[Ron Ramirez]

Tim, I'm afraid that I don't have the experience with the Fishers such as yours, like those guys at AK have. I don't own a 500-C or 800-C. I do have a 400, my first Fisher tube receiver which I bought at Kutztown two years ago. It is similar in some ways to your 500-C but quite different in others. And I still have a 500-B and a rare 500-S waiting for me.

The output circuitry of the 500-C is quite different from the TA-600, so I can't offer much help other than to suggest reading up on the 500-C at AK.

When I get my 400 and 500-B restored, I might be able to offer up a modicum of advice. But I'm still learning at this point. A Fisher tube stereo receiver is quite different from a Philco 89. At least the output tube circuit in the 89 wasn't designed to run the 42 tube at (or near) its maximum limit. I think it's great that these guys have come up with ways to increase output tube life in those Fishers, and I will certainly incorporate their ideas into my 400, 500-B and 500-S when I restore them...just as I did with my TA-600 with its IBAM circuit.

Nevertheless...I'm still watching this thread with interest. As old Red Green said so often, "Remember, I'm pullin' for ya. We're all in this together."