[Milsurplus] BC-654/SCR-284

[WA5CAB at cs.com]

Further on the PE-104-A, there were at least three variants, differing 
primarily in how many selenium rectifiers they contain.  The two common problems 
with the PE-104 are the vibrator, which like all WW-II and Korean War 
vintage vibrators, will probably have to have the vibraor contacts cleared (which 
can be done externally) before they will work.  And the selenium 
rectifier(s) which will usually have to be replaced with the appropriate number of 
silicon diodes.  Otherwise, they may or may not have leaky capacitors but on 
average won't.

The PE-104 operates off of the vehicular 6 or 12 volt battery, or off of 
the 6 volt winding in either of the two generators (GN-45-(*) or PE-162-A).  
Generally, it was expected that when using the GN-45, you would use dry 
battery BA-43 instead of PE-104-A.  Less work on the grunt cranking the 
generator.  The BA-43 is a metal cased unit that looks almost like the PE-104, except 
that seams are soldered instead of being a rectangular cabinet with 
removable top and bottom covers.  I've had maybe a dozen or more of most everything 
in the SCR-284 but have only ever seen (have) one dud BA-43.

The LV wiring in the BC-654, PE-103 and PE-104 is wierd.  The radio was 
designed to operate off of either positive or negative ground vehicular 
systems.  Chassis is not common for most voltage measurements and common wiring.

In a message dated 6/28/2011 8:45:19 PM Central Daylight Time, 
ranickel at comcast.net writes: 
> On 6/28/2011 8:20 AM, Ray Fantini wrote:
> >   Second, is a 307 a three volt 807? How do you build a beam power tube 
> that works on three volts and a battery feed?
> I can help a little with this question Ray.   The VT-225 aka 307A, 
> RK-75, or CV2612 is a transmitting pentode described as "a 306A with 
> quick-heating 5.5 volt 1A filament" in Ludwell Sibley's "Tube Lore".   
> The plate is rated at 15 watts, with the 3rd grid brought out to a 
> separate pin for suppressor grid modulation, as was done in the 
> BC-654.   They were made by Western Electric, Ken Rad,  Raytheon, 
> National Union and Sylvania.  Audiophiles have become enamored of them 
> (especially those of rare and wonderous "WE" heritage"), so you can 
> guess what impact that's had on tube prices
> 
> Transmitter and receiver power was separate, with the receiver able to 
> operate from a battery and vibrator power supply, while the transmitter 
> required a hand crank generator or dynamotor power supply.   .  Very 
> cool radios with a great history.
> 
> 

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