hello everybody!
i just got another defective amplifier to repair. it starts clipping very early at about 0,6V AC. i desoldered all transistors in the output stage and all were ok in diode and hfe check with a DMM. do these checks verify that the transistors are okay? where else could the problem of the amplifier be?
i just got another defective amplifier to repair. it starts clipping very early at about 0,6V AC. i desoldered all transistors in the output stage and all were ok in diode and hfe check with a DMM. do these checks verify that the transistors are okay? where else could the problem of the amplifier be?
It could be anywhere prior to the output transistors.
I would whip out the other transistors and check them and while they are out check the other discrete components.
I assume you have checked the dc supply voltages ?
I would whip out the other transistors and check them and while they are out check the other discrete components.
I assume you have checked the dc supply voltages ?
First check the input stage, ie signal transistors and/or opamps. I once fixed an amp that insisted on distorting the right channel a lot earlier than the left. Pulled out all the signal transistors and one checked out as having a beta of like 10 vs 150+ for all the others. Sure enough, replacing that transistor made the right channel operate to spec.
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