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mike49504 26th May 2011 02:18 AM

Rockford fosgate 4.6 X
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 26th May 2011 04:12 AM

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 26th May 2011 06:42 AM

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 26th May 2011 07:56 AM

Yes they are the same they match perfectly

Perry Babin 26th May 2011 11:27 AM

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

No input signal.

mike49504 26th May 2011 04:50 PM



Perry Babin 26th May 2011 09:19 PM

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 26th May 2011 11:58 PM

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

Perry Babin 27th May 2011 09:44 AM

Which leg of which transistor looked like that?

Can you post a photo of the distorted waveform?

mike49504 27th May 2011 06:50 PM

2 Attachment(s)
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

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