[MRCA] BC-654/SCR-284

[mac]

Yes, the vibrator PS (PE-104-*) powers the receiver and also an xtal  
calibrator down on the transmitter chassis.  And yes, there was a  
battery that fit in the same hole.  Made life easier for the guy  
cranking the GN-45-(*) when operating in that  mode.  The 307-A tubes  
are power pentodes (not "beam" tubes), forerunners of the 2E22  
pentodes used in the GRC-9, 1306 and later TBX radios.  Originally  
used in 1930's police mobil radios I read somewhere. Heaters specked  
at 5.5 volts. Pair in the PA,  suppressor grid modulated when  
operating in the phone mode.

The rig is loaded with those black molded paper caps that give us so  
much trouble.  Many of these are used to bypass the low voltage  
filament circuits and I have gotten away with leaving these in place  
in the half dozen of these radios I've restored. Replace all the  
others, though.  The PE-104 will have to be rebuilt too.  Complex  
radio for what it does as you will see when you get into it.  Works  
quit well, though. On request can provide a DVD of one of these in  
action along with a bunch of other radios at one of our MRCG FDs.  We  
also run  one of these radios in our 3/4 ton command car at Ft.  
MacArthur.

Dennis D.  W7QHO
Glendale, CA

***************
On Jun 28, 2011, at 6:20 AM, Ray Fantini wrote:

> Traded a couple items I had laying around the house for a BC-654/ 
> SCR-284 transceiver. Although I have been doing this stuff for a  
> while now this is the first 654 I have owned and there are a couple  
> questions. First, this radio has the vibrator pack that I assume is  
> for powering the receiver. Is there a battery pack that fit into the  
> same location as the inverter? I know that I would have to build up  
> a battery but wondered if that was the original intent. 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? Third, are the filaments in the  
> transmitter section derived from the receiver inverter? Or are they  
> developed from the six or twelve volt sources? Noticed that most of  
> the tubes in the transmitter are three volt and all in the receiver  
> are one point five. Have downloaded the schematics but not had much  
> time to look at them yet. Last but not least this radio appears to  
> have never been used, has all the spares and
>  is in very good condition but is missing the case. Going to assume  
> that no one has a spare case so looks like I may be building  
> something to house it and will also have to find the connector that  
> mate with the one on the front of the radio. Are all the voltages  
> for both receiver and transmitter brought out to this connector or  
> just the transmitter and the six or twelve volt source? And anyone  
> have one of the connectors?
>
> Ray F. KA3EKH
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