Wideone, Hopefully, you were measuring across the emitter swamping resistors (see bottom of
page 2 of this thread) and not measuring the output of the speakers terminals when you adjusted, otherwise
bad things can occur. If you adjusted the bias current correctly, and the offset
just happened to drop to 30-something mV as it is now, then all is cool. If the amp does not allow for offset adjust, then all you can do is set bias to proper value and cross your fingers. Beyond that it's transistor replacement time (still not a huge deal, BTW).
Opt80, you guys are going to give me a big head. :stupid:
Compared to a lot of guys out there doing this stuff, I'm a hack. However, compared to the average clown at the local TV repair shop, I'd like to think I'm a couple of notches better. As far as my edjmacation, I've a degree in Eng. Technology and a degree in Comp. Science. Most of my career has been spent as a robotics technician in the print industry and in cleanroom fabs (Intel, Moto, AMD, Hitachi, etc, etc..), but I have been fooling around modifying and repairing classic audio gear since the early 80's (before they were classics).
I love this old equipment. I mean, I
really love it. Comparable quality today (if anything is even really in the same league) costs upwards of $1200 for even a simple integrated amp. I was just out of HS when this great 70's gear was being sold, and could not possibly afford it. Now all but the most exteme examples of the best 70's gear are within most budgets.
The problem with the old stuff is that it is, well....., old. Drifting transistors, old high-ESR caps, or leaky caps, and general neglect conspire to see to it that a small minority of those with this old great gear will ever
really know what it is supposed to sound like. My mission in life is to see that they do.