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

[BLuRry <brendan.robert@gmail.com>]

On Sunday, January 20, 2013 1:23:31 PM UTC-6, eccofonic wrote:
> 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!

Yes, there was a color mod that II users had to install on the board -- it could have been improperly installed though.  Is it a Rev 0 board?  If so you might want to find the installer instructions and verify the parts are correctly wired and not failing.  Or replace the capacitors in question.

-B