[EdHolland]

More investigation yesterday. Carefully (and with some difficulty) I was able to remove the can from around the first IF transformer. Before this, I tested its continuity to the chassis again, and grounding did seem precarious. Inside, there was no obvious damage from the short, but the trimmers were very dusty. Wiring and wax dipped coils all looked good. On the inside of the can, there is one spot that looks to be where the flash-over occurred, at a position near the trimmers, and coincident with the high voltage locations. No sign of what caused the trouble.

This will give an opportunity to replace the slightly shabby wire to the grid of the #78 IF valve, and perhaps the other wires running under the chassis. I may get it running again this afternoon.

The transformer is interesting. Two coils, spaced quite far apart - perhaps ~3/4" - wound on a wooden dowel and dipped in beeswax. The compression trimmers are carried on a square ceramic support attached to the dowel.

Cheers

Ed