Hi Perry,
I found the audio signal on the driver board at R32(blue) but it doesnt appear on the other side of the resistor
I found the audio signal on the driver board at R32(blue) but it doesnt appear on the other side of the resistor
An externally hosted image should be here but it was not working when we last tested it.
OK, if driven hard enough, you should see signal on the output of the TL072 and the output of the LM311.
did some searching on the driver board, found no -5v present, traced it back to an inductor that may be bad.
Replacing the inductor seems to have sorted the drive issue, have drive present on both high and low side. the low side drive seems drive wave is smaller than the high side.
Do you have 12v across the collectors for both the high and low side driver transistor pairs on the driver board?
Assuming that the 10v is for the low-side...
The 10v probably won't explain the entire difference but you need to check the output of the 7812 regulator. Place the black probe on its ground terminal and measure the input and output voltage for that regulator.
The 10v probably won't explain the entire difference but you need to check the output of the 7812 regulator. Place the black probe on its ground terminal and measure the input and output voltage for that regulator.