[R-390] It _WORKS_!

[mikea]

Last night I finally had the time, inclination, clear workspace, and
tools to try to get my R-390 (Collins, great restoration by Mish) up
again. It had Just Stopped Working a few months back, and things were
not conducive to my getting into it until now.

Symptoms:	No audio out, no carrier level meter deflection on 
			any band, even with a signal generator as input. 

So I got the -20 and -35 manuals out, heated up the scope and 8640B,
opened the critter up, and ran through the problem determination
checklist:

o	no response to any signal on the antenna connector;
o	good response to 455 KHz modulated with 1 KHz on the 
	IF strip input jacks;
o	OK response to RF on the test point at the output end of the
	RF module, but not at the other end. 

Conclusion: Probably something in the RF module.

Found the tube extenders (a battle all in itself, after I cleaned up
the garage), pulled the middle tube, put it on the extender, and ...
the radio worked! Left _EVERYTHING_ else just as it had been, replaced
the tube, and it _still_ worked.

I spent the rest of the evening cruising around, listening to hams,   
refining my SSB tuning technique, and having a good time.           

It probably was oxidation on one or more of the socket contacts and/
or the tube pins. That's my story, anyway, until it quits again. It's
easier to shoot a solid bug than an intermittent one.

-- 
Mike Andrews
mikea at mikea.ath.cx
Tired old sysadmin