side of the chassis might be your issue. The 29 and the 25 radios DO require those 2 thick rubber washers between the mount bracket and the case of the radio.... If their not in there then when you tighten the 2 knobs they pull the case away from the PCB slightly and the solder joints fail.... Example no receive in the speaker and no audio going out....I have seen that a few thousand times....
@@cajuncoinhunter Thank you for writing back. If you watch this video someone posted, this is exactly what happens with my Cobra 25 LTD...it's easier to watch his video than me trying to explain it, but everything that happens in his video is what happens with my 25 LTD...here's the link for you: ua-cam.com/video/nzqjIKUKBsg/v-deo.html
Mike, are there different SWR meters for different bands, or are they all the same? I have one that I used for my CB, will that work with my Marine VHF?
No, they are not the same. You would need to look at the specification sheet for the meter you have but most meters used on the amateur radio HF bands and on CB only cover up to 30MHz and maybe a little higher.
Just a reminder to those who make their own coax cables: Coax, (especially the foam core), can suck in water like a fish. It's amazing how much water can wick into your cable if it's not properly sealed. You can generally tell this is happening if your SWR is good on a dry day and they goes wonky after it rains. Then it dries out and your SWR is good again. Chances are you have water in the line or your antenna itself has some water intrusion somewhere. So make sure your antenna system is SEALED. The coax is overlooked and skimped on 99.9% of the time. Waterproof all connectors. You can use Mastic tape on connections you may want to remove later. Just make sure and SEAL it. Also routing your cable out of the direct weather is a good idea (under your house eave, car hoods, etc). Little exposure as possible. For underground runs, I put mine inside electrical-grade conduit for extra protection. A little extra work and expense, but It's cheap insurance. It also helps if you find yourself digging later around your coax. You'll hit the conduit first and not damage your coax. I also like to use heat shrink (the type with the glue inside) to seal where the coax enters the connector. I don't rely on the solder alone for sealing. Get GOOD GRADE heat shrink. Not that cheap Rat-Shack, Harbor Freight thin garbage. Get the 2 or 3:1 stuff with the heavy glue. This stuff will seal just about anything. Likewise it's tough to remove so be sure your solder and coax tests out OK before you install the shrink.
I remember years ago, operators stating that their match would improve in the rain. I never tried to disprove or prove that because I never gave it much thought. Recently I have learned the importance of sealing the coax and the connection that faces the weather on a daily and nightly basis.
Self amalgamating tape is is good also, especially if you live in a area with destructive birds that like chewing on coax ends. Though usually they are that particular, gotta chew it all in some parts of the world.
Ideally your coax cable shouldn't effect your SWR. It's a 50 ohm transmission line. However if your coax cable has poorly installed connectors, has had water intrusion into the jacket or has become kinked or smashed that can greatly effect the impedance of the coax cable which in turn would manifest as a higher SWR. The big difference between grades and the diameter of the cable is the loss. Larger diameter and higher grade coax cables have less loss meaning more of your TX power actually makes it to the antenna and on RX more of that signal makes it to the receiver in your radio. The big advantage of working in the HF range of frequencies is you don't need to get crazy with extremely large diameter coax. Loss doesn't become a big factor until you get into the UHF range or higher. Personally most of my HF antennas with runs under 100 feet I use LMR240, over 100 feet I use LMR400. At UHF frequencies I use LMR 400 for shorter runs and LMR-600 or 7/8" hardline for longer runs. My microwave antennas have at a minimum 7/8" hard line with most being fed with 1 5/8" hard line.
I have a galaxy 33hml and I checked from the ground on the transistor to the opposite side and had continuity between them on both and it didn’t matter which lead I used on the ground but there was no continuity from ground to the middle of the transistor. Does that sound burnt to you?
I love your videos. I learn a lot about radio from watching your content, thank you. Question - if the finals get blown so frequently, and pass on current for more internal damage... shouldn’t they build in a fuse?
Hello there, Yesterday we had a snow storm and i heard a (tik tik) poping sound coming from my coax . I was not transmitting with the radio. this morning i turn the radio on it receive ok but when i puch the PTT, no modulation indicator an all mods. what could be the source of that poping sound and could my radio be fixed. any idea ? Same radio President Lincoln II thanks
That doesn't sound good. Lightning storms, snow storms and sand storms can all cause ESD damage. Every snow flake that hits a antenna can deposit a small static charge and that charge builds up. Eventually the potential gets large enough it can arc over and unfortunately it sounds like it arced over inside your radio. It's hard to take a guess as to what got damaged. You would need to trace out the PTT switching circuit.
