MK Y-unit/T-unit ID help for newbies :)

[Jon Hughes]

There are differences on the NBA sound board (meant for the T-unit) to the standard Mortal Kombat sound board. Firstly the power amp connected to the large aluminium heat sink is larger on the NBA board and is fixed with 2 bolts through the amp to the sink. The Mortal Kombat sound board has a smaller amp connected by a single bolt. Secondly some of the custom chips are directly soldered to the NBA sound board, whereas they're located in dual in line sockets on the original Mortal Kombat sound board. That's what I've noticed so far. To be honest you can swap the EPROMS from both boards over and it makes no difference - both work fine (with the correct ROM set) irrespective of what board you connect to. You will need a different power cables for the Y-unit & T-unit, one end is the same on both power cables. The other end, if memory serves, is 8 pin on the Y-unit and 9 pin on the T-unit.

 

[mecha]

There are differences on the NBA sound board (meant for the T-unit) to the standard Mortal Kombat sound board. Firstly the power amp connected to the large aluminium heat sink is larger on the NBA board and is fixed with 2 bolts through the amp to the sink. The Mortal Kombat sound board has a smaller amp connected by a single bolt. Secondly some of the custom chips are directly soldered to the NBA sound board, whereas they're located in dual in line sockets on the original Mortal Kombat sound board. That's what I've noticed so far. To be honest you can swap the EPROMS from both boards over and it makes no difference - both work fine (with the correct ROM set) irrespective of what board you connect to. You will need a different power cables for the Y-unit & T-unit, one end is the same on both power cables. The other end, if memory serves, is 8 pin on the Y-unit and 9 pin on the T-unit.

I actually acquired a MK T-unit board since I made this thread, came with the kit manual (I wonder if all the T-units were kits..?) and it had a note in the sound board section that there were 2 revisions of the sound board.

FWIW though, I borrowed a Y-unit one, complete with the Y-unit harness, and it worked without a hitch. you just have to offset the connector on the mainboard, I think you skip pin 1, I researched this against the pinouts on both the Y-unit and T-unit boards in the manuals. I might be thinking about the bigger connector that goes to the sound board too. haven't mucked with it for a week or so and I've been looking at all kinds of other hardware at work lately.

the only difference is the T-unit has an extra ground pin. if I so chose I could build my own power harness for it, I have all the .156 flat molex parts to do it.