H. P. Friedrichs wrote:
I recently acquired a BC-348 Q in fairly decent shape and have set about
getting it into useable condition.

First, I found a dead tube (open filament). Since some of the others
tested weak on my tester, I collected a full complement of NOS tubes
and repopulated the set. No go.

Next, I found a wiring error made by somebody who had attempted the 28v
to 6 volt filament conversion. The error left both sides of one of the
tube's filaments hooked to A+, i.e. no way it could light up. This was
easily corrected.

Once I fixed this, I could hear stations...albeit faintly. While poking
around the 1st RF section, I found an open (literally cracked open)
plate resistor. With that replaced, the radio generates enough volume to
drive a small speaker to comfortable levels.

I cannot seem to get the BFO working, however. The resistors around the
BFO seem to check out ok. The condition of the caps are unknown at this
time, though I have not run across bad silver micas or the pF dogbones.

I know the larger uF caps are prone to dry out and deteriorate, but I
tried shunting a few of them with alligator leads and known-good units.
It didn't seem to make much difference.

What are my options? Is there a common failure mode for the BFO in this
set? Short of removing parts and testing them out-of-circuit what are my
options? Does anyone have a functional BC-348 Q who could give me
nominal voltage readings around the pins of the VT-233 that I could
compare with mine?

I would like to help. I have a 348Q in quite good working shape, but I
would not be able to get into it to take measurments for about 10 days
due to family upheaval. You can download a manual from the BAMA site,
which should give voltage and resistance norms.

Side note: The crystal filter also appears not to work. Basically, it
behaves like an open...nothing gets past it, unless bypassed by the
switch. Do these particular crystals tend to deteriorate and die with
age? What do you replace it with, a crystal ground to the IF freq?

I'd be interested in corresponding with somebody who has been successful
in restoring one of these radios. My email address is

hpf atsign gainbroadband dotcom

Thanks,
Pete
AC7ZL