Great repair Peter. The SMPS is a weal link in these old rigs. Funny when you mentioned how old they were, I remembered when they came out. Wanted one bad then. Thanks Peter.
Another important point to check with that particular type of SRBP pcb, is whether any black/ charred areas have become conductive. I have been caught out a few times by low resistances due to burned/carbonized board bridging overheated power resistors.
give some credit to the designers of that PSU. It worked problem free for 30 years. All you had to do is to change a few capacitors, and it will work for another 20 years. 105 degrees capacitors are a bit weak for this unit, you can already find 135 degrees ones at all major distribuitors in Europe. They are not that expensive either.
Any quick tips if it still doesn't power on when you plug it in to external 13.8v power supply ? I've seen some do this, just curious what else might be causing it to be dead on external supply?
Hello mate, do you have a video where you test caps with the required input voltage or possibly a lower voltage for testing purposes and monitor the waveform on a scope to determine if the cap is good or not based on charge time? Love your videos as I am an electronics wanna-be, LOL. I love hands-on component replacement.
Hi Peter, our radio club has a 736R that suffered from the same power supply issues, got that fixed OK, now our 1.2 GHz module has become "sick".... Typical. Many thanks for the apt video!! 73 as always, Brian EI8EJB
A very common fault with old SMPS's. Well diagnosed and fixed as usual. Also a great lesson on how to test capacitors too, just measuring the value is never enough to decide whether they are good or bad. In fact most of the time bad electrolytic caps will show higher than their rated capacity because of the way most multimeters calculate their values based on charge time. That darkened part of the PCB got me worried though, it requires a substantial amount of heat to burn a PCB like that, how do you think that happened?
Great video thank you. This is inspiring, I have a mini fridge with a power supply problem so I'll be analyzing the circuit to see what's up. Cheers. (I wish I had all of your test equipment!)
Great job Peter. The first thing I do when I suspect capacitor problems on older printed circuit boards is to immediately replaced all the electrolytic capacitors.
I've had to repair a few silly faults on one of those. There are wires and connectors everywhere! Thank God for camera phones. The memory battery and VFO are notorious for needing TLC I think you already did a VFO rotary controller video. Another old radio saved from E-waste... 👍👍👍
This makes me think I should open up my Icom HF radio from the 1990s and just check a few caps etc... It is getting to that age. Still works fine but worth a check.
Thank you Peter for the video, it came just in time for me relaxing in the sun looking your always very good explanation of how and why. I like that cms50, i still searching for the latest 6.x firmware.
I repaired one of these in 2018 for a local hospital. In full disclosure, I simply replaced all of the electrolytic caps on the SMPS board and it came back to life.
I don´t want to be bossy, but one remark: Repair or maintenance: Keeping equipment operational, not necessarily with original components. Restoration: Restoring to its original(!) state. (See Wikipedia). Old equipment in general can´t be restored due to lack of original components; it can "only" be repaired, e.g. by replacing old components by new ones, which are different (sometimes better) from the original ones; for example old transistor by a new/modern one with the same function and parameters. So what you did here is a repair - nice video!
lol Yeah Stefan following the wording of the definition your are right but it is a little bit like the discussion about Schreibendreher oder Schreibenzieher oder Röhresockel oder Röhrenfassung......everyone knows what is meant and so I'm certain it is here...The thing is that a radio older than 25 years can't be called a normal repair as it is blocking the bench (factor time) while other OM's waiting for a fix. On the other hand due to logistic and research it becomes much to expensive (factor costs) and 3rd factor rabbit hole means warranty. A complete other discussion is the fact that I don't agree with the definition written down in Wikipedia. It does not cover all the variants which can't be ignored. But as I said a different discussion. But to be clear your comment is highly welcome and is always worth a debate... 73
Peter, I'm so glad your back. Your videos are very informative, and entertaining. Please keep them coming.
Danke Peter! Love your videos! Please keep it up!
Great repair Peter. The SMPS is a weal link in these old rigs. Funny when you mentioned how old they were, I remembered when they came out. Wanted one bad then. Thanks Peter.
Hi my friend, yeah it is shocking realising how quick the time passes by..Stay safe and healthy!
Another option if the supply were truly dead would be to simply replace it with a modern SMPS module in the same space. Nice fix Peter! 73 - Dino KLØS
Thanks Dino and yes today we have a variety of SMPS on the market which will simply fix those problems.. 73
I really enjoy the enthusiastic introductions in your recent videos, Peter! Great content as usual, too. :-)
Another important point to check with that particular type of SRBP pcb, is whether any black/ charred areas have become conductive. I have been caught out a few times by low resistances due to burned/carbonized board bridging overheated power resistors.
You are right very important point but in our case it was not already carbonised so we were able to ignore it.
give some credit to the designers of that PSU. It worked problem free for 30 years. All you had to do is to change a few capacitors, and it will work for another 20 years. 105 degrees capacitors are a bit weak for this unit, you can already find 135 degrees ones at all major distribuitors in Europe. They are not that expensive either.
Any quick tips if it still doesn't power on when you plug it in to external 13.8v power supply ?
I've seen some do this, just curious what else might be causing it to be dead on external supply?
Thanks for the video,I have the 736r for satellite work so now I can fix the psu if it fails! Gm4zji Chris
Hello mate, do you have a video where you test caps with the required input voltage or possibly a lower voltage for testing purposes and monitor the waveform on a scope to determine if the cap is good or not based on charge time? Love your videos as I am an electronics wanna-be, LOL. I love hands-on component replacement.
why bother to repair old smps?? you could put a new smps in same dimensions ;) even its been repaired i would never trust that PS again :/
Super enjoyable. Thanks for a great Saturday morning video to start the day. It is much appreciated. I always enjoy your projects.
