[Phil G4SPZ]

For what it's worth, I have acquired a couple of original Tele F wooden carrying boxes, and coincidentally I fitted the phones into the boxes earlier this evening! All I need now is some proper webbing carrying straps...

If all the rest of the circuit checks out for continuity, I agree that C2 could be open-circuit. You'll probably obtain a suitable replacement from Maplins; 2.2uF will be fine. They sell these for audio applications.

Regarding the carbon mic inserts, someone once advised me that these can absorb atmospheric moisture through the little pressure-equalisation hole behind the diaphragm, and gentle warmth from a radiator or airing cupboard for a few days might dry it out and evaporate the moisture. It didn't help in my case, and I managed to find another insert that was better.