[DMcMahon]

All back together and playback and record (only checked microphone, still to check DIN line recording) working well, so the output transformer survived the abuse.

Interestingly the HT & LT supply voltages went more abnormal the longer the bad valve was left in/powered, with the HT getting up to 320 volts and LT down to -2.5 volts

With the replacement valve (taken from the bias oscillator) and the bias oscillator valve replacement by borrowed EL 42 from my TK 819, the HT and LT voltages returned to more normal values. i.e. HT +237 volts and LT -27 volts.

Hard to know what caused the bad EL 42 to go bad, maybe just old age failure or maybe helped along by the previous shorting down of the reservoir capacitor event (I think that might actually have been a red herring).