> From: wasteking1
>
> you were right--i was testing with the master volume slider--- using the
> assignable volume it cuts out at about 40% of the way up . At the risk of
> sounding even more stupid-- i was wondering how i would check for negative
> voltage --crossing pin 7 with what? ground? and my simple anaolg needle
> radioshak meter showed +3 volts when i crossed from the battery
> to pin 7 on all zx03 chips. [ but i could try swapping Zxo3
> chips if they are the likely source] ..i assume
> that voices 1-6 correspond to chips numbered z2o3-z703 in the 'X'
> place . of
> course that places chip Z203 under the output board requiring
> unscrewing the
> whole main circuitboard.

To measure negative voltages with an analog meter, just connect the positive
input to the meter to ground somewhere, and use the negative input to probe
the op-amp outputs; the negative voltages will show up as positive values on
the meter. If you have a digital meter, then it'll have a minus sign.

If the chips are socketed, then, yes, swapping them is a good way to find
bad chips. It's unlikely to be the capacitors, because leaky capacitors pull
the voltage toward ground, not toward the minus rail.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...