Meall Posted December 9, 2017 Share Posted December 9, 2017 (edited) I have a Vic 20 that displays a bunch of random characters on screen at boot up. Im trying to find the issue, but cant find it. I tested all socketed chips in a working one, and they look fine. Any idea? Edited December 9, 2017 by Meall Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted December 9, 2017 Share Posted December 9, 2017 I have no idea how the logic in a VIC-20 works so I cannot help, but I am very intrigued by the fact the characters appear to be up-side down and reversed... unless your picture needs to be rotated Quote Link to comment Share on other sites More sharing options...
Meall Posted December 9, 2017 Author Share Posted December 9, 2017 I have no idea how the logic in a VIC-20 works so I cannot help, but I am very intrigued by the fact the characters appear to be up-side down and reversed... unless your picture needs to be rotated They are not reversed on screen, that’s what happens when we take a picture of a monitor. Quote Link to comment Share on other sites More sharing options...
carlsson Posted December 9, 2017 Share Posted December 9, 2017 I believe this is a RAM failure. Sometimes if you insert a RAM expansion that is faulty, you can get similar effects on screen, in particular if you insert one that maps into the RAM/ROM block at $A000 or if it is the lower RAM block at $0400. As always, Ray Carlsen is a resource on troubleshooting. This is what he writes about the VIC-20 models: http://personalpages.tds.net/~rcarlsen/cbm/vic20/vic20.txt 1 Quote Link to comment Share on other sites More sharing options...
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