Hi mike, I set up a 148gtl and my swr on the radio is high!. I put a mjf antenna tuner between the radio and the antenna. The meter on the tuner is down to 1.1 but still high on the radio. Should I disregard the reading on the radio?. Thanks in advance, Ernie.
I have a Cobra 29 soundtracker in my truck and I recently put speakers headlamps in my truck and now my RF reflection is really high how do I get it back down
In you professional opinion. I have an old Cobra 40 channel cb, LTD I think it was, that I used for 20 + years trucking. I spent over 35 years OTR & this was my 3rd radio. It has been boxed away for a dozen years or so. Are these worth going through, checking out & repairing if need be or is it better to buy something new. Just want to put it in my pickup just to have when I am on the road with my horses. Also I live on top of a mountain so I would like to see if it is like it was years ago where you hit the skip & could talk a long ways off. Just something to have some fun with. Also thought about hooking a linear to it. What's a good antenna these days? I always liked the K40's but didn't know if anything else is better. If I do what I am thinking of it will be mounted in a Dodge pickup. Thanks for your time.
Mike can you tell me can you tell me if the a.m. regulator would have anything to do with me mod fading out on the FM frequency after about 20 seconds it goes right back signal stays good but the mods fades out on the FM band I am in the UK and the radio is a Stryker sr955.thinks
Great job as always Mike. Just curious if those finals were good what would the foward and reverse resistance be? Thank you for sharing your info on radio repair!
That's exactly what I was looking for in the comment section...what the reading would be had the finals not blown? Please let us know! Thanks again Mike for sharing your knowledge with us! Brian
It's not horrible if that's what your asking. With a SWR of 1.5 you are transmitting 96% of your power and 4% is being reflected back to the radio. Start to get worried when you get near 2.0 to 1 SWR. With a SWR of 2 you are transmitting 88.9% of your power and 11.1% is being reflected back to the radio. At those levels and above you start to risk damaging the output section of the radio.
MikesRadioRepair my swr usually is at 1.5 dead key at like 50 watts and then jumps up to around like 1.6ish when modulated is that bad 😬 and thx for the reply
Mike, Good video...If the final has been replaced in a cobra 29 Ltd classic and still doesn't work, and let's say the regulator is also blown. What will the symptoms be for such a problem. Would the radio fail to key up ? By the way the driver has also been replaced along with the audio chip. Thanks, Billy
I'm trying to set up a really old set , Midland . 50ohms impedence ? Hmm , I've heard that be fore . Impedence is resistance . But you still need a opposite polarity reflecter for antanna to work ( I think) . Just don't short it . Broken coax . Splices will cause problems too .
Now, if I could make heads or tails of my switching power supply layout vs. schematics to fix it. It blew out the mosfets... strange because it is supposed to have overheat, over current, over voltage protection, but when doing testing using it, it overheated and did puff the magic dragon on me. I have replaced those, but the supply is stuck in protection mode, and I'm at an impasse. Alinco DM330MVT
I had a lighting strike one of the antennas that I had up. I had my ham radio unhooked. but I had a free play radio and a am drake which both got hit by the lighting. magic smoke came out of the drake. still got it around here some where. after it killed those two radios. it by passed the big screen i had bought was fine but it went on past and fried the misses computer. go figure.
Hi Mike, really enjoyed that video. I have the same radio and it's the first time I've seen what it looks like inside. Mine get's so hot where that regulator is, the case is almost too hot to touch if I run the rig above 5 watts - the finals heat sync never gets warm so I suppose that's a good thing? Is the heat normal for these radio's?
After just watching a video claiming this can't happen it was refreshing to come back to reality. Great explanation.
