[Milsurplus] BC-611 troubleshooting questions

[Mike Feher]

It has been at least 25 years since I seriously played with 611s. The two
major issues I found were leakage in the plate to grid coupling caps as well
as others, and corroded leads inside the IF transformers. Replacing
capacitors is easy, fixing IFs not so much, but both can be done. With such
high value resistors in the circuits in order to maximize battery life, even
a couple of meg-ohms of leakage in one of the coupling caps can drive the
grid positive, causing degraded audio, distortion, and if bad enough, tube
cutoff. Bypass caps can pull down the B+ or affect AGC. When you measure
voltages use a very high impedance volt meter, or else the meter itself will
affect the readings. Anyway, those have been my experiences to the best of
my recollection. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 


-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Jack Antonio
Sent: Monday, April 14, 2014 3:17 PM
To: milsurplus
Subject: [Milsurplus] BC-611 troubleshooting questions

Finally getting around to working on my BC-611, and would like to ask a few
questions. Hopefully I can make this play for Dayton this year.

It is an -F model, and came with 3885 crystals installed, and the right
antenna coil, so I am assuming that it was tuned up and working at one time.

And no, I do not have any of the IE-17 pieces.

1.  Are there any known high failure parts, that should be replaced as a
matter of course?

2.  How well will the radio work, outside of the case?
I know that it will be detuned, but will it work well enough to establish
that it is working at a basic level?

3. Again, assuming that it was tuned up and working at one time, and that no
one has diddled with anything, how much do the tuning adjustments drift over
time?

So far, I've given it a visual inspection, and using the point of a
toothpick dipped in De-Oxit, have cleaned up the multi-section slide switch,
and verified with an ohmmeter that switching action is as it should be.

Next step will be resistance and voltage measurements.

Thanks in advance

Jack Antonio WA7DIA/4
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