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This piece has very low volume. Took it apart and measured voltages off tubes. Pin1 -5.87, pin2 -11.16, pin3 -11.42, pin6 0, pin7 -10.39, pin8 -10.64. Now I know these are very low, and according to schematic I should have around 170v. Where should I begin looking in the power supply for trouble. Thank you in advance for your help. Danny
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Are transistors Q9 and Q10 being used as a switch, and should I start looking there. -
Those transistors are just voltage regulator pass transistors. Are all of the other voltages ok? The 75 and the -12?
The 170 volt supply is turned on and off via the standby switch. Have you checked the switch? Are there 220 volts on the switch terminals?Comment
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Thanks for the response. I will try to make those measurements later this evening or in the morning. Im playing tonight so wont have much time. Thanks dannyComment
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Ok the 75v and -12v are ok. I have 236v at the switch, but even when the switch isnt turned on still have that low volume either way.Comment
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Heres something that just happened. I was trying to measure the voltage on the base of Q10 and accidently shorted the base and emitter together, i got my volume back. Voltages for Q10 are Emitter 236.5v, Base -318.6mV, Collector -0.876V. Im thinking replace Q10. Does that sound right. Thanks DannyComment
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Apparently either Q9 or Q10 has a problem turning on. Check all three transistors (Q8, 9, 10) and check all of the related diodes as well.Comment
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Somebody must have worked on this thing before I got it because Q8 was installed backwards. According to the PSU Loading diagram the way they had it installed was correct. But according to the schematic it was incorrect. So anyway pulled it out installed a new one and I have volume now. Thanks for the reply DannyComment
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