I have several SB-220's which I have worked on over the years to keep
going. I'm not an amp expert, but have fixed several. Most of the
time, the problem is in the HV power supply. This time it's not, the
meter shows about 3,200 V, so I have HV, and the tubes are lit. The
problem is there is no power (0 watts) out, with 100 watts drive on
all bands. There is continuity between the HV power supply and the
plates of the tubes. Also, the relay appears to be working, ie. they
click when energized, and a continuity check from the input to the
grid caps look good when keyed by hand. One other thing, this amp
failure was without sparks/ smoke/ fire as my other enlightening
experiences have been. Any ideas or suggestions appreciated.
73 Denis W4DC (x-WD4KXB)
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