@BowWowPewPewCQ my name is Paul. I am watching MikesRadioRepair UA-cam video to really put my best foot forward and put in an honest effort to learning about testing two radios. At approximately 8:32 I hear that the "left terminal of the mosfet is connected to ground or the ground plane and the lead is sort of hovered over that area of what looks like to me as the "circuit board" okay, so, since I am not sure if the brand of CB transceiver I will be working on will have the same final transistor or not, in other words I am trying to say "how would I now for sure, when working on another but similar chassis that the same place on the circuit board is ground or ground place area, they look quite similar but they all seem to work a little bit different" Do you think that it is okay if I send MiesRadioRepair an email asking a question to this effect? cause I really want to get a making noticeable performance improvements! One thing I was thinking is that maybe, if I get a toll free 1-800 number from an owner's manual I can call directly and ask questions to someone who answers the telephone call.? Maybe it is great because they may know that particular brand and they can walk me through it such that I can see and hear ally noticeable results. I don't mean to like make the volume go so loud that it is obnoxious or it disturbs everyone in the community and so forth but I guess what I am trying to say is or the word I am trying to get it is that I have a sense of accomplishment from working the CB radio and that the the other are on the channel or band notice a difference! I am not sure how to express it otherwise. Once upon a time I was in a shop in Buffalo New York America and I could here a very noticeable difference and big signal out of an amateur radio once, I guess i will call the shop keeper worked on the radio. Really big signal readings on the S/RF meter and loud volume. i partially get scarred when the signal are really loud out of the speaker when I am by myself like I will get in trouble for disturbing people, but I do not wat to do that, that is not my intent. I guess I sort of want a purpose, it is funny why would I think about "performance improvements" I think that way equipment is manufactured and made is really great the way that it is!!! However, I think that deep inside I could contribute to radio gear and such. Well I thought I would just run this buy you and I will send the same thing to MikesRadioRepair in the email that I see the best I can in UA-cam.😀🧑🔧🐾🐿🌎🏁
Sure miss you real banter and no BS chat Mike, hope you are well and enjoying life.
Care sent.
Hey there. This may be a shot in the dark but, can you tell me the proper avenue to contact Mike??
No one , and I mean no one knows.😢 thanks. Mark.
Mike is absolutely the best Tech ! Old school sense and more importantly knowledge,
and he is genuinely a cool guy.
My unending problem is how in the world does a person, potential customer contact him ??? any help here would be monumental !! Thanks !
Forget it. He quit responding entirely. I was a frequent customer and he repaired several radios for me. Then he quit responding and no one has been able to contact him.
Thanks Mike for all your videos and help! I installed new mosfets and ran into a problem on AM with the Lincoln II plus and just a few minutes before finishing your vid I found a blown Tip36 lol!! I was lucky with the ferrite as all I had to do was tack it back in place.
Thanks again!!
I guess im randomly asking but does any of you know a tool to log back into an instagram account?
I was stupid forgot the login password. I love any help you can give me.
@Spencer Alfredo Instablaster :)
@Cade Thomas I really appreciate your reply. I got to the site thru google and I'm in the hacking process now.
Looks like it's gonna take quite some time so I will get back to you later when my account password hopefully is recovered.
@Spencer Alfredo You are welcome :D
My grandfather liked black walnuts. He used his workshop vice to open them.😅
I love your videos and greatful you take the time to explain what you do and why you do it. Cheers, 73's!
High swr on Lincolns or any radio with high watts Could be with cheap finals, 💥!! You are a good radio guy!!
Thinks Mike for the great information. That first part was nuts ! No max mod for me. Thanks!
Love your humour Mike.
I drew inspiration from your method for how I publish my How-to- Fix videos.
I'll trust MikesRadioRepair he's pretty good this guy is expert on radios just don't rush him.
On my Lincoln 2+ I moved my AM regulator to the back where the heat sink is. When it was on the side, it would get hot hast. I put a new Tip-36 on the back and it’s night and day difference. The regulator and the finals run nice and cool. That was about 2 years ago. No problem since.
Thanks Mike for addressing the Maxima mod. There is a certain UA-cam or self-proclaimed CB guru that preaches the radios gnocchi up without the max mod and I’ve always thought he was full of BS so I appreciate your addressing that with a commonsense approach.
Thanks Max Mike! You at least tried to teach some of us to work on our stuff! 😃
Good crash course on radio electronics. I wish I had the attention span to learn electrical engineering. I would have a lot of old electronics that would be virtually immortal.
Thanks for the video Mike great info.
I have noticed several videos on blown finals. Many of the videos involve the President Lincoln II. I recently acquired a Lincoln II. Guess what? I blew the finals out. I've been into radio's for 20+ years and never ruined a radio. My swr was 1:4 and I have current chokes in line at the radio, shack entrance and at the antenna. My Lincoln had the 1310n transistors. I shipped it off and I was advised to go with better transistors.
I have always known about the SWR since I started using the radio, however I never knew exactly what finals were. I definitely learned something here. Thanks
Were is mike ???, he is needed !!!!!
The price of repairing both radios was still less than half of what a new radio would cost.
Good to see you are still around on the platform, Mike.
Mike, how are you ? No radio repair? Please answer ! Fhanks!
