Hi friends, I am looking for help to repair a JL Audio 300/4 rev 1 amplifier. The first failure is that it turns on without connecting the remote cable. The second failure is that the output fets heat up and the current consumption increases rapidly. The remote does work. When you activate it, the green LED turns on. I will try to find out if I have a faulty IC. I suspect it is a u600. I don't know if it controls the power control. Regards.
Attachments
Do both the rail and the low-voltage transformers produce output without remote?
Does the amp draw current without remote?
Does the amp draw current without remote?
correct, there is rail and low voltage. The LEDs of the 4 outputs light up except for 1 channel where an LED is open and the current consumption without the output fets is 1.2 amps.
DCV on all terminals of U600. Copy and paste the following and fill in the blanks:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
On the lm324, 12v was missing on pin 4, the connection was lost and I recovered it and it worked correctly with the remote.
Correct, I cleaned it with isopropyl alcohol and checked the lines, finding that the 12v did not reach pin 4 of the u600, it was recovered with a small bridge, now I only have to recalibrate the bias.
I managed to get it to play sound for a moment, I just finished assembling it and it no longer played. In the D500 and D501 rectifiers, how much voltage should I have?
I don't have any notes on that. Do you see a square wave driving the outer terminals of the rectifiers?
U600
Pin 1: 0.93
Pin 2: 6.55
Pin 3: 4.15
Pin 4: 12.78
Pin 5: 6.37
Pin 6: 1.90
Pin 7: 0.0
Pin 8: 12.59
Pin 9: 6.78
Pin 10: 10.72
Pin 11: 0.0
Pin 12: 4.34
Pin 13: 6.44
Pin 14: 0.93
Pin 1: 0.93
Pin 2: 6.55
Pin 3: 4.15
Pin 4: 12.78
Pin 5: 6.37
Pin 6: 1.90
Pin 7: 0.0
Pin 8: 12.59
Pin 9: 6.78
Pin 10: 10.72
Pin 11: 0.0
Pin 12: 4.34
Pin 13: 6.44
Pin 14: 0.93