does anyone know the idle current, and the dc offset settings for this amp, i have just repaired it (right channel had blown causing a fuse to blow on the ac primary) but now i think that the pots have gone because measuring the offset one side is 50v and the other is 35v, and its still in protection mode.
can anyone help as i cannot find any information manuals about this amp, ive even tried nakamichi!
thanks chris
can anyone help as i cannot find any information manuals about this amp, ive even tried nakamichi!
thanks chris
You're in the wrong forum... Try analog forum.
To get you started, offset pot is near input differential transistor pair (it could be 5-pin matched and thermally coupled on the same die “single” transistor).
The bias pot should be near drive / output transistors.
These two pots can be used to FINE (!!!) tune settings for no more than 20-30mV DC offset and about 50-100mA idle current; you obviously have the case of shorted transistors in the output / drive stage because your output is sitting at +Vcc (!) Sometimes, the output could go this high if you have a faulty input differential pair...
Yes, check that you have both halves of the power supply rails okay (plus AND MINUS 50V).
Good luck,
Boky
To get you started, offset pot is near input differential transistor pair (it could be 5-pin matched and thermally coupled on the same die “single” transistor).
The bias pot should be near drive / output transistors.
These two pots can be used to FINE (!!!) tune settings for no more than 20-30mV DC offset and about 50-100mA idle current; you obviously have the case of shorted transistors in the output / drive stage because your output is sitting at +Vcc (!) Sometimes, the output could go this high if you have a faulty input differential pair...
Yes, check that you have both halves of the power supply rails okay (plus AND MINUS 50V).
Good luck,
Boky
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