[Diabolical Artificer]

That big cap/can should be fine, it's probably a Bosch. Take the ECL86's out, leave the radio valves in and power the gram up through the LL whilst monitoring the voltage on the big can. As I said in a previous post it's possible to monitor current if you take the fuse out which is on top of the mains tfmr.

A better way would be to stick another meter in the AC line to monitor current, if current draw goes over 150mA and heads to 200mA switch off.

Clip your meter leads onto the big can etc before you power up so your hands are away from live parts. If you do, do any probing, use your right hand.

Meter or meters in place, the one in the AC mains in set to AC current, the big cap set to DC volts, switch on and keep an eye on things for 10 minutes. DC volts should go up, then down and stay stable, but as the gram hasn't been powered up for a while, volts should steadily climb. AC current should go down. Then leave powered up for a few hours whilst still being not too far away, keep checking V and I occasionally.

If all is steady, take the LL out of the circuit and power up - same meter arrangement, same pack drill. Keep your hand near the switch, any smoke, kill power.

There's a selenium rectifier that may die, near the mains tfmr I think, have a feel now and again (on the body, not the terminals! : ) see if it's getting hot, if so, kill power. Being German made, most of the components are good quality, so you shouldn't need to change much

If all well insert the ECL86's. Good to change C802/807 and C748 and C758 though, as you've done. To check the triode section of the ECL86 red probe on pin 1 black probe to chassis. The triode section is grid biased, (R727/737 will be worth checking) so you should get a negative reading, EG -2v say. If it's positive, switch off. To check the pentode, red probe pin 7, black still on chassis . There should be about 5 volts, positive 5v that is.

Hope that helps, Andy.