rockford 200ix
 

I have one I want to repair. It was driving 2 punch 18's @ 4 ohms bridged. Failure was likely the cause of driving hard into clipping over extended play. I have replaced all the caps in the power supply C13,C30,C12,C15,C22,C24,C16C28,C25 all with the appropriate caps.
many fets on the output side were visible damaged so I removed all pairs and replaced them with IRF 540 as called. When I power it up the led lights dimly and Q11 gets hot finally burned and popped the fuse. I need to get it idling before i can run a signal through it and see what I got signal wise.
When q11 is good i measure 28mohms on each fet q11,q6,q7,and q10
board version PC-0766-C
help me please !
Hugh

Connect only the ground and remote. What is the DC voltage on the 1st leg of each of the power supply FETs?

Place the black probe on the amp's ground terminal.

Q10 Q6 Q11 Q7
2.6mv 2.3mv -6.4 mv -2.7mv

What's the DC voltage on pins 10, 11 and 12 on the TL494 on the power supply driver board?

So youre thinking the op amp may be failing - causing a short in the supply bridge? What about the transitors coming off the TL494?

-The 200 ix was a strong amp in its day would be nice to have two mono bridged in one chassis with fan cooling to drive a pair of subs ....... or was that a power 1000? LOL!


Thanks,
Hugh

What's the DC voltage on pins 10, 11 and 12 on the TL494 on the power supply driver board?

pin 10 - 0v
pin 11 - 13.6v
pin 12 - 13.6v

Please don't use a hyphen as a separator. It can be confused for a negative sign.

The amp appears to be in protect mode. Post the DC voltage on all 16 pins.

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 1: 1.2mv
Pin 2: 4.66v
Pin 3: 54.9mv
Pin 4: 4.81v
Pin 5: 1.5v
Pin 6: 3.3v
Pin 7: 0v
Pin 8: 13.6v
Pin 9: .5mv
Pin 10: .5mv
Pin 11: 13.64v
Pin 12: 13.64v
Pin 13: 4.94v
Pin 14: 4.96v
Pin 15: 4.96v
Pin 16: .5mv

Pin 4 is being driven high which is shutting it down. Post the DC voltage on the LM339.

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: