PET 2001 Video Glitch Fix Board

This is a board which solves a problem sometimes seen on early model PETs, one of thin vertical lines appearing between some characters.

This can be seen most clearly as what appear to be spikes on top of one or both walls in 3D Monster Maze (https://tynemouth.itch.io/pet-3d-monster-maze) see photos for examples.

This fixes that issues by adding in a pixel clock synchronisation flip flop, so each pixel is samples in the middle and output. The output can only change ones per pixel clock, so the glitches are removed.

This replaces the 74LS08 chip in position E2 (next to the 6502). The original IC will need to be desoldered and a socket fitted (turned pin socket included). Desoldering on these boards is not for the faint hearted, it is very easy to lift tracks, so proceed with caution unless you are an experienced desolderer.

This is only suitable for the PET 2001 board, as shown in the photos. Not suitable for the 2001N or later.

If you have a PET ROM/RAM board installed, you will need to add an extra 40 pin IC socket into the stack to raise it sufficiently (not included).

This is for the assmebled unit only. No PET motherboards, PET ROM RAM boards or anything else is included.

More info on my blog:

http://blog.tynemouthsoftware.co.uk/2024/03/commodore-pet-2001-repair-part-3-video-glitch.html

Tynemouth PET 2001 Glitch Fix.pdf [875.77] KB