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Not getting anywhere with this. I’ve replaced the 8FQ7, which has no effect. Test point 17 shows a good waveform. At test point 3, it also looks good until I move the switch from stby to on, then the peak to peak voltage drops from 12 to 7.6. At test point 5 the peak to peak voltage is around 90, it should be 120. I’ve tested all the resistors around Q1 and Q2 and they appear fine. In my version the B-13 rail also powers Q4 and the J/K flipflops. Other than that I can’t find anywhere else it is used. I also checked the resistors that are used to form the negative rails, they are all fine too and I replaced those capacitors.
Just in case I tried a different cap to pin 3 of the 13GF7A, it made no difference, and anyway voltage on that pin is fine.
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