Rockford fosgate Bd1500.1

[mike49504]

I recieved yet another one of theese amps in for reapir.

The power supply fets were shorted so i replaced them with IRF3205's .
Also replaced the 10 ohm gate resistors. The drivers are also new.

I unsoldered the red/black twisted wires from the board on 1 side .

When trying to power it up as soon as i add remote voltage it draws excessive current.

Any ideas what this might be?

[FireII]

Shorted outputs?

[mike49504]

The problem is in the power supply Once you unsolder the red and black wires it disengauges the output section.

[FireII]

I see I don't know much about rockford repairs.

Did the rectifiers survive? Possible shorted cap? Just throwin things out there as I have another budweiser =)

[Perry Babin]

Power it up without B+ connected (only remote and ground). Does the gate drive waveform look OK?

[mike49504]

Perry,

is it 10 us 5 volts div?

[mike49504]

Im gonna have to go buy a new probe first since the one i have is not reading .

So i will go get a probe and check to see if i have good square waves on the gates and let you know

[Perry Babin]

10uS and 5v would be a good starting point.

[mike49504]

there is 16 Power supply fets in this amp.

On 4 of them in the first bank of fets i get a nice square wave. The last 2 in that set i get a wavy line.

Next bank of fets i dont get a nice square wave on that bank.

Where would i go from here?

[Perry Babin]

If the waveform isn't going to ground, the PNP drivers are defective. Check the gate drive signal on the outputs of the 3526, on the bases of all drivers and on the emitters of all drivers to see which don't have a square wave signal.