Note to all:

The complete manual for the BC-348R can be downloaded from the BAMA
mirror site:

http://bama.edebris.com/manuals/military-kg7bz/bc348/

Scroll down and click on:

TO 12R2-3BC-112.pdf

(Maintenance manual for BC-224-F, K, BC-348-H, K, L, R. rev. 11
February 1955)

This is a 10 MB PDF, so it will take a little time. Lots of other
manuals there, too.

http://bama.edebris.com

On Jul 3, 10:16?pm, Engineer wrote:
On Jul 3, 11:29 am, wrote:
On Jul 1, 9:57 pm, Engineer wrote:
Those Dern Black
Plastic Capacitors. These are small units that look like micas but are
actually paper, and they are notoriously unreliable.

************** I did not know that, I thought they were micas!

Me too. They are reliably unreliable. That doesn't mean the
ones in yours will fail, it just means they have a bad reputation.

*************** Yes, I found this out early on when I saw that the
6K6 cathode went to ground. Smelled a rat and checked it out! The
6K6 stays properly biased with my ext. P/S.

You figured it out a lot quicker than I did!

? 3) The receiver isn't meant to drive a speaker. Not enough audio
gain,
and pushing the set to do so makes it sound awful IMHO.

************** I'm using a matching transformer from 300 ohms (LO) to
8 ohm speaker. I plan to install a proper OPT to match the 6K6 to 8
ohms but leaving the original there for posterity.

The trick is that the 6K6GT isn't biased the way it would be to
deliver a couple of watts as a speaker driver. Sure it will work, but
it will be running flat out.

There are three options:
A) Use only headphones, as was intended. You have a choice of 300-600
ohms or 2000-4000 ohms by changing transformer taps
B) Modify the audio chain to a more-conventional design

*************** See above.

C) Use an external audio amp, with an appropriate resistor load to
avoid frying the output transformer.

************** Not a bad idea... but needs etra bits!

Put them in the PS unit and put the whole thing in a speaker cabinet.

With a little care, you may be able to
avoid wiring changes in the rx itself by making up a dummy chassis to
replace the dynamotor, and powering the rx through the rear plug, with
the AC mains switch on the power supply.

************** I want to leave the dynamotor in the chassis "as is"
and have an external AC heater supply.

The problem with that is the dynamotor, if not running, will present a
near-short circuit to the power supply. And the 24 volt heater line is
connected to the dynamotor input, so it will be shorted too.

By simply removing the dynamotor assembly and putting in a dummy
chassis so the loose wires don't short, you can retain the rx wiring
and run from an external supply. Then if you ever want to drop in the
dynamotor and run from 24 volts, you can do that too.

************** Thanks but, amazingly, all tubes test "good" to "good
plus"

Not amazing, really, If the set wasn't used much, the tubes could be
almost new.

************ PS: I'll email you for the manual.

I can send as an email attachment but it's 10 MB. You can also
download it from the above site.

73 de Jim, N2EY