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All knobs set to 5 except for reverb (0). "Bright off" and "Hi lead" off. "Rhythm" knobl engaged. When I switch between the "rhythm and lead" switch (crossover), the lead channel (and only the lead) sounds like a capacitor discharging (slowly fading then breaking up in to a high frequency pulse). Can this be a result of bad coupling caps?
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I find it odd that both channels share the same tube for their first input gain stages. Also I see that both plates are common thru 100k supply resistors, since there is no bypass/supply filtering at that point. A small cap there would kill any signal combining going on there, if a scope shows it in that circuit. -
WRONG SCHEMATIC! Updated though...
I am sorry about the vagueness of my previous post. I didn't have much info or testing to go off of and I should have held off until I had more of the problem. First of all, I posted the wrong schematic last night. I have found the correct one and have attached it. I also marked on the schematic where I have tested with the scope and what I have found. at the base of Q11 and pin 1 (vout) of Chip A2a I have a solid waveform that is not affected by the switching of the lead and rhythm channel. At Q13 I obtain a signal on "rhythm" but when I switch to the "lead", no signal is measured. It then ramps back up (sometimes quickly, sometimes slowly) and occasionally drops out and repeats. If I switch between the two channels repeatedly the signal sometimes remains like nothing is wrong. This behavior to me is a faulty capacitor but I cannot find one to blame it on. Ive checked Q13 and D17 and they test correctly. Though, when I try to read a signal with my scope on either side of D17 the signal cuts out (both on rhythm and lead) and I read no measurement on my scope and no signal passes until I removed the probe. I didn't know that diodes would behave like this (I didn't think so) but its definitely strange to me. Suggestions?Comment
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