Hello, I am new to the forum looking for some advice. I am entirely new at repairing and diagnosing amplifier problems.
I have a Rockford Fosgate BD1000.1 that I bought with a couple JL subs from someone. When I turn the vehicle on the amp stays in protect mode at all times. I can hook up a different amp in the car and everything works, so I assume everything is wired correctly. It is a much lower power amp than the BD1000 if that matters.
Everything is currently wired with an 8 gauge wiring kit with a 50amp fuse, tied into a stock head unit with a line out converter. I have 1 JL Audio 10w3 (dual voice coil 2 ohm) wired in at what I think is a 4 ohm load. (positive (1) & negative (1) wired together then positive (2) & negative (2) wired to amp).
I have done some searching and it appears that U21 is a common failure that causes this type of problem, which would be a new experience for me. Aside from U21, the amp specs on crutchfield say a 4 gauge wiring kit is required along with a 100amp fuse. Could my 8ga kit and 50 amp fuse cause the protect mode?
Thanks for the help, sorry for the length...
I have a Rockford Fosgate BD1000.1 that I bought with a couple JL subs from someone. When I turn the vehicle on the amp stays in protect mode at all times. I can hook up a different amp in the car and everything works, so I assume everything is wired correctly. It is a much lower power amp than the BD1000 if that matters.
Everything is currently wired with an 8 gauge wiring kit with a 50amp fuse, tied into a stock head unit with a line out converter. I have 1 JL Audio 10w3 (dual voice coil 2 ohm) wired in at what I think is a 4 ohm load. (positive (1) & negative (1) wired together then positive (2) & negative (2) wired to amp).
I have done some searching and it appears that U21 is a common failure that causes this type of problem, which would be a new experience for me. Aside from U21, the amp specs on crutchfield say a 4 gauge wiring kit is required along with a 100amp fuse. Could my 8ga kit and 50 amp fuse cause the protect mode?
Thanks for the help, sorry for the length...
Doubtful these amps are pretty efficient and rugged.
Post all the DC voltage on all the pins of U21.
Post all the DC voltage on all the pins of U21.
If it only goes into protect with the engine running, the over-voltage protection may be engaging.
With the black meter probe on the ground terminal for the amp and the red probe alternately on the remote and B+ terminals (with the engine running) what DC voltage you read on those terminals?
With the black meter probe on the ground terminal for the amp and the red probe alternately on the remote and B+ terminals (with the engine running) what DC voltage you read on those terminals?
I'll have to wait until this evening after work to check the voltage. I should specify that the amp is in protect mode while the vehicle is running and when the vehicle is off but accessory is on. So I have never seen the amp powered on without the protect light on.
When checking the U21 pins, do I put my black probe on the amp for the ground also?
When checking the U21 pins, do I put my black probe on the amp for the ground also?
Ok here are the measurements assuming I did it correctly, black probe on amp ground, red probe on each node of U21, vehicle running. I'm not sure the correct order so imagine U21 is written at the top then numbered left to right:
U21
1. 5.02 2. -9.69
3. 7.82 4. -8.82
5. 8.35 6. 7.77
7. 9.66 8. -8.32
Ground to REM: 14.45
Ground to B+: 14.44
U21
1. 5.02 2. -9.69
3. 7.82 4. -8.82
5. 8.35 6. 7.77
7. 9.66 8. -8.32
Ground to REM: 14.45
Ground to B+: 14.44
The op-amp appears to be defective. With pin 5 below pin 6, pin 7 should be negative, not positive.
This is different from the most common failure of this IC where pin 6 is prevented from charging to greater than pin 5.
This is different from the most common failure of this IC where pin 6 is prevented from charging to greater than pin 5.
So U21 should be replaced. Is this a feasible job for someone with very limited soldering experience?
I have a soldering iron, but need a new tip for it. I have soldered some 14ga wire for some automotive wiring and that's about it. If I had to I could find someone with better soldering skills than myself.
From previous research where I saw you both provided input, I think I remove it with some Chipquik, clean it up, and then resolder?
From previous research where I saw you both provided input, I think I remove it with some Chipquik, clean it up, and then resolder?
Consequence of doing too many things at once, I think I made a mistake when matching my numbers to your schematic. This may change your diagnosis but maybe not the solution:
Pin 1: 5.02
Pin 2: -9.69
Pin 3: 7.82
Pin 4: -8.82
Pin 5: 8.35
Pin 6: 7.77
Pin 7: 9.66
Pin 8: -8.32
Pin 1: 5.02
Pin 2: -9.69
Pin 3: 7.82
Pin 4: -8.82
Pin 5: 8.35
Pin 6: 7.77
Pin 7: 9.66
Pin 8: -8.32
These definitely don't look right. The last set of numbers you posted would be more likely to be correct. Before you do any soldering, you need to take a close look at the pin configuration and re-check the voltages.
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