[MRCA] BC-348 Help

[MilComm Guy]

I am running my BC-348-N on a 6 amp 28v supply with no issue, radio is
stock w/dynamotor.

K1HF

On Sat, Feb 9, 2019 at 4:30 PM J Mcvey via MRCA <mrca at mailman.qth.net>
wrote:

> the run surrent is only an amp or so. the current draw comes the instant
> when you first start it. that can be alot higher. If your supply has a
> touchy OC shutdown or there is abnormal current draw from the radio, you
> might have issues getting it to go. Otherwise,clean the old grease out with
> a tooth brush and alcohol and re re-grease it. If it has a lot of hours on
> it, ther may be  carbon dust that needs to be blown out and cleaned up.
> Hopefully the commutator doesn't look like an hourglass...
>
> Also those radios were designed to work on 28V , so you might consider
> jumping the 2 series heater ballast resistors so that the heater strings
> are up to voltage. Otherwise you will notice a slow warmup and slightly
> impaired performance. slightly lower B+ doesn't seem to matter much.
>
> On Saturday, February 9, 2019, 2:53:22 PM EST, DSP3 <jeepp at comcast.net>
> wrote:
>
>
> Brian, Your 10A supply is quite sufficient, assuming all else is OK with
> the radio.  If your radio is other than a J, N, or Q model (those are more
> reliable, capacitor wise) you may want (need) to do a re-cap, to those
> include inside the 4 modules, the crystal filter and BFO cans.  Capacitor
> shorting or leakage can be detected by measuring the B+ current.  It should
> be from 50 to 80ma under operation.  More than 80ma at 220v indicates
> potential excessive current.  Current can be measured at the dynamotor
> connection strip.  Simply remove the B+ wire and insert a milliammeter.
> Bring the radio up with a variable DC supply, if available.  If not, then
> just monitor the current and shut down if something is untoward.  I have a
> dynamotor simulator chassis that I mount in place of the dynamotor such
> that I can monitor filament and B+ draw from an external power supply.  The
> above is what I go through for each BC-348 I service.  The re-cap procedure
> is not too tough but does require time and attention to detail.  I did an
> article for ER magazine that goes through all this.  Its sometimes pretty
> amazing how these receivers come to life after some TLC.  If I can assist
> with info, please let me know.
>
> Jeep - K3HVG
> On 2/9/2019 2:36 PM, Brian Roberts wrote:
>
> 
>
>
> Hello Gents--
>
> I've acquired a BC-348R and it appears to be unmolested.   It still has
> the dynamotor in it and I'd like to get it going again in its original mode
> of operation with the dynamotor.   I'd like to solicit opinions and help
> from guys who have gone down this road before as far as things that must be
> done, and any hints and kinks on how to do them.   I'm sure the dynamotor
> will have to be cleaned and lubricated for openers and that will be a new
> task for me.   Another area of concern is how much amperage will be needed
> to start and then run the set?   I've read anywhere from 8 to 50 amps!    I
> have a 10 amp 24 VDC power supply available, but I don't think that will do
> the trick to start the dynamotor.   I'm thinking about putting two 12 volt
> batteries in series to start the set, and then once the dynamotor is up to
> speed switching over to the power supply.   Again, I'd like to solicit
> comments on that idea.   Thanks.
>
> Brian K9VKY
>
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