Very useful Tips.
I wish you lived in the Uk, I have a High Gain 5 I really need tuned and setup.
It works, and had the channel Mods done on it.
Hi poss may be able to help with sorting your Hygain 5 radio
Can e mail me on mrianjones@live.co.uk
Good Advice.......Customer wanted "Fars" but only got "Swrs" !!! ......Whoever messes with Coax or Antenna better check Reflected Power.....
Thanks for letting people know about the Max Mod ripoff! I've been trying to tell people for years about that scam. Well done!
Thanks for these videos Mike, i have learned a lot. Going through them again, i think i missed a couple of them.
Very nice shared ideas that helps...!
A 1 to 1 baulin in the coax can also prevent a lot of the SWR from getting back into the radio because it acts as a reflexive point that will bounce a large part of the reflected power from the antenna back to the antenna.. Is it a substitute for a good matched antenna? NO but it can help a marginal antenna from becoming a bad antenna.. There are lots of conditions that can detune an antenna like heavy rain, ice, fog etc. that are temporary but if you use your radio in those conditions often it is something to think about.. several wraps of coax thru a ferrite core can get you there..
I did radio years ago.... Please note that you can tune your antenna on a specific channel. If you set it on channel 40, channel one will probably be higher. The best spectrum spread is to tune on channel 19 or 20. this is why truckers run channel 19.
what shit are you talking about ??
so why don't truckers run on 20 if that's your logic..
in fact if you take in to account the 'alpha channels truckers would use channel 22 or 23 as center of the CB spectrum 26.965 to 27.405 is channel 22.5 or 27.230Mhz.
run on channel 19....ass..
They ran 19 back when it was only 23 channels. 11 was a calling frequency, and of course, 9 was for emergencies.
That's probably why 9 was for emergencies because it was a mid spectrum channel when they were 23 channel
Compare the lowest channel, 1, against the highest, either 23 or 40. Adjust the antenna(s) accordingly. Adjust dual antennas at the same time, not individually.
ALWAYS TUNE YOUR ANTENNA BEFORE PUTTING A RADIO IN SERVICE. Never trust the internal SWR circuitry. It lies, it lies and it lies. Use a good external SWR meter. One that has not been dropped and broken the solder connection inside of the box. 25 - $55.
Your video's are excellent and very informative.
Alan in the UK
I had the same issue with a stryker 655 a guy brought in the shop and he actually admitted his antenna was bad. When it went took out the finals and tip36.
What are the best antennas for this type radio?
@@justbeforethereturnofchris2393 CB antenna!
@@PeterDad60 .....yea I found one that works with this CB radio...
I love your ability to teach me radio repair you explain it I understand it ! ps Im an auto obd tech my nails look worse than yours!
Why does everyone who know a little bit, like to dis a guy who makes a video for those that don’t know this?
Be nice or be quiet and click on another video.
Thank you for the video and the time you spent for some.
Maybe they think the info is incorrect
Thank you for your sage advice
I love it good
Keep uploading videos like this
Great TIPs Mike. No pun intended.
Question about the finals, I know that the 2sc1969's would need to be a matched pair, but do mosfets for example, irf520's need to be a matched pair? I'm still learning all this stuff, thanks.
Yes they do.
I have a friend who checks his SWR off the radio and it is great. He is a ham operator and when he runs an amplifier it shows a much higher SWR. Should he be concerned or disregard the reading and only go by the. "barefoot" reading?
Yes, he should be concerned. When you are running a amplifier you need to place a SWR meter in two places, between the radio and amplifier and another between the amplifier and the antenna.
Ok. Thank you I'll tell him!
Can the method you used to check the final be used on older radios? I've got a Robyn SB 520D with weak (if any) tx output. I didn't see any other damage. Would it be a good idea to replace the AM regulator also?
Which mosfets do you like to use for replacements? I see some TIP36C from galco but looking for the FQP13N10 mosfets and there are so many options.
I have a K40 trunk lip Mount antenna hooked up to my Stryker 447 radio and my SWR on it on Channel 1 is 1.1 and on channel 20 is a 1.2 and on channel 40 is a 1.7 but for some reason I can't hear anybody on it for some reason and I live really close to the highway where there's tons of semi trucks rolling down it but I still can't hear anybody talking could that mean that my antenna has something wrong with it
SOUL MAN, it sounds like you have the exact same issue that I have with my Stryker 955HP.
