After pin 6 on the driver board drops to near 0v, do you see rail to rail oscillation on the output transistors? The oscillation will be on leg 3 of half of them and leg 2 of the other half. You may have to drive an audio signal into it to make it oscillate.
Set the scope to 5us and 50v/div. You may have to adjust the trigger level to get it to lock on the waveform.
If you do see oscillation, do you have audio on pin 1 of the audio driver board?
Set the scope to 5us and 50v/div. You may have to adjust the trigger level to get it to lock on the waveform.
If you do see oscillation, do you have audio on pin 1 of the audio driver board?
not getting any oscillation on any legs of output transistors or on pin 1 of driver board, driving input with 41hz tone
Pin 1 should have normal audio.
Do you have ± regulated voltage on the power supply pins of the op-amps?
Do you have ± regulated voltage on the power supply pins of the op-amps?
For an 8-pin op-amp, it's pins 4 and 8. 4 should have negative voltage and 8 should have positive voltage (approximately ±15v).
It appears that the +15v regulator is defective. You'll have to determine what's being used for regulation. I don't have any information on this amp. If you can't find the regulator, post a photo of the entire board.
- Status
- Not open for further replies.