[rescue] COCO2 question and looking for a few chips
francois.dion at gmail.com
Wed Jul 8 20:42:07 CDT 2015
So, I started a RetroTech meet at $WORK. This is mostly about repairing and
maintaining older tech. We worked some on a COCO2. First issue, the
character set seems to be coming from the wrong bank. When it's powered on,
the characters are the graphical set, instead of saying stuff like BASIC
etc, we see graphic sprites. So it looks like there is a bit that's off
(high bank of the ASCII set). I've reset the ROMS and VDG and I've also
cleaned and lubed the pins on those with deoxit cleaner and deoxit lube. It
didn't help, unfortunately.
On top of that, the NTSC signal gets too weak after about 30 seconds and
the whole thing becomes unreadable. Cocos are not my expertise, but it
seems like I have a VDG chip going bad? Before I go and order some from
China and wait months for it to get here, I figured I'd ask here if anybody
has a spare one, or know a US source for them.
Also, a coworker is looking for a SID chip for his C64. I know they were
already hard to find some years back, but I told him I'd check around.
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