Rockford Fosgate T20001BD wont power up

[amp it up]

HI I have a Rockford Fosgate T20001BD that wont power up at all it doesn't draw any current at all. I don't have a scope but I do have a DMM! Where should I start? THANKS!!

[Perry Babin]

Start by posting the DC voltage on all of the terminals of the SG3526. Copy and paste the following into your reply.


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 15:
Pin 16:
Pin 17:
Pin 18:

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Heay Perry I knew you would be the first to answer Thanks!!

Pin 1: .42
Pin 2: .137
Pin 3: .045
Pin 4: .006
Pin 5: .700
Pin 6: .000
Pin 7: .000
Pin 8: .006
Pin 9: 3.58
Pin 10: 1.921
Pin 11: .001
Pin 12: .667
Pin 13: .001
Pin 14: 10.36
Pin 15: .000
Pin 16: .001
Pin 17: 13.34
Pin 18: 4.98

[Perry Babin]

It appears that you don't have remote voltage. If you have 12v on the remote terminal, post the DC voltage on all pins of U1.

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Pin 1: .005
Pin 2: .005
Pin 3: 13.94
Pin 4: 4.59
Pin 5: .258
Pin 6: .256
Pin 7: 8.67
Pin 8: .196
Pin 9: .138
Pin 10: .000
Pin 11: .056
Pin 12: .000
Pin 13: -.287
Pin 14: .001

[Perry Babin]

Pins 5 and 6 should be connected to pin 18 of the 3526. See if you can find the break in the circuit.

[amp it up]

Perry it looks like I have a 1R0 resistor that's broke. I don't have no 1R0's what can I put in its place to test The amp?

[Perry Babin]

If you don't have a 1 ohm surface mount, you can use a leaded resistor.

Check C8 and C9 before replacing it. One may be shorted.

[amp it up]

OK I went and got a 1 ohm resistor and installed it and the amp powered up and played fine but r35 and r36 gets real hot You cant touch them and the amp was only on 2 or 3 min. what should I check now? THANKS Perry for all your help!!

[Perry Babin]

That's normal. Those resistors are connected across the rails. They ensure that the rail caps drain quickly after the amp is switched off (some of the old BD amps would retain a dangerous charge for weeks).