Rockford 551S

[Hexhclass]

This amp had one 540/9540 shorted on one channel.I replace just these two mosfets and the drivers for test.That channel will produce low audio compare to the other channel.


Any suggestions where to start?

 

[Perry Babin]

Have you operated all pots (not the bias pots) and switches through their entire range while listening for audio to see if it the max level changed on either channel?

 

[Hexhclass]

Yes I did all that,I also used contact cleaner for the switch just to make sure.

 

[Perry Babin]

Set the crossover to full range for now.

Drive a signal into both channels and compare the signal levels on Ux04, pin 7. Are they the same?

 

[Hexhclass]

Went back ti this amp today.
I drive a signal in the amp,pin 1 and 7 of all op-amp are at the same level.

 

[Perry Babin]

I would suspect the input caps on the inverting/non-inverting inputs of the differential amplifier.

 

[Hexhclass]

6ohz. Same settings
On the speaker output terminals

 

[Hexhclass]

I would suspect the input caps on the inverting/non-inverting inputs of the differential amplifier.

Have a board location for these caps?

 

[Perry Babin]

See attached.

 

[Hexhclass]

I replace the caps both channel are at the same level now.






thanks