[MRCA] BC-348 Help

[J Mcvey]

 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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