rf 325.1 bad outputs? repairable?

I have a Rockford Fosgate 325.1 . Bench tested it today . Amp will power on and stay on . Hooked up a signal and checked speaker terminals with meter set on AC volts . The volts are very unstable - rapidly going up,down,etc.. Outputs are toast ? I found the FET`s on audio side of amp,part # FQA28N15 . Is this repair as simple as replacing those two FET`s ? Thanks

Were you using music or a signal generator as a source?   What makes you think that the 28N15s are toast?

music . However , I did hook up my RF 600.1 and 200.2 and they both had steady , well , steadier voltage readings - at least , I could have read them . What are you thinking could be wrong w/325 ? I just assumed outputs were gone . Outputs though is something i`ve always heard thrown around like it`s the only thing that could ever go bad . With cover off of amp I also noticed a pot that could be adjusted near the audio side . What is this ? The 325 will hopefully be on a single 10" kicker comp . This week I installed HU and RF punch components in the doors of my 93` Jeep Cherokee . Those speakers sound great . They are an older series only rated at 50w rms and seem to be doing great off of HU alone . I left the stock rears disconnected and couldnt be happier with RF`s at this point . Will that 10 be better sealed or ported with this amp ? Thanks all for helpin` out !

Later that day I reconnected the 600 to verify the 10 works . All is well w/sub . I thought of putting sub on the 325 , but if 325 is not right wont it burn up my sub ?

I have not adjusted anything . I went out and hooked up the 325 . I found stock speaker from Jeep and hooked it up high pass 200hz . Using the Technics receiver in the garage for rca out . The speaker did not play , only push cone forward and stop , switch polarity and then cone pull and stop . I measured terminals with multimeter . A+/A- = 40 DCV , B+/B- = 40 DCV , A+/B- = 40 DCV . Thanks

40 volts of DC = A boatload of DC voltage. Open the amp back up and with your meter set to the diode test function. It will be the only setting with a drawing, it is the symbol for a diode. Of course the amp should not be connected. You facing the transistor with the numbers so you can read them, place one meter lead on the center leg of the transistor and the other lead to the right leg, notice the reading. Duplicate for all of the outputs. They may all be the 28N15s but there may be some 36P15s. Let me know the readings on all transistors. That amp is a 1 channel amp. A positive and B positive are connected together inside the amp. So are the 2 negative terminals.

I am not familiar with that particular amplifier, but if it has 4 28Ns or 2 28Ns and 2 36Ps, we can get sound out of it today. There is probably only 2 shorted output transistors. We can cut the shorted ones off of the board. This will allow the amp to play again. It will not play long under any kind of a load. Reason for that is we are going to remove half of it's current capabilities by removing the shorted transistor. The only reason we are going to try to make it play is to determine if there is any more damage. Do not cut any parts off of the board until you let me know the readings you come up with. Then there will be one more set of readings to take so we can identify the shorted ones.

Lots of different settings on DMM . I used ohms . I know . . . you said diode right . Well , i`m just not seeing it . Seems like a nice enough meter to not have it . Q120 - 28n15 = .0 ohms Q123 - 28n15 = 11.5 ohms Q118 - 36p15 = 8.15 m ohms Q122 - 36p15 = 8.02 m ohms Was this any help to you ? Thanks again for your help tonight . You seem to have been around a few amps .

2 28`s and 2 36`s