I meant to say earlier that the amp is a Gamma Acoustics Rhythm amp. Theres so little out there about these amps - 1 or 2 mentions and thats it!
Anyway I did some more looking tonight and sorted some issues and found more. First off, the bridges for the heaters were cooked. There was 1 bridge for each 211 and then 1 for all the 12''7 valves. The 5687 runs off AC heaters. So I replaced all those and at least now all the heaters were working. So then I decided to check the B+. I get 1050V at the plates of the 211s (which seems correct). But I had only a couple of volts going to the PCB you see in the pic above which holds all the input and drivers. So anyway long story short, the 1050V B+ is filtered down using a massive 50K 50W resistor and it had gone open circuit. You can see a the big resistor in the middle pic above (theres 2 similar sized ones together in the pic).
What the hell could cause a 50W resistor like that to go open??!? Its a worry!!!
Also, I've carefully (visually) checked all the components on the PCB and other than the rectifiers, there's no sign at all of anything overheated.
So I'm guessing that the input/driver circuits are looking for about 300V or so. That would mean that if a 50K resistor provided a drop of ~700V, the resistor is throwing off ~11W or so.
Any comments? To quote pink floyd "is there anybody out there?"
Fran