[Coco] Color blind coco1 :(

[Luis Antoniosi (CoCoDemus)]

Hi guys,

I was doing a composite board (using the vdg 6847 scheme) for the mc1372 on
my coco1. It was working but I accidentaly touched a resistor (mc1372 pin
14) connected to +5V to the RF metal can. It reset and since them the
colors are all screwed.

Instead of green text I have a brown/pink and even the green pmode 3 seems
brown. Even the s-video driver gets brownish colors.

-I replaced the mc1372 and the mc6847 with no avail same result.
-I checked the color lines from 6847 and they are fine.
-Replaced the 104 cap on the chroma bias between 6847 and 1372 same thing.
-Turning the color burst trimmer has no effect. I even replaced the xtal
and the colors are the same.

The computer works fine, only the colors are messed up. I suspect now the
caps in the clock line but I'm not sure anymore. Do you guys have any clue
on what should I check ?

Notice that this computer never had the PMODE4 artifact colors (red/blue)
correct. They were always green/pink or cyan/crimson. But now the colors
are screwed up this freaking computer show these colors as red/blue! DAMN!

This is a F board coco1. There is the "fix-in-a-noodle" over the mc1372
that goes exactly on vdg clock line. But my fix seems to be different. I
tried disconnecting this "bridge" again no difference.

see the fix I have (i removed the noodle for the photo):

pic.twitter.com/wME0rAp4Yp <http://t.co/wME0rAp4Yp>


Any help is appreciated,

Thxs,

-- 
Long live the CoCo