Need Help - Pioneer SX-9000 left channel distortion

[JHint]

Hi all, I’m hoping someone can shed some light on this Pioneer SX-9000 I’ve been fighting with:



When I first got it, testing showed that the left channel was very low and very distorted so I set about a full cleaning and rebuild.

After the total rebuild, the EXACT same problem persists - the amp board was in rough shape (mismatched outputs, disconnected wires, broken resistor all on the left side) but even the rebuild of all this did not help at all.

In testing the pre-out function to another amp, both channels were working (though the left was still noticeably low), so the main problem has to be in the amp/power boards, but both have had all capacitors and transistors updated with appropriate counterparts.

Do you have any thoughts what this could possibly be?

Thanks in advance -

 

[Mr Boochie]

Hi all, I’m hoping someone can shed some light on this Pioneer SX-9000 I’ve been fighting with:

In testing the pre-out function to another amp, both channels were working (though the left was still noticeably low), so the main problem has to be in the amp/power boards, but both have had all capacitors and transistors updated with appropriate counterparts.

All the output section transistors have been replaced, and the voltages test well.

Thanks!

 

[Bruno Primas]

With the power off and measuring across the VR 1& 2 trimmers, do you get between 0 - 50k ohms? On the VR 3&4 trimmers, do you get between 0 - 50 ohms? These fail regularly and the bias trimmers should be replaced even if working.