[Radioroslyn]

As Tim mentioned these early tetrode mixers can be a bit fiddly. Reading the service notes tells me that it's a bit touchy in regard to the wiring layout. Sometimes doing an alignment to the IF and osc stages will help after you've done some parts replacement as these are slightly different from the originals. That's the long answer.

If you want to experiment a little take two pieces of insulated hookup wire and make a gimmick capacitor by twisting them together like 3-4 times. Connect by soldering(clip leads add stray capacitance and inductance) one wire to what you where touching to make the set play and the other to the chassis. Add more twists and see if you can get the osc to start reliably. If you get a bunch of twists and it works ok you could replace it with a trimmer cap.

Have Fun!