jeromach
With sufficient thrust, ducks fly just fine
I got this amp at my bench with just the question of giving it a check.
I already learned from here the issue with the infamous c607 cap, but there's still some thing that made me wonder;
DC offset at right was ok 1,4mV, but at left 62,3mV. I could correct that without a problem.
The bias voltage for both left and right was low, 2,6mV, that could be adjusted to 10mV, although these trimpots are not the easiest to adjust.
But then the power supply voltage (B- measured). That should be around -55 Volt, but it was -66,4 Volt and could not be adjusted lower than -57,8 Volt. It even made noise that diminished
with lowering the voltage (the transformer that is I guess). Could that have anything to do with this cap being bad?
It was clear someone else already worked on this amp, one of the bridge rectifiers had been replaced and it was missing some screws (I hate that!), so I just wonder if the original PS cap is still
in (I think so, since I can see bursts inside), so would this be the original?
I already learned from here the issue with the infamous c607 cap, but there's still some thing that made me wonder;
DC offset at right was ok 1,4mV, but at left 62,3mV. I could correct that without a problem.
The bias voltage for both left and right was low, 2,6mV, that could be adjusted to 10mV, although these trimpots are not the easiest to adjust.
But then the power supply voltage (B- measured). That should be around -55 Volt, but it was -66,4 Volt and could not be adjusted lower than -57,8 Volt. It even made noise that diminished
with lowering the voltage (the transformer that is I guess). Could that have anything to do with this cap being bad?
It was clear someone else already worked on this amp, one of the bridge rectifiers had been replaced and it was missing some screws (I hate that!), so I just wonder if the original PS cap is still
in (I think so, since I can see bursts inside), so would this be the original?