Hi Fisher wizards, I just repaired a Fisher X-101-C for audiodon. He has been using this Fisher in his bedroom and it will be handed to one of his daughters somewhere down the line. Either Don or Dave Gillespie put EFB into this 101-C as part of an overall restoration. This unit got a full restoration but it's not Don's other X-101-C that Dave extensively redesigned. A few weeks ago, Don told me that one channel dropped out. It turned out that a Jensen 0.047uF 630V coupling cap with copper foil in oil had turned into a resistor. I ordered and installed a replacement cap and the amp seems fine now. (see note below) I'm looking for some guidance on adjusting the Bias and AC Balance pots before bringing it back to Don. The Service Manual says nothing about that. I haven't been able to find an owner's manual but manuals for other tube Fishers tell you to bring it to a tech for AC Balance adjustment. I have Dave G's "X-101-B Mods Rev B" schematic. The 101-C has 10 ohm cathode resistors. The voltage across them shows that the four output tubes are running at 28mA (3 tubes) and 33mA (1 tube) at a line voltage right around 120VAC. Should those be running a bit higher than that? Dave shows 34mA on his schematic. And what about that one tube running a bit higher? I assume it's the tube itself. I may just leave the Bias control where it is to avoid running that tube too hot. On the AC Balance adjust, I noticed that the Left channel pot was almost all the way to one end while the Right channel pot was close to centered. The bad cap was on the Left channel so maybe that cap was problematic all along before it failed completely. I set the Left AC Balance like the right one before testing the amp. I have all the tools/toys needed to adjust this including a Keithley 2015 generator and THD analyzer, a scope, dummy speaker loads, etc. I should be able to put a 1KHz 0.5V sine wave from the Keithley into the inputs and read THD across the speaker outputs connected to resistors, right? I did a quick run of that with speakers connected and got about 0.8% THD on each channel. I know it would be more accurate with a resistive load on the speaker outs. Thanks for any guidance. I want this X-101-C to sound good and work well for Don and his family. --Dan Note: This unit was taken down by a failed boutique coupling cap. Don's X-1000 also was taken out by a failed Mundorf Mcap coupling cap. I repaired that as well and it's fine. However, I'm a bit skeptical these days about the reliability of fancy coupling caps. For $33 and $44 respectively, these should last longer than they did. Are Russian PIO caps more reliable? Has anyone had similar experiences? If that turns into a big discussion, let's start a different thread in the "Tubes" forum. Thanks.