First things first if the fuses are alright then should we check the PSU board as the fault must be there.
Thanks for the repair. I like the capacitor facts.
Hi Peter, our radio club has a 736R that suffered from the same power supply issues, got that fixed OK, now our 1.2 GHz module has become "sick".... Typical. Many thanks for the apt video!! 73 as always, Brian EI8EJB
Yeah all those rabbit holes with this old units :-)
Great job as usually Peter, capacitors are often the problem :-) 73s, stay safe, Pasquale IW0HEX
Thanks Pasquale , Stay safe too
You have a new sub. Regards.
Dont stop dont stop !! This need to be saved forever as historical files.
Okay but why historical??
@@TRXLab watch the movie = galaxy quest !!
What about using the best Japanese electrolytics that you can get and see if that solves the problem.
sure and that is what if have done
Thanks Peter 👍🇬🇧
Peter. informative video as always; always good to see you.
Thanks Bob
A very common fault with old SMPS's. Well diagnosed and fixed as usual. Also a great lesson on how to test capacitors too, just measuring the value is never enough to decide whether they are good or bad. In fact most of the time bad electrolytic caps will show higher than their rated capacity because of the way most multimeters calculate their values based on charge time. That darkened part of the PCB got me worried though, it requires a substantial amount of heat to burn a PCB like that, how do you think that happened?
Great video thank you. This is inspiring, I have a mini fridge with a power supply problem so I'll be analyzing the circuit to see what's up. Cheers. (I wish I had all of your test equipment!)
When they blow i like to say they are into Smoke mode power supply.
lol
Very good video and analysis peter as always. Very informative one. Weekends are better with some of your videos available. Thx for your time
Great job Peter. The first thing I do when I suspect capacitor problems on older printed circuit boards is to immediately replaced all the electrolytic capacitors.
I think that meter was set to measure resistance, not ESR. 18:00
No resistor is on this meter DCR
thank you Peter
Very interesting. You make it look easy Peter. Your experience really shows. Thanks.
Nicely done Peter as usual!!! 73 from Jeff de WD8JM
Very good video.
Yes that's a great radio, we have one at the club station and now I know what to do if it stops working. Thanks as always another great video!
Great old radio in perfect condition!
I wonder why you decided to replace those yellow capacitors and which brand are new?
Welcome Back peter great informative video as usual keep them coming
Nice easy repair this time Peter. Nice video on repairing the power supply.
thank you
What frequency do you set the meter to when doing ESR measurements?
100khz
@@TRXLab Super, thanks!
My beats faster when you post an SMPS repair videos.
lol made for you
@@TRXLab lol
good job and nice video guy..very good information
I'm happy to see you AGAIN.
Your project balun 9 :1 for my longwire antenna 16.2mt lenght, works very very well. Thanks. Enzo IT9UMH 🇮🇹
Thanks Enzo glad that you are satisfied with the balun..
I've had to repair a few silly faults on one of those. There are wires and connectors everywhere! Thank God for camera phones. The memory battery and VFO are notorious for needing TLC I think you already did a VFO rotary controller video.
Another old radio saved from E-waste... 👍👍👍
yes agreed a nightmare..
Glad to have you back Peter always enjoy your videos hello from Texas Hill country.
WD5ENH
Steve
best wishes and 73 over to Texas!
Great to see you again, I always love your videos and love the Lab. Wish I knew of a great RF Engineer/ Tech near me in Southern California . DE K6PA
Do I have to move to California ?? Oh no it's not me I'm an average Engineer lol
This makes me think I should open up my Icom HF radio from the 1990s and just check a few caps etc... It is getting to that age. Still works fine but worth a check.
alwys good to check..
Nice repair. Thanks for the video Peter.
Thank you Peter for the video, it came just in time for me relaxing in the sun looking your always very good explanation of how and why.
I like that cms50, i still searching for the latest 6.x firmware.
Thank you Michael!
Hi Peter. Thanks for another great video.
Another success for Peter, the super sleuth!👍☘️
12:11 they must be flux capacitors. :)
So many great instruments you have there. Must be a joy repairing anything.
73.
lol yeah...Well you nee stuff to efficiently fix devices. It is always a question of time...
I repaired one of these in 2018 for a local hospital. In full disclosure, I simply replaced all of the electrolytic caps on the SMPS board and it came back to life.
yeah that is often the case..
Good video..but seems you need to fix the s-meter backlight also, am i right ? '73 have a nice weekend .
LOL yes we always can do what we have a work order for :-)
Nice repair and good explanations of why the caps were the problem...... thanks
thank you
great job!
Thank you
just saying...hehe
Okay why hehe??
Thanks again Peter.
I don´t want to be bossy, but one remark:
Repair or maintenance: Keeping equipment operational, not necessarily with original components.
Restoration: Restoring to its original(!) state. (See Wikipedia).
Old equipment in general can´t be restored due to lack of original components; it can "only" be repaired, e.g. by replacing old components by new ones, which are different (sometimes better) from the original ones; for example old transistor by a new/modern one with the same function and parameters.
So what you did here is a repair - nice video!
lol Yeah Stefan following the wording of the definition your are right but it is a little bit like the discussion about Schreibendreher oder Schreibenzieher oder Röhresockel oder Röhrenfassung......everyone knows what is meant and so I'm certain it is here...The thing is that a radio older than 25 years can't be called a normal repair as it is blocking the bench (factor time) while other OM's waiting for a fix. On the other hand due to logistic and research it becomes much to expensive (factor costs) and 3rd factor rabbit hole means warranty.
A complete other discussion is the fact that I don't agree with the definition written down in Wikipedia. It does not cover all the variants which can't be ignored. But as I said a different discussion.
But to be clear your comment is highly welcome and is always worth a debate... 73
@@TRXLab Yes, Peter. I see, we understand us.