All PCB work is now complete on second Pioneer SX-838 receiver. Faceplate was pulled, control board had electrolytics replaces along with tantulum caps. All controls were cleaned well and lubed. The balance control causing distortion was the original issue the owner had with the receiver. The dial glass was not secured in the faceplate as the glue had deteriorated over the years so it was cleaned up and glued back in place. Knobs and faceplate were cleaned up look shiny again.
The amplifier was biased and had very little drift. All parts back together threw on the scope and fantastic results. The amp section is putting out 10-18wpc higher than factory spec before hard clipping even at the stressful 20kHz. When driven individually the channels push out 78 watts of power! Hooked the unit up for the start of break in and within three hours the soundstage opened up and that awesome Pioneer punchiness showed through. The receiver is back to its original glory and it is loud. Allowed the amp to run for several hours and normal heat dissipating.
Will run the amp for a few more long sessions to ensure quality and break in the new components. There are still a few lamps to replace and the service will be complete. Here is a few shots of the before and after of the control board. Not an easy board to get to.