Redkarter
Active Member
Edit: well now I feel a bit silly for posting, after looking a bit more closely I found r53 to be open. After replacement the bias is tracking closely to the other channel when signal is applied.
Back again unfortunately with what is hopefully the last issue on this unit.
During my adjustments and output testing I noticed that the bias voltage is not increasing (or only increases a tiny amount like .1mv) respective of the channels output on one channel.
Bias has been adjusted at idle to 10mv on both channels. Output on both channels is symmetrical and produces a clean sine wave. I have replaced a few parts in this when initially getting this unit including tr19 which i believe is the biasing transistor, the bias pots, all electrolytics and one resistor R67 was replaced as it was burnt. Emitter resistors were also changed.
I did compare several resistances and all seem comparable (namely r37,45,55,57,67 and 69 but several others were checked as well) ,and diode checks on the diodes in the area responsible. Any thoughts or where I should look next or how to track this down a bit better?
Back again unfortunately with what is hopefully the last issue on this unit.
During my adjustments and output testing I noticed that the bias voltage is not increasing (or only increases a tiny amount like .1mv) respective of the channels output on one channel.
Bias has been adjusted at idle to 10mv on both channels. Output on both channels is symmetrical and produces a clean sine wave. I have replaced a few parts in this when initially getting this unit including tr19 which i believe is the biasing transistor, the bias pots, all electrolytics and one resistor R67 was replaced as it was burnt. Emitter resistors were also changed.
I did compare several resistances and all seem comparable (namely r37,45,55,57,67 and 69 but several others were checked as well) ,and diode checks on the diodes in the area responsible. Any thoughts or where I should look next or how to track this down a bit better?
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