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.

IMG 3631.jpg

They both needed new power cords.

IMG 3630.jpg

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

IMG 3629.jpg

This is the 1203-B.

IMG 3631.jpg

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

IMG 3633.jpg

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

IMG 3636.jpg

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.

IMG 3637.jpg

At 70 volts, ...

IMG 3638.jpg

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

IMG 3639.jpg

So it was time to take photos ...

IMG 3640.jpg

IMG 3641.jpg

IMG 3642.jpg

IMG 3643.jpg

… and start disconnecting the filter caps ...

IMG 3644.jpg

IMG 3645.jpg

IMG 3646.jpg

… 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 2011-2019