Monday, November 18, 2019

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 


  1. Hello Mike, well I missed your post from yesterday since I'm a bit ill. But the first thing that came to my mind was that the RS20 is a bit tiny for your IC-7610. Luckily you discovered that as well. Sometimes we have to discover the hard way. You didn't miss anything since the CQWW is upcoming weekend so you will have fun.... I own a Astron RS50A, bought 2nd hand. It is rated 50A peak and 37A continue. I still like supplies with a big transformer although I do have a 25A switch power supply as spare. 73, Bas

  2. Good evening Bas yes, it sure was a learning experience, but I was able to troubleshoot the power supply. I ordered the parts today needed to repair the supply. The supply I have coming is an Astron 30 amp switching supply rated at 25 amps continuous. I was looking at the liner Astron supplies, but they were just too pricey for the budget I am on now. I did check Eham and this supply (SS30M) had very good reviews. There was some negative feedback regarding the type of DC terminals they are using. This is not a big deal to me as if I want I can change them. The comparable linear supply with shipping was about 130.00 more.
    Thanks for the comment Bas and have a good week.