Rockford fosgate 4.6 X

[mike49504]

i replaced the outputs and emitter resistor in the right rear channel.

when i power it up and test for output the left rear channel has no output and the right rear channel has very low distorted output. I tryed cleaning the gain pots and swapped the crossover cards still no change..

Any ideas?

[seankane]

Wondering if this is the same board as the 4600X? Can you post a pic of the board? Do you have good supply voltage on all of the op-amps pins 4 and 8? Have you checked for an open or out of tolerance SMD resistor? Have you checked to see if the rail caps are leaking? Have you checked to see if the RCA connections are loose or came un-crimped? Have you checked for loose or cold solder joints on the cross-over card slots?

[Perry Babin]

Drive a signal into the LF and RR channels. Compare the signal levels on pin 1 of U102 and pin 7 of U302. Are they they same?

Set all crossovers and gains the same.

[mike49504]

Yes they are the same they match perfectly

[Perry Babin]

What's the DC voltage on the emitter of Q105 and Q405?

No input signal.

[mike49504]

Q105:-9.58

Q405:-9.60

[Perry Babin]

Did you touch the scope probe to the output transistors of the dead channels to confirm that there is no audio on any of the outputs?

[mike49504]

I placed probe on output transistors and the sine wave is flat on the top side it looks like a square wave

[Perry Babin]

Which leg of which transistor looked like that?

Can you post a photo of the distorted waveform?

[mike49504]

Scope set to .5 volts/div and 2 ms. and 100hz sine wave

First pic is the middle pin on the 9540 and 2nd pic is middle pin on 540 both rear channels have the same wave on the outputs