The power supply testing is done

Defective part 
The power supply troubleshooting is all done and tomorrow I will order the replacement parts, but first, there were two things I mentioned in the last post I wanted to correct........

1. I am recently retired and I was told you would slowly forget what day of the week it was, well that has not happened as of yet. I can say that with regards to ham radio contesting this retiree has mixed up what contest was on what weekend! In my last post, I had the idea of the CQWW CW contest was on this past weekend and in fact, thanks to my fellow bloggers I was informed it is next weekend. When I went back to the ham radio contest calendar site it sure was plain as day that in fact, it is next weekend. This is a good thing because my new Astron power supply will be here and I will be good to go for the contest.

2. In my last post, I indicated the varistor was defective and posted a picture of my Fluke meter indicating OL. DUH.....this is an indication the component is just fine!
Pass transistor testing 

Now the power supply troubleshooting is done and I have to thankfully replace only one component and again the failure of the power supply is my own fault. The power supply is an Astron RS 20M and it is rated at 16 amps continuous, this has been just fine when I was operating QRP at my previous  QTH. As my readers know I am now retired and have moved to New Brunswick and my new antenna is an Endfed. I have been raising the power output of the 7610 slowly and slowly but forgetting I am only using the RS 20M power supply!! The result was a failed power supply as it was just not rated for what I was attempting to do.  The new Astron power supply has a 25 amp continuous rating and the Icom 7610 is rated at 23 amps continuous so I will be good to go.

Back to the final power supply troubleshooting, I checked the 2 pass transistors and they both passed. I then checked the balancing resistors connected to the emitter of each pass transistor and they were both good. There were some capacitors that I also checked and they too passed. It seems that the only component I need is a bridge rectifier along with a tube of dielectric paste for the pass transistors and a new bridge rectifier. I am very happy the repairs are minor to the power supply.
Positive test results 

Mike Weir, VE9KK, is a regular contributor to and writes from New Brunswick, Canada. Contact him at [email protected].

6 Responses to “The power supply testing is done”

  • Colin GM4JPZ:

    Thanks for posting your failures as well as your successes, Mike. It really helps to see that others can forget basic facts and blow power supplies as well! I made a similar mistake years ago and never forgave myself, now I don’t feel so bad.
    73, Colin

  • Lenny Wintfeld:

    Astron has a reputation for being optimistic with their specs. When I got my RS20M I put a fan on the heatsink right away (run it off the Astron output). It’s been working fine for years with loads of 16-20 A (and occasional, and inadvertent brief excursions to 23A). I’m sure the fan is helping it survive — cheap insurance.

    Good luck with your repair!

  • Clint, VE3CMQ:

    Hey Mike. I am glad you have it all figured out. I am having a similar type of problem here, being retired and all. I have been working on an old transmitter for a few years as I had a move from Alberta to Ontario in 2017, got a job, worked too much and still don’t have my shack operational! By the time I got back to it, I had to relearn what I had done. I forgot a lot and keep letting the smoke out of Mosfets that I have been using as control devices in an old Ranger. Today I seem to have blown a 6146 do to a screen problem.

    Anyhow, you aren’t alone! We are all here to help each other.

    73, Clint, VE3CMQ

  • Mike VE9KK:

    Good evening Colin very nice to hear you, yes I have had a few of those moments in my life time. This has given me the chance to trouble shoot the power supply. The parts were order today and I hope it will be operational by the weekend.
    Have a good week Colin

  • Mike VE9KK:

    Good evening Lenny, I had a pyramid power supply that I did the same with as it was running hot.
    Have a good rest of the week

  • Mike VE9KK:

    Nice to hear from you again Clint, it sure sounds like you have your hands full with trouble shooting. I ordered the parts today from Digikey and they should arrive this week sometime.
    Thanks for the reply

Leave a Comment

Subscribe FREE to's
Amateur Radio Newsletter
News, Opinion, Giveaways & More!

Join over 7,000 subscribers!
We never share your e-mail address.

Also available via RSS feed, Twitter, and Facebook.

Subscribe FREE to's
Amateur Radio Newsletter

We never share your e-mail address.

Do you like to write?
Interesting project to share?
Helpful tips and ideas for other hams?

Submit an article and we will review it for publication on!

Have a ham radio product or service?
Consider advertising on our site.

Are you a reporter covering ham radio?
Find ham radio experts for your story.

How to Set Up a Ham Radio Blog
Get started in less than 15 minutes!

  • Matt W1MST, Managing Editor

Sign up for our free
Amateur Radio Newsletter

Enter your e-mail address: