Kenwood TS-520 Screen Rectifier Board

Rebuilding the TS-520 screen supply board

We all know electrolytic capacitors age with time. Their dielectric dries out and they begin act like resistors, passing increasing amounts of AC current until one day when you flip on the rig—BooM!—you’re done.

Avoiding this day is the purpose of preventative maintenance, particularly the recapping of old electrolytic capacitors found in the power supplies of old equipment. This should be at the top of your list whether you just arrived home with a Kenwood hybrid from a hamfest, or find your finger hesitating over the POWER switch of a rig just brought up from the basement.

BEFORE…

In the TS-520 I have been using for over 40 years, I’ve replaced the filter caps twice so far. The last time I went to do the job, I looked at the foils on the stock rectifier board and decided to replace the board with a piece of perfboard populated with modern components.