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Hello,
Trying to figure out how 10 vdc is getting in the 0 vdc rail. This condition was exhisting when the amp was given to me. When I opened it up I found the bias transistor bad so it got replaced along with Q204 and Q205. I also replaced the power transistors with 2SA1962 and 2SC5242, all coupling caps. All diodes were pulled and checked.
When the amp is first turned on, with no load, my DVM shows 58 vdc at the speaker jack, then quickly drops to 10 vdc. All other test voltages line up, except for the zero volts at R223.
Any help would be greatly appreciated.
Thanks.
Ampeg_B115_B410_B40 Schematic.pdf
Trying to figure out how 10 vdc is getting in the 0 vdc rail. This condition was exhisting when the amp was given to me. When I opened it up I found the bias transistor bad so it got replaced along with Q204 and Q205. I also replaced the power transistors with 2SA1962 and 2SC5242, all coupling caps. All diodes were pulled and checked.
When the amp is first turned on, with no load, my DVM shows 58 vdc at the speaker jack, then quickly drops to 10 vdc. All other test voltages line up, except for the zero volts at R223.
Any help would be greatly appreciated.
Thanks.
Ampeg_B115_B410_B40 Schematic.pdf