Hello everyone.
I have a Rockford BD500 I am repairing.
Whats been done so far:
All output fets have been changed and gate reistors.
U6 MIC4420CT driver
The amp is squeeling from the torroid and has 36.50 VDC on the positive output terminal.
I am not getting a square waveform on pin 6 of U8.
The drive circuit in the power supply has a nice square waveform.
One half of the amp has square waveform on the gate resistors but is a little hazy, the other side does not.
Why the 36.50 VDC and the squeeling?
Perhaps a bad op-amp TL072C?
I have a Rockford BD500 I am repairing.
Whats been done so far:
All output fets have been changed and gate reistors.
U6 MIC4420CT driver
The amp is squeeling from the torroid and has 36.50 VDC on the positive output terminal.
I am not getting a square waveform on pin 6 of U8.
The drive circuit in the power supply has a nice square waveform.
One half of the amp has square waveform on the gate resistors but is a little hazy, the other side does not.
Why the 36.50 VDC and the squeeling?
Perhaps a bad op-amp TL072C?
I found U17 to be defective. I didnt have any new ones in stock so I replaced it with a used one for testing purposes.
I installed the used U17 and re connected R31.
The amp idles fine now and the DC is gone from the positive output terminal.
The torroid still whines a little but not bad.
I have no sound at low volume but when I turn the volume to half the sound is intermittant cutting in and out very distorted.
I dont have a square waveform on pin 6 of U5 and U8, correct me if I am wrong but pin 3 on U5 and U8 according to the schematic are carriers and should be a saw tooth waveform. I dont have that either.
Should there be DC on pins 2,3, and 6 of U5 and U8?
Not sure where to go next.
I installed the used U17 and re connected R31.
The amp idles fine now and the DC is gone from the positive output terminal.
The torroid still whines a little but not bad.
I have no sound at low volume but when I turn the volume to half the sound is intermittant cutting in and out very distorted.
I dont have a square waveform on pin 6 of U5 and U8, correct me if I am wrong but pin 3 on U5 and U8 according to the schematic are carriers and should be a saw tooth waveform. I dont have that either.
Should there be DC on pins 2,3, and 6 of U5 and U8?
Not sure where to go next.
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