Hifonics BXI608 repair

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Hey all, I started working on this amp tonight and I could use a little input. I have tested the DFP50N06 on the audio side and they are all indeed shorted. There is no driver board and this is the first single channel amp I have worked on, actually I only have experience with JL Audio. I scanned Perry's dvd and can't find any schematics for the amp on it. I know im gonna have to replace the output fets and the power supply fets, which so far at least one is bad that I have noticed. This seems like a pretty basic amp, what else do I wanna look for before I throw her back together? Thanks in advance!
 
The DFP50n06's are the power supply fets for the amp.

I just repaired one of theese amps .

I had to replace all of the power supply fets ,gate resistors and the drivers for the power supply fets.

Thats where i would start. Check the gate resistors to see if they are within tolorance. Check the drivers for the power supply fets Pull the bad power supply fets out first before u test the drivers
 
Heres a diagram of what Im working with, since i see now IRFs at all:

This side is where the power and speaker outputs are

B1369 ------------- B1369
D2081 ------------- D2081
C5242A ------------ C5242A
C5242A ------------ "
C5242A ------------ "
C5242A ------------ "
C5242A ------------ "
HERF1004G -------- HERF1004G
HERF1004GA ------- HERF1004GA
DFP50N06 ---------- DFP50N06
DFP50N06 ----------- "
DFP50N06 ----------- "
DFP50N06 ----------- "

These are the semiconductors in order from the the power/speaker output side to the input and dials side at the bottom. The same transistors run down along each side of the board, directly across form each other. The C5242A are a lot larger than the dfp's or irf transistors, of which there are none of the latter.
 
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Yes . Those are the other half of the outputs. It has to have enough outputs to handle the power dissipation and current flow produced by it's lowest impedance load. All else being equal, amps that are designed to handle 1 ohm loads will have to use more components than an amp designed to handle only 2 ohm (or higher) loads.

Did the outputs fail also?
 
If I'm not mistaken, the transistors in the yellow rectangle are the drivers. Check the signal on the first leg of each driver transistor. The right (falling) edge of the drive waveform should be perfectly vertical down to within ~1v of ground. Compare it to the waveform on pins 9 and 10 of the TL494/TL594/ka7500 driver IC. In the attached photo, the top waveform shows a good drive signal. The bottom waveform shows a bad drive signal produced due to a defective driver transistor.

Also check the gate resistors for each of the power supply FETs.
 

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