Years ago I used it while driving tractor-trailer and had a few occasions where SWR peaked to the limit due to bad antenna connection. Not sure if that was the cause, but the last year I used it & ever since, I can't receive nearly anything on that radio even tho I'm in an area by the highway there should be plenty of CB activity. I just hooked it back up this week and it's still 'far too quiet'.
@@ColtTSMG I figured out what was wrong with my Stryker Sr 447 my antenna is a trunk lip Mount K40 antenna and it wasn't grounded right but then I got it grounded right and it works great now I'm receiving and transmitting very good and they SWR is down to a 1.1 on all the channels and on Channel 40 it is 1.2 my SWR is now so I'm receiving good and transmitting but I'm still upgrading my antenna to a striker Sr A10 antenna I already ordered one but the u.s. Postal Service lost mining during shipping so now I'm waiting on the US Postal Service to replacement hopefully they are send me a new one other than that my radio is working out great now so you might want to check and make sure that your antenna is grounded cuz that could be your issue as well
Good work ..👍thank you for the video .../// my mike is burn ..the cause false connection 🥺on my president jackson ..40 chanel...inf/sup etc but my square microphone don't answer ..i got to repair it...i slowly learn...
any thing over three . start checking the antenna or coax.. one point five you can live with one to one is best.
Any repair tips for fixing a STANDARD ECLIPSE GX1245S VHF Marine radio? Current draw is 600 mAmp. Display is blank but the illumination light is lit. Haven't been able to locate a schematic. Service manual is MMGX1240S (covers GX1240/1245 models ). Thank you for any info you may provide.
Sorry I do not have any service information on any marine or aircraft radios. You need a GROL license to service them which I do not have.
i remember getting "suspect " output transistors that had the numbers either blacked out with a felt pen, or sanded off! lots of magic smoke!
I have a RK5640a running a Wilson 2000 on a 18 ft Wilson cable running for a few years w/0 SWR all the sudden it started crackling when receiving transmissions but I was able to transmit fine two days ago it just stopped receiving and transmitting all together thought cheap radio lasted longer than I expected however now I've installed two brand new radios both same issue seems when I go to calibrate it starts working normally and then the needle shoots back and forth a few times and then down to nothing no response the rx/tx lights up antenna lights off and no responses from the R/RF,SWR,CAL settings I'm puzzled could it be a bad antenna/cable killing these radios?
Yes it could. You may have a intermittent short. If the coax cable is routed through a door jamb the cable may have become crushed. Depending on what type of antenna you have I have seen loading coils fill up with water.
Wise words as usual Mike!
Mike questio for you. Does is stand true for any antenna whether vertical, random wire, etc. If Swr is 2.5 and you want 1.25 you shorten length?
Unknown, that's not enough information. The SWR curve usually looks like a spread out U or high SWR on either side of the resonant point. Measure the SWR on channel 1, 20 and 40 and take readings. Remember that as you go up in channels you are going up in frequency. Higher frequency means shorter wavelength and thereby a shorter antenna. Lower in frequency means longer wavelength and thereby a longer antenna. So if you have a lower SWR on channel 1 than on 40 shortening the antenna would shift the resonant point to the higher channel / frequency. If you have a lower SWR on channel 40 than on 1 lengthening the antenna would shift the resonant point to the lower channel / frequency.
On an FM only radio Btech GMRS-50X1 if the final is burned out, is there any other component that should be premptively replaced?
I don't have a schematic for it, own one and have never worked on one but if the final is bad that's probably all it needs. I would probably probe around with a oscilloscope first to verify it's the problem and if it is take some voltage measurements. Basic troubleshooting.
There is a project but to see the signal strength that the radio is receiving, for example, a weak but audible international station lights up 2 LEDs and one is coming in strong as if it were local, lights up 5 LEDs for a radio receiver. Do you know or have a project like this?
Had that experience. Basically, I've burned the output stage of an RF PA that I've made, due to a badly tuned antenna. Funnily, the PA is only capable of outputting 1W at best, and I was not expecting it to be damaged.
Amazing information. My question is how much did the repair for those radios cost? Would such a repair be close to the price a new radio? Thank you.
Mike, I have a dual band amateur radio I picked up second hand from another ham who said the UHF side of the radio no longer worked due to a shorted N to SO239 adapter. The radio still works fine on VHF and receives UHF fine. With an analog watt meter into a dummy load, I can see the needle just barely lift off 0 while in low power UHF, but if I key the radio on high power it blows the 15 amp inline fuse before I can see anything happen. Do you think replacing the Mitsubishi ra60h3847m1 PA module would potentially fix this radio or has more damage been done that I cannot properly diagnose or detect? I am having a hard time finding any information about testing PA modules and was hoping to find a way to test with a multi meter like you show in the video.
