I'm looking for the service manual for the Counterpoint SA-3000 Preamp. I know the designer used to sell it, but he has since closed up show.
The particular problem I'm having is that the IREF LED, LED503, is not lit, which indicates the high voltage section is not functioning. In addition, the 555 timer that switches the relay is not turning activating. These things worked before a recap, so I suspect I lifted a pad, but I need to know where.
The particular problem I'm having is that the IREF LED, LED503, is not lit, which indicates the high voltage section is not functioning. In addition, the 555 timer that switches the relay is not turning activating. These things worked before a recap, so I suspect I lifted a pad, but I need to know where.
IREF LED, LED503, is not lit, which indicates the high voltage section is not functioning.
In addition, the 555 timer that switches the relay is not turning activating.
It's probably the timer circuit. If the timing capacitor is a large value electrolytic,
you may have to use a special low leakage type for the circuit to work properly.
The capacitor leakage "resistance" has to be much larger than the timing resistor feeding it.
I should be looking for a cap with a large ESR?
No, something like these. If the timing resistor is say 100k or more,
this could be the problem. It's happened to me before.
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