[Milsurplus] BC 348 Question: in re lifted B- lead

[WA5CAB at cs.com]

I can't vouch for the original BC-224 but all models from BC-224-A through 
BC-348-S have the B- above ground.

If you mean if the radio is modified with an AC operated rectifier supply, 
you simply connect the B- from the rectifier supply to the same point where the 
dynamotor B- connected.  So B- would be floating in the power supply.  Filter 
capacitors, however, should still go to chassis, not the B-.  If using a 
conventional center-tapped HV winding and a full wave rectifier, the center-tap 
would go to the B- connection in the radio.  If using a bridge rectifier, the 
negative terminal of the bridge would go there.

If you try to use a substitute dynamotor (more DM-28 filter-bases turn up 
than do the actual dynamotors) you must use one that has the B- brush holder 
insulated like the B+ is.  Or take two to make one.

In a message dated 3/8/2009 3:58:27 PM Central Standard Time, 
bluebirdtele at embarqmail.com writes: 
> Now I'm starting to build up a file on the BC 348.
> Can someone tell me which versions have the B- line off of ground and why?
> What do you do to the power supply wiring to compensate for this?
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480