This is a amp that I repaired. It played for about 10 minutes flawlessly but when I turned it down the output fets popped. Never went into protect and was on very good electrical. It belonged to a good friend who also had it on good electrical. At low volume it pops the outputs. No smoking or warning just bang. The power supply is in working order just not sure why it keeps killing the amp section at low volume. Just can't rap my head around why this is happening. Any suggestions
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It appears that it has the 4-driver IC board. Do outputs from the same IC always blow or do they blow from all ICs?
Does it fail with no audio input?
Does it fail with no audio input?
The first repair I had the driver board sent off for repair. Meanwhile I replaced all the transistors for the amp and power supply. Also changed the driver transistors for the power supply. Once I got the driver board back reinstalled it and powered it up. Played on the bench for over a day at low volume. Once in the vehicle it played for ten minutes or so. Only in the vehicle could I have enough supply current to make full power. Turned down the volume and pop there she went. Just never had one do this. Visually inspection of the driver board shows no damage. Thank you again Perry for your response.
Why did you send the driver board to be repaired?
Did they send back your board or simply a replacement?
Did you confirm that ALL gate resistors were within tolerance?
Did you confirm that every regulator feeding the driver board was producing the correct voltage before and after replacing the driver board?
Did you check all of the little green inductors to confirm that all were OK (not open)?
Did they send back your board or simply a replacement?
Did you confirm that ALL gate resistors were within tolerance?
Did you confirm that every regulator feeding the driver board was producing the correct voltage before and after replacing the driver board?
Did you check all of the little green inductors to confirm that all were OK (not open)?
I was unable to get the correct parts from the manufacturer for the driver board. They recommended another shop that was very reputable. The part numbers are ground off for their reasons. The other shop supposedly rebuilt the board.
All gate resistors were replaced on the original repair.
I now have the part numbers for the gate drivers and have them in stock.
I was looking for a possible reason that it played and then when the volume was lowered it popped rather than at full power.
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All gate resistors were replaced on the original repair.
I now have the part numbers for the gate drivers and have them in stock.
I was looking for a possible reason that it played and then when the volume was lowered it popped rather than at full power.
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Pulled all the output fets off. Amp powers up but protects after 5 seconds. Checked the 7812s and getting 130 volts on all three legs, guess that's part of the problem.
Checked all the gate resistors and the larger ones all at 5 ohms. The smaller ones are all over the place. From 4.9k to 24k ohm grrrr. Brown black silver..... Thinking.1 ohm or what.
Checked all the gate resistors and the larger ones all at 5 ohms. The smaller ones are all over the place. From 4.9k to 24k ohm grrrr. Brown black silver..... Thinking.1 ohm or what.
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You have to check the regulators by placing the black probe on the ground terminal of the regulator. Not all are referenced to ground.
Okay, yes they are at 12 volts and the other side has a 5 and 15 volt regulator. All are good until it protects.
The small resistors are 100k ohms. They should read consistently. They're connected between the gate ans source for each output.
Okay. Will replace all of them. The bigger ones are good? Or is my meter reading incorrect
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Yes you are correct as usual, all are within tolerance. I'm am somewhat color blind.
Can't figure why it is still protecting with all the output fets removed. Maybe the drive board is damaged again?
Can't figure why it is still protecting with all the output fets removed. Maybe the drive board is damaged again?
If the outputs blew in the amp the driver Ic's need to be replaced on the driver board ..
Remove the audio driver board and see if the amp still protects ..
When the outputs fail the 21844S'S fail as well
Remove the audio driver board and see if the amp still protects ..
When the outputs fail the 21844S'S fail as well
Can anyone tell me what the two 8 pin ic's are in the middle? Finally got other projects finished and back on mine. Thanks ahead of time.
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I don't know how you posted the photo but it's causing the photo to open in another window. It's better to use the 'go advanced' button below. When it opens in a new window, all of the text entered is wiped out and would have to be typed again.
U3 = TL072
U4 = LM211
U3 = TL072
U4 = LM211
Used my phone. Didn't know it would do that. Thank you again Perry.
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Well I have replaced everything, drivers and all fets. Powered up fine on initial test. Went to sound test and on power up it blew again. This is getting pricey. It's not on a power supply just battery bank. Battery voltage was 12.8..... Went back over everything for bridged solder joints, nothing.
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