You probably have the older hardware based Megatouch like I have. Upgradeable to Megatouch 7. Which one are you running now? I have a Megatouch 4 Tournament PCB up for grabs, but not sure if that would be an upgrade for you, depends on what you have.
Yep, you got one of the first ones, runs on the PCB and uses a standard res. monitor. Theres not much you can upgrade it to beyond Megatouch 7. After that they moved on to the XL series. after that it has been software based using a PC hardware and a VGA monitor. Heres the manuals for the older games: