MTX Video Modification

You may have seen pictures of Peter Kretzschmar's extensively modified MTX512 on the Photos page. Peter has replaced the original 64k DRAMs with 1Mb of SRAM, of which 768Kb is useable and made extensive modification to the video output.

This computer also has an 80 Column board installed which outputs RGBS to a colour monitor. Peter was unhappy with the quality of the composite video output from the MTX VDP - the quality is degraded as it passes through the PAL video board, so he built a small board to generate R,G,B and S signals from the VDP component video outputs. He fitted a toggle switch on the end-plate to select which video output, VDP or 80 Column board, is selected for the monitor out connections.

The circuit diagram for Peter's custom video board is shown below :-