Broken Colecovisions.

[Captain Cozmos]

Before I break out the logic probe, soldering iron and oscilloscope I wanted to describe the issue and get your feed back..

I was testing three Colecovisions that I bought for parts.

One works, just dirty connectors, the second is clearly some dead vram but the third I have never encountered before.
 

It works until I get to the middle of the screen and then it wraps around to the left side

So I was testing mouse trap...middle wraps to the left.  I tried Centipede, the middle and wraps to the left.  Same with all the games.

First I was thinking last VRAM chip where the sprites usually sit but the patterns are fine.

 

So before I start screwing with the VDP and ram is it possible the controller ports or the 1K scratch Ram.

 

 

I also found a Gorf cart that are two EPROMS but so what, I can use them in another project as well as the PCB and shell.
They don't look like prototypes, just regular Gorf #1 and #2 1983 Coleco

 

Your thoughts....

CC

 

Edited February 4, 2023 by Captain Cozmos