Archived from groups: rec.games.video.classic (
More info?)
> It's possible the color pot may need to be tweaked a bit. I'd
suggest
> you go to
www.atariage.com and look for the 7800 forum to see if
> anyone posted a similiar question or you can post your question
there.
I've fixed it. It was indeed a bad connection either with the colour
pot or a short circuit on the motherboard around the colour pot. It
seems that over the years the gentle flexing the 7800 motherboard
receives when cartridges are inserted and removed can cause this sort
of problem on the motherboard. I re-heated all the contacts on the
motherboard with a soldering iron and turned the pot a few times with a
screwdriver to help remove any internal oxidization. It works fine
now.
You could tell it was a bad contact problem because if you pressed on
the top of the RF shielding with medium pressure while the system was
turned on, the colour would intermittently go to black and white and
back (with yellow remaining as the only constant).
Thanks for all of your suggestions.
PS: my usenet searching indicated other people have had this problem
too (with 2600 games playing in B&W). So it's nice to know it's a
relatively easy fix.