RF in, Gate voltage and Drain voltage all short to ground with high resistance while RF out does not short at all and the meter reads OL. Is that a sign that the finals have fail and are no longer letting RF through the PA module?
Any help or comments would be greatly appreciated.
The radio is a Connect Systems CS800D and my testing had been done on analog FM
Would this cause it to melt? Not sure mine melted it was just an old Motorola cb burnt my hand too
I’m having problems with my SWR high it goes to three no matter which way I put it on channel 1- through 40 still stays the same three I can’t get it down I checked the coax coax is fine the ground it’s fine but how can you tell if the antenna I have a trucker 2000 I’m thinking he’s got some kind of a gram problems on the van I have it on the van back of the van
Hey, I just bought a new antenna, but my radio is acting up. Can I borrow yours to check it out........
Sorry but I don't loan equipment, even to people I know.
@@mikesradiorepair haha sorry Mike. My humor's a little dry. Just trying to sum up the video in a couple words.
@@JAWS1376
LOL, it went right over my head. Now that I look at it again I get it. Sometimes things have a hard time penetrating my thick skull. :-)
@@mikesradiorepair np Mike! I know you're busy, I just want to say thanks for your detailed videos. From reading schematics to using test equipment, I've learned a lot just watching. One of these days I'll own the essential pieces of test equipment so I can maintain my collection of radios. (70's-90's) Just for alignments.
From as radio guy, just remember a SWR meter "measures" swr, it doesn't fix it. it's not a tuner (they sell tuner's separately)
I had some serious damage done to my Anytone 5555N it have 3x 13n10 but the board looks the same as yours, the TIP36S was burning hot even when not transmitting, it just happend a morning i turned on the radio while i key the mike the display got dim and the radio basicly turned of untill you released the button. It even melted the fuseholder. I saw some one talk about those 13n10 are bad, and recommend to replace them with IRF520's - anything else to replace?
I run a Francis 5.5ft whip on my truck and the SWR is 1.0 on my Lincoln II+
How I can ship a radio for some updates mod...Pls lets me know...Thanks
Very informative video, Thank you!
Thanks for showing!
Mike, thank you for the videos, they're so helpful. Just curious, can you test the AM regulators and the drivers the same way you tested the finals? I'm trying to find out why a Cobra 25 LTD Classic won't transmit or receive. (I already checked the cb/pa switch and caps esr.) The sound chip makes noise when I put my finger on it. The signal meter isn't moving, but it's not "stuck", it moves freely - doesn't move when receiving signal is being broadcast. In the rear of the 25 there are two transistors. The one near L12 is the final, but what is the one in the very rear corner and what is the one by the volume/on/off switch? Thanks!!
When you say does not transmit, you mean you have a dead key but no audio ?? The audio chip on the side of the chassis might be your issue. The 29 and the 25 radios DO require those 2 thick rubber washers between the mount bracket and the case of the radio.... If their not in there then when you tighten the 2 knobs they pull the case away from the PCB slightly and the solder joints fail.... Example no receive in the speaker and no audio going out....I have seen that a few thousand times....
@@cajuncoinhunter Thank you for writing back. If you watch this video someone posted, this is exactly what happens with my Cobra 25 LTD...it's easier to watch his video than me trying to explain it, but everything that happens in his video is what happens with my 25 LTD...here's the link for you: ua-cam.com/video/nzqjIKUKBsg/v-deo.html
Do you figure it is exceeding the max voltage or the max current or both that blows those finals when SWR / RL is bad?
Great info. ✌✌
so there was no swr protection in these radios?
Mike, are there different SWR meters for different bands, or are they all the same? I have one that I used for my CB, will that work with my Marine VHF?
No, they are not the same. You would need to look at the specification sheet for the meter you have but most meters used on the amateur radio HF bands and on CB only cover up to 30MHz and maybe a little higher.
@@mikesradiorepair Thank you!
Just a reminder to those who make their own coax cables:
Coax, (especially the foam core), can suck in water like a fish. It's amazing how much water can wick into your cable if it's not properly sealed. You can generally tell this is happening if your SWR is good on a dry day and they goes wonky after it rains. Then it dries out and your SWR is good again. Chances are you have water in the line or your antenna itself has some water intrusion somewhere.
