[ARC5] Commercially made power supply for a BC946 question

[Ken Gordon]

On 31 Jul 2024 at 10:53, Michael Kana via ARC5 wrote:

> Hi all
> I picked up a nice condition BC946 which had what looked to be a
> commercially made PSU bolted on over the dynamotor connector. It has a
> small form transformer and a 6X5 rectifier. There is an additional
> octal socket that is vacant. Has anyone encountered this PSU and know
> what went in the spare socket?  I can provide pics for additional
> detail if needed. The RX was built by Colonial Radio Corp Thx Mike
> AA9IL

That sounds to me as though it is an early version of a power supply which was, at one time, 
made and sold by Fair Radio Sales. The octal socket contained a plugin electrolytic filter 
capacitor.

Later models of that power supply used silicon diodes in place of the 6X5, and in addition, 
were built on a dynamotor base so it simply plugged onto the dynamotor connector.

The transformer was one which Fair contracted for and bought from some usual transformer 
maker. I don't know who that was, but the transformer output 24 VAC for the filaments, so 
nothing had to be done to the receiver at all. You just plugged the power supply onto the 
receiver by any of a couple of ways, and turned it on.

I had several of those, but sold almost all of them. I think I have one left.

Fair Radio Sales also sold a box with that power supply in it, a small speaker, and switches 
on the "front panel" for BFO ON/OFF, a volume control/power on, and a pilot light. It was 
connected to the receiver by a cable terminating in a connector which plugged onto the 
power connecter on the back of the receiver. They were painted grey.

I kept one of those too.

Might you have a photo of the power supply you could post here?

Ken W7EKB

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