PIONEER SX-1000TW Unknown Capacitor

[moodyj2000]

I am working on a rebuild of my SX-1000tw. Most parts are straight forward but there is a capacitor on the bottom side that connects to the ground side of the filter capacitor. I have seen pictures of units without it but several with it. I can just order an axial replacement but was just curious about its purpose since I cannot find it on any of the diagrams. It is the 220mfd, 50V unit shown below.

 

[Watthour]

That's the main (65V) supply, right? The two (-) leads there are simply chassis ground, and the (-) of that "extra" cap is also connected there. The big question is what is tied to the (+) end of that 220/50 cap other than the 470Ω ½ watter. It looks like someone on the production line discovered a more convenient place to tie another cap to ground.