So make sure your antenna system is SEALED. The coax is overlooked and skimped on 99.9% of the time. Waterproof all connectors. You can use Mastic tape on connections you may want to remove later. Just make sure and SEAL it. Also routing your cable out of the direct weather is a good idea (under your house eave, car hoods, etc). Little exposure as possible.
For underground runs, I put mine inside electrical-grade conduit for extra protection. A little extra work and expense, but It's cheap insurance. It also helps if you find yourself digging later around your coax. You'll hit the conduit first and not damage your coax.
I also like to use heat shrink (the type with the glue inside) to seal where the coax enters the connector. I don't rely on the solder alone for sealing. Get GOOD GRADE heat shrink. Not that cheap Rat-Shack, Harbor Freight thin garbage. Get the 2 or 3:1 stuff with the heavy glue. This stuff will seal just about anything. Likewise it's tough to remove so be sure your solder and coax tests out OK before you install the shrink.
I remember years ago, operators stating that their match would improve in the rain. I never tried to disprove or prove that because I never gave it much thought. Recently I have learned the importance of sealing the coax and the connection that faces the weather on a daily and nightly basis.
Very good post... Very well said. Listen to this guy; he knows his stuff...
Self amalgamating tape is is good also, especially if you live in a area with destructive birds that like chewing on coax ends. Though usually they are that particular, gotta chew it all in some parts of the world.
SWR stands for Standing Wave Ratio...how do you get SWR's? People do the same thing with RPM...pet peeve of mine I guess...
bit like when people say 73's...
Because he's a CBer.
Christ almighty...
All about the reflection
@James Marquis Don't try pushing your bullshit on me.
How important is your coax for lowering swrs I'm having a lot of trouble
Ideally your coax cable shouldn't effect your SWR. It's a 50 ohm transmission line. However if your coax cable has poorly installed connectors, has had water intrusion into the jacket or has become kinked or smashed that can greatly effect the impedance of the coax cable which in turn would manifest as a higher SWR. The big difference between grades and the diameter of the cable is the loss. Larger diameter and higher grade coax cables have less loss meaning more of your TX power actually makes it to the antenna and on RX more of that signal makes it to the receiver in your radio. The big advantage of working in the HF range of frequencies is you don't need to get crazy with extremely large diameter coax. Loss doesn't become a big factor until you get into the UHF range or higher. Personally most of my HF antennas with runs under 100 feet I use LMR240, over 100 feet I use LMR400. At UHF frequencies I use LMR 400 for shorter runs and LMR-600 or 7/8" hardline for longer runs. My microwave antennas have at a minimum 7/8" hard line with most being fed with 1 5/8" hard line.
I've got a cobra lt 29 and I have one switch is bad how hard is it to change or fix
I have a galaxy 33hml and I checked from the ground on the transistor to the opposite side and had continuity between them on both and it didn’t matter which lead I used on the ground but there was no continuity from ground to the middle of the transistor. Does that sound burnt to you?
please tell me you could still fix my radio!
I love your videos. I learn a lot about radio from watching your content, thank you. Question - if the finals get blown so frequently, and pass on current for more internal damage... shouldn’t they build in a fuse?
Read the support boards for the ubitx theres a nice protection mod using a P-FET like the IRF9540 as finals draw power from the 12volt input
Hello there,
Yesterday we had a snow storm and i heard a (tik tik) poping sound coming from my coax . I was not transmitting with the radio. this morning i turn the radio on it receive ok but when i puch the PTT, no modulation indicator an all mods. what could be the source of that poping sound and could my radio be fixed. any idea ?
Same radio President Lincoln II
thanks
That doesn't sound good. Lightning storms, snow storms and sand storms can all cause ESD damage. Every snow flake that hits a antenna can deposit a small static charge and that charge builds up. Eventually the potential gets large enough it can arc over and unfortunately it sounds like it arced over inside your radio. It's hard to take a guess as to what got damaged. You would need to trace out the PTT switching circuit.
@@mikesradiorepair ok mmmm too bad your so far away (lol) Thanks for your reply and I love your videos .
have a gr8 day 73s
Hi mike,
I set up a 148gtl and my swr on the radio is high!. I put a mjf antenna tuner between the radio and the antenna. The meter on the tuner is down to 1.1 but still high on the radio. Should I disregard the reading on the radio?.
Thanks in advance,
Ernie.
Do you still work on radios?
I am searching for HELP! I recently purchased a 10,11,12 meter President Lincoln II + I can not get SWRs lowered no matter what I do?????
