TS-520s Fix Update

Received a used replacement USB carrier crystal from Mr. Walter Dilley, KD7DNY.  Many thanks to Walter, who continues to supply old hybrid parts (like this TS520) to the ham community.

Walter advised that I check the solder connections on the crystal, because he observed bad solder wetting on several other modules.  I took a look on Terry’s unit, but it was soldered properly.

I did a quick remove and replace of the 3.3965 MHz crystal.  Hooked up my frequency counter to the Car Unit X50-0009-01 ouput lug and fired up the rig.  Made minor adjustment on the TC2 trimmer cap to make the frequency spot on for USB.

Took my trusty can of freon and sprayed the crystal as done previously.  Joy!

The crystal withstood a fair frost and it’s frequency only driven a few tenths of  KHz.

Stable and strong compared to the previous one.

Buttoned up the rig (found a missing chassis screw, and cannibalized the one from a carcass TS940 in the shack), and test out A-OK!
Terry asked me to check the power.  Used my in-line Bird and observed ~80W out on 14/7 MHz and ~40W on 28 MHz.  The lower emission on 10m is a common phenomenon but it could reflect the softening of the 6146 finals and/or the 12BY7A driver (also a common condition).

Another great boat anchor back on-the-air.




1 thought on “TS-520s Fix Update”

  1. I cant thank you enough, I stumbled across this working on a ts520 my grandfather gave to me. Usb went quiet and ive been pecking at it for 3ish years now, buying test gear and trying to understand what makes this thing tick. I refused to ship it to someone I dont know and have a 200lb gorilla playing in my immaculate radio. Ive contacted Mr. Walter ive got my fingers crossed that he has a spare crystal and I can get this thing back on the air!


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