Feb 10, 2021

Pong game RGB Mod

This console was made in Hong Kong and sold under many names like Grandstand, Soundic, Hanimex or as in my case MARK (Prelude Modell 64562).

My first attempt was to make a Composite video mod. This resulted in a horribly noisy video output. After some investigation I realized that it is easy to make an RGB mod for this console since it has separate signals for sync and the graphical elements. The signals are provide by the "AY-3-8610" chip in the cartridge. This is a single-chip-game that is called Supersportic or PC-501. It has 8 Pong style games and 2 that requires a rifle. I mapped the colors as close as possible to the original except for the background that I made black mostly because it was easier. But I think black is kind of cool. I may go back and add an option to make it green later. That would require a 3 input NOR gate...

Image captured from the console.

Below are some notes that may help if you are going to do a similar mod. I also removed the RF-modulator board and replace most of the capacitors. I accidentally blow up a 1N4148 diode before I realized that positive voltage from the external 9V PSU is ground for the circuits on the board! 

This is the result!

This Scart cable fit in the old RF output hole.
These are the connection point on the main PCB.

This is the schematic for my connections. The reason for using a 40106 schmitttrigger inverter was that it was what I had at hand. A regular inverter should do just fine. I had no OR gate chip so I used two schottky diodes.

Output amplifier and audio scaling.

Logic for color mapping.




  1. I cannot sleep for 3 nights. How to make background color? Where you take background signal if background chip on cartridge is not connected to any slot? Please help me! and thanks!

  2. When none of the other signals are active it is the background.