Good video ☺️
Hey Mike Bruce from Columbus can you get or is there available a frequency display for a ranger RCI 2960 FJP one leg is starting to flicker???
If I want to send my cb in for repair where would I send it to for you to work on it?
Excellent video! I have about four old radios laying around I think this will fix! Thank you so much, and I just subscribed.
I have a Cobra 29 soundtracker in my truck and I recently put speakers headlamps in my truck and now my RF reflection is really high how do I get it back down
My cb gets power but doesn’t transmit or receive. Guessin I blew out a resistor in it. Cobra 29ltd. 4 years old.
In you professional opinion. I have an old Cobra 40 channel cb, LTD I think it was, that I used for 20 + years trucking. I spent over 35 years OTR & this was my 3rd radio. It has been boxed away for a dozen years or so. Are these worth going through, checking out & repairing if need be or is it better to buy something new. Just want to put it in my pickup just to have when I am on the road with my horses. Also I live on top of a mountain so I would like to see if it is like it was years ago where you hit the skip & could talk a long ways off. Just something to have some fun with. Also thought about hooking a linear to it. What's a good antenna these days? I always liked the K40's but didn't know if anything else is better. If I do what I am thinking of it will be mounted in a Dodge pickup.
Thanks for your time.
Mike can you tell me can you tell me if the a.m. regulator would have anything to do with me mod fading out on the FM frequency after about 20 seconds it goes right back signal stays good but the mods fades out on the FM band I am in the UK and the radio is a Stryker sr955.thinks
Great job as always Mike. Just curious if those finals were good what would the foward and reverse resistance be?
Thank you for sharing your info on radio repair!
That's exactly what I was looking for in the comment section...what the reading would be had the finals not blown? Please let us know! Thanks again Mike for sharing your knowledge with us! Brian
if theres a short in the finals can I put some current across that until its open and theyll be good again lol? Good video though. de ki4hou
My antenna must have gone south and when I keyed up my Telsat 140 I lost receive and transmit. What should I look for ? Finals blown??
Is a 1.5 swr on highpower on an anytone 6666 bad?
It's not horrible if that's what your asking. With a SWR of 1.5 you are transmitting 96% of your power and 4% is being reflected back to the radio. Start to get worried when you get near 2.0 to 1 SWR. With a SWR of 2 you are transmitting 88.9% of your power and 11.1% is being reflected back to the radio. At those levels and above you start to risk damaging the output section of the radio.
MikesRadioRepair my swr usually is at 1.5 dead key at like 50 watts and then jumps up to around like 1.6ish when modulated is that bad 😬 and thx for the reply
Come back to you tube,Mike . I need some radio work done…
will this work on a uniden 510xl and the 520 xl
Does anyone know what happened to Mike?
😢
What's it mean when I key my mic the needle doesn't move?
I have a radioddity qb25 do I need to tune my antenna
Mike, Good video...If the final has been replaced in a cobra 29 Ltd classic and still doesn't work, and let's say the regulator is also blown. What will the symptoms be for such a problem. Would the radio fail to key up ? By the way the driver has also been replaced along with the audio chip. Thanks, Billy
I'm trying to set up a really old set , Midland . 50ohms impedence ? Hmm , I've heard that be fore . Impedence is resistance . But you still need a opposite polarity reflecter for antanna to work ( I think) . Just don't short it . Broken coax . Splices will cause problems too .
Now, if I could make heads or tails of my switching power supply layout vs. schematics to fix it. It blew out the mosfets... strange because it is supposed to have overheat, over current, over voltage protection, but when doing testing using it, it overheated and did puff the magic dragon on me.
I have replaced those, but the supply is stuck in protection mode, and I'm at an impasse.
Alinco DM330MVT
Switch modes are like Morris the Cat, finiky ;) I've seen the coils change value and thus change the frequency and blow the mosfets!!!
I had a lighting strike one of the antennas that I had up. I had my ham radio unhooked. but I had a free play radio and a am drake which both got hit by the lighting. magic smoke came out of the drake. still got it around here some where. after it killed those two radios. it by passed the big screen i had bought was fine but it went on past and fried the misses computer. go figure.
Thank you.
Hi I need to know if you repair mark 3 browning
I wish you'd come back
Hi Mike, really enjoyed that video. I have the same radio and it's the first time I've seen what it looks like inside. Mine get's so hot where that regulator is, the case is almost too hot to touch if I run the rig above 5 watts - the finals heat sync never gets warm so I suppose that's a good thing? Is the heat normal for these radio's?