[AMRadio] BC375

[CL in NC]

Can't remember if I posted my luck in finding an almost pristine BC375 at an antique store, thanks to my son, but it is ready to return to the air, if it ever was on the air, it was that clean.  It even came with the 3 connectors, NOS, plugged in the side and a T17 mic.  Tubes were all good, each gave 105 watts out when tried in the PA socket at 900VDC and 180MA plate from my 6 meter amp PS. Following the "Using the BC375 today" article from the web, running at 50 watts out and neutralizing,  the FM'ing was minimized to not readable listening on a HF FM rcvr, and voice with the T17 mic sounds pretty good.  Will found out tomorrow when I check into the Old Friends Net on 3916.  I found the correct PE73C dynamotor from Jon, K1VVC, and it was beat up from 71 years of being kicked around, but when opened up, commutator and brushes looked brand new.  The contactor was bad, found a cold solder joint on one of the solenoids terminals after cutting away
 the varnished cloth wrap.  While I had it open, it was obvious the heavy copper contacts had not one mark on them, never been used before.  I pondered a battery supply, but AGM's were too expensive, and I did not want lead acids gassing in the shack.  I bought a 24V 30A switching supply from a supplier on line, for about the price of 2 good lead acid batteries, and using the suggestion from Brian, KN4R, placed a 1 ohm 50W resistor in line with the 24V line.  In the PE73C's case, just installed it across the heavy terminals of the contactor.  Turning on the PS, spools the dynamotor up to about half speed, and then turning on the power at the BC375 pulls in the contactor and bypasses the resistor for full speed ahead.

Our 'Old Friends Net, has been around for quite a few years and was featured in ER many years ago.  Except for one or two, it's all heavy iron on the air, and several ART13's and ARC5 setups.  Checkins come from all over the South east. We meet on Sundays at 1400Z, and Tuesdays at 1300Z, 3715 +/- QRM.

Charlie, W4MEC in NC