rockford fosgate BD1000

[mike49504]

Got another one of theese amps in for repair. Wondering if i can cut the mesha board here and repalce it with a small section of mesha board out of a scrap amp?

Since i dont have a mesha board long enough for this amp.

 

[0ldSch00lf00l]

Technically, you could use kapton tape and heat sink grease or Sil Pads if you were willing to make buss bars. If you are going through the trouble to cut a MESHA board, you may as well just de-solder the bad transistor(s).

 

[mike49504]

Still have problem with this amp after replacing the fets and drivers i get no gate signal and amp draws excessive current. I unsoldered the twisted wires and still draws excessive current.


With the power supply fets removed I have the following voltages on the SG3526N

1:11.34
2:6.32
3:10.67
4:11.11
5:11.37
6:6.82
7:6.62
8:6.82
9:10.86
10:8.58
11:6.82
12:11.37
13:6.82
14:13.20
15:6.82
16:6.82
17:13.21
18:11.40

 

[Perry Babin]

You could use the MEHSA insulator out of another identical amp but you have to cut it in a way that won't deform it. If you try using tin snips or something similar, the insulator will not remain perfectly flat,

Pin 15 should be at 0v.

 

[mike49504]

PIN 15 connects to pin3 of U7 (LM6361N) Theese are the voltages i have

1:2.29
2:3.23
3:6.83
4:2.28
5:0
6:3.28
7:4.28
8:2.28

Defective?

 

[Perry Babin]

I'm sorry, I should have said it should be connected to ground. Pin 15 is the ground pin for the 3526.

 

[mike49504]

I tracked it back to U7 then back up to the drivers for the power supply fets But no connection to ground terminal

 

[mike49504]

OK heres what i have on the LM339

1:6.84
2:6.84
3:13.21
4:6.90
5:8.41
6:9.05
7:11.40
8:6.38
9:6.38
10:11.40
12:6.82
13:6.84
14:6.84

 

[Perry Babin]

What is the DC voltage on these two points?

 

[mike49504]

The point next to the rail cap i have 0 volts. The point next to the tantalum cap i have 4.92 volts

 

[Perry Babin]

That's an electrolytic cap.

You have an open trace on the bottom of the board.

 

[mike49504]

Your right i found it and repaired it. Would that cause the excessive current draw?

 

[Perry Babin]

Yes. It could.

 

[mike49504]

OK i put the fets back in . Next problem is the amp wont power up .

Fets first leg is at 0 volts

 

[Perry Babin]

Post the voltage on the 3526 again.

 

[mike49504]

1:4.99
2:0
3:4.28
4:4.69
5:5.00
6:0
7:0
8:4.59
9:3.74
10:4.32
11:0
12:4.27
13:0
14:13.19
15:0
16:0
17:13.19
18:4.99

 

[Perry Babin]

Do you have a sawtooth waveform on pin 10?

Did you replace the 3526?

 

[mike49504]

I replaced the 3526 i have no sawtooh on pin 10 and i also have no square wave on the gates

 

[Perry Babin]

What was the manufacturer for the new 3526?

 

[mike49504]

Ill try putting the old 1 back in I forgot theese amps are touchy when putting in a new 3526