Recently purchased a Tek 2235 (does not have military option). It displays both traces ok as well as a square wave on both channels. Both traces respond to the 'A' intensity control, while the 'B' intensity control has no effect. Has anyone else experienced this problem? Both the 'A' & 'B' intensity control pots check out ok. Voltage at the base of Q814 varies when the 'B' pot is turned as well as the output voltage on the emitter of Q814. Voltages here are correct too. There is no voltage change at the node of anodes CR818 and CR820 while turning the 'B' pot, but it does change here when the 'A' intensity pot is turned. I've checked all related diodes --CR818, CR820, CR805, CR817, CR816, CR680, etc., and related resistors. Q586 is biased and stays on in "Ch1", "CH2", and "Both" positions, at least as far as I can tell with the voltmeter. I don't see any components with visible damage, but there is a place on the board that is brown from heat around Q254, Q255, Q256 which is the Vertical output to CRT section. I'm guessing that this is unrelated to the intensity problem. any help or ideas would be greatly appreciated.
Thanks, John