Hi Irv,

I would have to look at the contacts to be able to make a
true prognosis, but typically if the contacts aren't snagging
the paper (eg, not badly pitted), you can clean them indefinitely.

I would modify Tom's cleaning regimen to use typing paper dipped
in 91% isopropyl alcohol. The alcohol will remove any oils or greases
that might, for what ever reason, be on the contacts.

If the contacts are pitted, then you need to do some more work. Take
an old hacksaw blade, and grind off the teeth, and make the width a
little wider than the contact. Then very lightly grind the flat faces
of the blade to thin it down, and to make fine scratches perpendicular
to the blade's length. Kind of like a very fine file. Don't even think
about using a file, or any kind of sandpaper!

Use this new burnishing tool to polish down the pits. Keep the contact
crowned in shape. When you are done, use compressed air to clean the
metal flake out of the relay, and then clean the contacts with isopropyl
alcohol. You don't want any oil on the contacts.

After you do this, the contacts should be good to go for another 5-10
years.

-Chuck Harris


Irv Finkleman wrote:

I did that Tom, but thanks for the tip. I consider the TS-820, 830, and
520 series to be some of the best rigs ever built. My assessment is based
on my experience as a navy tech for 26 years, and then Sony tech for
an additional 14. The only regular problem I've encountered in these
units has been that darned relay. In every case I've cleaned the relay
and restored operation. I currently run a TS-520S and figure I can keep
it alive as long as I live. I'm not sure just how many times you can
clean a given relay, and wouldn't mind having a spare on hand. I have
encountered other problems, usually just a faulty driver or final tube,
and then usually a result of overdriving -- but those are easy fixes.
What I do like are the circuit boards -- well made and easy to repair if
required. The only circuit board repair I ever had to do on a Kenwood
was a blown regulator which was the result of someone sticking a
screwdriver into the rig and shorting a line!

Enough rambling....

Irv