A couple more Voyd power supplies that were in need of some tlc.

On the left a late version split phase PSU which had failed on one phase. As it is about 30 years old, all the electrolytic caps were replaced, along with the darlington outputs and the small FETs. A couple of the resistors have a tendency to overheat, so they have also been replaced with higher power types.



On the right is a very old PSU, about the oldest type I have seen to date. The design and layout are both very different from the later units, but unfortunately it had a history of failure so it was decided to rebuild it as close as possible to the final design, like the unit on the left.

This meant a new mains tx to reduce the rail voltages, replacement of all the old electrolytic caps, the addition of voltage regulators for the oscillator and preamp stages, and a complete rebuild of the power stage.

The confined space and design of the original layout made it an interesting challenge, but all seems to have worked out nicely.