Rockford Fosgate bd15001 is drawing 20A

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I got this Rockford Fosgate bd15001 someone attempted to try to repair all transistors test good. I have unsoldered both pairs of red and black wires and tried to power up the amp which is still drawing 20A what should I look at next? Thanks!

 

[Perry Babin]

Connect only remote and ground and check the drive signal for each FET at their gates.

 

[amp it up]

Hi, do I need a scope for that? Or do you want the voltage. Thanks!

 

[Perry Babin]

You don't absolutely need a scope but that would be the best option. If you only have a multimeter, measure the DC voltage on both sides of all of the gate resistors and compare those voltages to the output of the SG3526 driver IC.

I don't know how much experience you have doing this. I'm assuming that you already measured the gate resistor for resistance and checked the PS FETs to see if any were shorted or leaking.

 

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Q6, Q5, Q7, Q2, Q18, Q23 and output B .995
Q11, Q10, Q9, Q22, Q24, Q4 and output A 9.60

 

[Perry Babin]

The IC looks to be defective but look around to see if you can find any strands of wire, solder bridges or other problems.

Double-check the driver transistors, especially the PNP drivers.

 

[amp it up]

Ok I will do Thanks Perry!

 

[amp it up]

Ok I will have to order some SG3526N’s Thanks again Perry!

 

[Perry Babin]

If you replace it, the resistor R34 will likely have to be changed. I use a 1k ohm. If you don't replace it, the IC may not produce any drive output.

 

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Ok Perry, I borrowed one out of another amp and now everything has 6.25V and I hooked up the positive wire and powered it on and it is still drawing 20A! What should I check next? Thanks!

 

[Perry Babin]

Are the red/black wires still disconnected?

Did you recheck the voltage (without B+) on every gate leg?

What are you using for a power supply?

After being on for a second or so, which FETs were getting hot?

 

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Yes The twisted red/black wires are still disconnected

Yes I checked voltages on every gate leg and it was 6.25v

I am using a pyramid PS-52KX for a power supply

Q22, Q24, Q4, Q2, Q18, Q23 are the FETs getting hot
Thanks!

 

[Perry Babin]

Pull the drivers Q29 and Q30. Do you still have high current draw?

Do you have a current limiter for the B+ line?

 

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Hi Perry I pulled Q29 and Q30 and I still have a current draw

Yes I have a 25W 3.9ohm resistor that I can put on the b+ line.
Thanks!

 

[Perry Babin]

Reinstall the drivers. Insert the limiter and power it up. Twist/push/pull the transformer being driven by the FETs that are heating up. Does the current draw change when you do that?

 

[amp it up]

OK I reinstalled the drivers, put on the limiter, twisted pushed and pulled on the transformer and it did not change the current draw.
Thanks!

 

[Perry Babin]

Does the transformer appear to have been overheated? Any peeling varnish on the windings?

 

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Hi, no it does not from what I can see. Thanks

 

[Perry Babin]

Did you check the rectifiers?

Is there a solder bridge across the pads for the wires that you desoldered?

Is there any current draw without remote?

 

[amp it up]

Perry, yes I did check the rectifiers and they test good.

No there is no Solder bridge across the pads for the wires that I desoldered.

There is no current draw with out the remote.

Thanks!