> Can anyone give me any aditional information or manuals for these PCB's?
> The MegaPlay has about 9 sets of conectors which I have no idea what they are
> for!
> The MegaTech used a 2nd monitor, does the MegaPlay also use one?

Yes

> The MegaPlay board worked fine when I first tried it but after I swaped the cart
> order it stopped working! It powers on but doesnt boot the game, the screen just
> stays black.
> If I remove all carts I get to some sort of BIOS screen which says 'insert
> cart'... Any ideas?

You did turn it off before removing/inserting the carts the first time didnt you?
Clean the edge connectors with a non corrosive non grease cleaner.
Check the slots for dust etc...
Make sure the carts start in slot 1.
If that doesnt work, then you probably blew it up not having the -5v connected, it may use it to dump out the voltage when the systems powered down or something *shrug*, Im not sure exactly how they work...

> About the System Multi 32, can I run it with just one Jamma harness conected or
> do I need to connect both at once for it to work?

Just one will work.

> Also, what are those optical terminals and that weird port between the jamma
> harnesses for?

Controls, sound, led's and other custom cab bits.

Six...

System16 - The Arcade Museum