General Radio 1203-A/B Unit Power Supplies

I restored a pair of General Radio Unit Power Supplies, a 1203-A and a 1203-B.

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They both needed new power cords.

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This is the 1203-A, with tag-board construction.

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This is the 1203-B.

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I got to use my Chinese-imitation Heyco pliers on the line cord strain reliefs. They work well enough, especially for the price.

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There’s not much to go wrong with these supplies. The filter capacitor is likely to be the only troublesome component.

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This was a good excuse to put to use the HP 428A Clip-on Milliammeter that I bought from Chuck Ochs at one of the NEARC meets.

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At 70 volts, ...

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… the filter cap (in parallel with the 120 KΩ bleeder) was pulling 16 mA. Definitely leaky.

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So it was time to take photos ...

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… and start disconnecting the filter caps ...

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… so that I could re-stuff them.

I  removed the cans, cut them open, re-stuffed them, and reinstalled them. I’ll have to go back and take some photos of the finished job.



© Steve Byan 2011-2016