Dove right in! Help with RCA 21-D-8628

[Electronic M]

Originally Posted by old_coot88

The replacement xfmr also has to have the dedicated 5 V filament winding for the 5U4.

That's in addition to the 6.3 V winding.

If you don't mind not having the 5U4 you could get a transformer without the 5V winding and use a pair of 1N4007s in place of the 5U4. I've been known to make Solid state 5U4 substitutes and use them in sets where the original transformer runs hot to reduce heater load and cool the transformer.