Yes. With fuses in the bulb is bright - probably about 75% of what it's capable of. In case it's relevant, as previously mentioned, the panel lamps are quite dim with the fuses in place but with fuses out, are somewhat brighter.
Old Q8 and Q9 had insulating discs underneath them which I used for the new ones. Q3, Q5, Q10 and Q11 had no such discs so I mounted them flush with the board.
By "electrically isolated" do you mean a continuity check from transistor housing to chassis ground with the amp powered off or some other method with the amp power on?
Thinking continuity and with amp off, I tried that with this DMM I'm not yet familiar with. I can make it produce an audible tone when continuity is present. Placing black meter lead to chassis ground and red lead to transistor case, I checked all of the TO-3 transistors. The result was, I thought, unusual.
Hard for me to explain and may not mean anything, but;
The chassis ground point I chose for the black meter lead was one of the screws holding a right channel output transistor to the heat sink. Touching the case of all TO-3 transistors produced no sound except Q10 on the right channel. I switched ground points to a transformer mounting bolt and repeated the process, but this time, no sound was produced by touching any TO-3.
The tone you hear can be short in duration or continuous - if continuous that may be a problem but if it is short in nature that may not be a problem. What readings are you seeing?
Switching back to the first ground point, I repeated once more and again heard the tone touching T10.
I moved the black lead to an output transistor screw on the other channel and the sound was made by that channel's Q10.
Sound was only made using a ground screw in one row of transistors in each channel, not the other. Or, anywhere else.
