[Hallicrafters] SR-400A - no output - solved

[Don]

I've made two previous postings about "no output" on my SR-400A
plus others about the SR-400A's fan and CW operation.

I'm happy to announce that the SR-400A is now operational.

I'd like to again thank all those who replied to my postings.

I'd like to extend a special thanks to Walt, WD0GOF, who took the
time to exchange numerous emails and provide much advice.

The cause of the "no output" is interesting. C212 was a small silver
mica capacitor that measured less than a few pF instead of the correct
0.02 uF ceramic, and, a 10 pF capacitor was installed in series with
C15. The result was that the 2nd xmtr mixer and the xmtr driver would
only tune properly on 20 metres and, thus, the rig would only transmit
on that band.

The interesting part is that both these "modifications" appear to be
original. They were the same vintage parts as the others, had the same
grunge on them, and there is no evidence of the parts having been replaced.

It seems that this radio may have never worked properly or, perhaps,
that it was deliberately manufactured as a single band radio!

73, Don  VE3HUR