Greetings! I'm looking for a in - depth tech book on the BF/SF (aa764 circuit) Fender Champ. This is not for a Vibro Champ, just a plain old vol, bass, treble, vanilla Champ. A detailed book that fully breaks down the circuit and explains what the caps, resistors, tubes, do in the circuit. What the voltages should be at the tubes, filter caps, etc. Some troubleshooting information would be awesome. A book that will let me check the health of the amp circuit. Not asking too much, right??