Trying to fix an Apple II+ : blue & orange colors "sparkle" & cap with only one connection

[eccofonic <eccofonic@charter.net>]

I pulled out my old Apple II after 6 or 7 years of neglect... it had
always been a little flakey, but when power was applied, it wouldn't
boot. Just a garbage screen. I cleaned the board and any dirty chip
contacts, and now it is booting fine.

Except...

Part One:

When I took the board out of it's case I noticed a 16v 10uf capacitor
*underneath* the board with one side soldered to power connector pins
1 & 2, which are both ground. The other side of the cap isn't
connected to anything???

I think I have the board revision after they removed the RAM size
select switches. It says "820-044-01"...

There is a 10uf cap labeled "C17" in the "Apple II Reference manual
addendum" schematic, but it is connected to pin 3.

Is the other end of this cap not supposed to be connected to anything,
or maybe "screwed down" to the die cast metal plate in the back
area... by the expansion card slots?

Part Two:

When the computer is turned on from a cold state... if it is booted
immediately to a graphic containing blue & orange colors... these
colors are purple and green instead.

Gradually, these areas start to "sparkle"... imagine hundreds of  dots
randomly flickering brighter...

And the blue and the orange colors "fade" in.

But the "sparkles" remain, mostly in the orange areas.

I read that Woz devised a circuit to add more color to the original
Apple II, so maybe this the culprit?

Thanks in advance for any info you can offer!