Quick update on the SB-220:
After getting the HV supply working, I was still having trouble getting RF
out. The relay wouldn't key
via the TS-590S, and when I tried to key it by directly shorting the inputs, it
would sometimes key and
sometimes not. And when it did key, it didn't click very loudly and seemed
I figured something was wrong either with the relay or the relay keying
circuit. The keying circuit was easier
to fix, so I replaced the Harbach soft-key board with a new one. I also ran a
piece of paper between the relay
contact to clean them a bit. Now I get a solid *THUNK* when the relay keys, the
TS-590S switches it just fine,
and it puts out between 1000 and 1500 watts out depending on band. It works!
Now my primary question:
Even when running a 20 minute SSB QSO yesterday at a kilowatt on the low
voltage CW setting, the 3-500Z's
didn't appear to be cherry red. (The inner case is closed, so they are not
easy to see through the holes; the
outer case has not been put on yet.)
I am a bit concerned that they aren't hot enough to getter even though they
are putting good power out. I don't
know how long the amp was unused before I bought it. Any thoughts on ways to
get them a bit hotter?
Perhaps run some RTTY at 400 watts for a while?
I am not seeing any purple glow, arcing in the tubes, or other signs of
failure. And the power levels I'm getting
(1400 watts on 40, 1500 watts on 80, both with 100 watts drive and SSB voltage
setting) suggest that the tubes
are not at all soft.
Hope everyone had a wonderful Thanksgiving, and that the bands improve soon!
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