4300 no pre out on left rear

[Richs_Trains]

Hey guys, Well the 4300 I have been trying to bring back has but another issue. I am still waiting on the right channel P700 and the relay still takes 35 seconds before it kicks in, but the new discovery ... no pre amp out on the left channel rear. I have used every combination of connections and by process of elimination, there is nothing coming out on the left rear pre out. I have de-oxit everything at least once and most twice and cannot get a peep out of the left rear pre-out. I only have a DMM to test with, any help on how I can determine where I lose the signal would be most appreciated. Hoping to have the P-700 for the right channel sometime today. Thanks!!!! Rich

 

[petehall347]

you can use use your meter for signal tracing ..set it to 2v setting AC . then play music into the input .. meter should see voltage going up and down . if using a meter rather than a scope i find using music for the signal better than a constant signal so it doesn't get confused with normal voltages present . or abnormal ones for that matter ...
you could add a DC blocking cap to positive probe for better results .

 

[sKiZo]

Huh ... you still have signal to that amp, right?

I'd suspect a bad jack? Try jumping a cable to the leads going to that jack and see if you can get signal that way. I'd also trace the leads back and look for a loose connection, and maybe retouch the solder anyway as it should be easy enough to get to.

 

[bryans12v]

I would confirm signal from pe01 to pf01, then to pd01 before it reaches the amplifier module. You can confirm at the exit of Pd01 at JD01, JD02, JD03, JD04.

Confirm switches on PS01 are clean and working properly. With a flashlight, confirm that the contacts on the rear 2x4 switch aren't too corroded. This switch has been filthy on all my quads.

 

[rBuckner]

Of course don't cycle that 2 x 4 switch with the power on!!

 

[Richs_Trains]

Of course don't cycle that 2 x 4 switch with the power on!!

Thanks Randy, that's at least one thing I remember.

This unit developed more problems after the right channel P700 was installed and it is way beyond my capabilities. Thank you everyone for all your help, I have sent this one in to be repaired by Previd.