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

[mecha]

common question that I see on here is "how can you tell the difference between a Y-unit board and a T-unit board?" this mainly pertains to Mortal Kombat, which I'm sure anyone that remotely cares knows was made on both boardsets.

the only thing I haven't figured out yet is whether the sound boards are different or not. I've NEVER seen the sound boards for the Y/T-units ever labeled as such, and I figure they're just all the same.

but onto the pictures

the easiest way to decipher which is which is by the dipswitch banks. on the Y-unit, the dipswitch banks are right next to the CMOS battery. on the T-unit they're further away from the battery. there's other differences too, obviously between the different CPUs. the Y-unit has just a flat black plastic-looking package. the T-unit has a smaller surface mount chip.

that's the easy way to ID.

if you wanna get really fancy, Y-unit boards have Williams/Midway hardware genius "RAYMOND GAY"'s name silkscreened on the rightmost edge. my sample picture for the Y-unit also says Williams Electronics on it, I can't remember if they all say that or not, the Y-unit dates back to 1990 (technically 1989) when the WMS video gaming division was still using the Williams name which could lend itself to either being a board that was converted by someone else via ROM swap or maybe just cause there was excess boards laying around. MK1 was released a bit on the fringe... just about a year after they changed to Midway. though I may just very well be talking out my ass and never really noticed it on my vast collection of MK boards. lol

the T-unit has no particular characteristics that stick out to me. it's a very soulless boardset, and it was built very shitty compared to the Y-unit. it really at first glance will come off as a flimsy Y-unit.

just go based on the dipswitch bank placement, make your lives easier.

Y-unit:

T-unit:

 

[therealmogwai]

you my friend are an asset to this board! BIG love!!!

 

[Witchboard]

the only thing I haven't figured out yet is whether the sound boards are different or not. I've NEVER seen the sound boards for the Y/T-units ever labeled as such, and I figure they're just all the same.

They are different. If nobody else comes forward, I'll update your already useful topic with the sound board information and pics this evening.

 

[therealmogwai]

subscribed!!

 

[mecha]

They are different. If nobody else comes forward, I'll update your already useful topic with the sound board information and pics this evening.

is the board itself different, or are the roms different?

cause based on MAME, I think they run the same DAC and MIDI chips.

 

[Mitsurugi-w]

I just got a MK1 machine in November with no boardset. I had a Y-unit proto 9.0 pcb that I installed. The machine was wired for the T-unit. So instead of using rigged wiring with the y-unit I went ahead and bought a T-unit one also. Installed it last night. The sound seems better with the T-unit sound pcb but that might be because of the age of the y-unit. MK was manufactured for almost two years straight so it may just have old caps.

 

[Witchboard]

is the board itself different, or are the roms different?

The boards are physically different.

This is a Mortal Kombat II sound board for a T Unit.

This is a NBA JAM TE sound board that is the same as the Mortal Kombat sound board for a Y Unit.

 

[mecha]

that's an MK2 sound board. you can tell by the roms.

you can also tell it's not an MK1 sound board as it lacks the volume pot header.

my family's old MK1 was a 5.0 T-unit and it had the volume pot... and I know from MAME that there's no volume adjustment in the test mode either. heh

it used the same thing as the NBA Jam sound board.

EDIT: I read your post wrong, but the MK1 T-unit sound board is never labeled differently, it's just the same thing as an NBA Jam sound board in all reality. NBA Jam predated MK2, and ran the non-DCS sound board. when you get into older Williams-esque fringe releases, they did in fact run a different sound board. (my High Impact one looks entirely different from my MKs)

 

[Witchboard]

You've confused me. Do I need to change anything in my post, or pull the sound board out of my cabinet to take a pic of the MK1 Y Unit soundboard? It's exactly the same as the NBA Jam board I have posted, besides the EPROMs obviously.

The volume pot is connected to P5 on the Y Unit soundboard. You'll also note that the power inputs are different on each board.

 

[mecha]

ah, we were talking about whether or not the Y-unit MK1 and T-unit MK1 sound boards were different I thought? I'm pretty confused now too... lol

what I was saying is I think they're the same, cause I've never seen them for sale labeled as like "MK T-unit sound board" or "MK Y-unit sound board". I assumed they were the same cause NBA Jam, as a T-unit, runs the same sound board as the Y-unit MK1.

 

[Witchboard]

I would presume they use the same sound board. I would think the power wiring is the difference. I can post up pics of the wiring differences. I'll pull my MK1 sound board and post up a pic. You should consider pulling your High Impact just so we have a complete image record of the differences.

 

[mecha]

I would presume they use the same sound board. I would think the power wiring is the difference. I can post up pics of the wiring differences. I'll pull my MK1 sound board and post up a pic. You should consider pulling your High Impact just so we have a complete image record of the differences.

found this on ebay for now..... get a better pic later if I run across it. it's worth noting I packed all my excess JAMMA boards into a box last week however. lol

note the difference in the header placement, roms, misc. components.

also yeah, the Y-unit power harness was like 2 connectors... the T-unit mainboard (and MK2 sound board) were 1 long connector. I imagine they're just split on the sound board end for MK1. I sold off my NBA Jam TE awhile ago.... I forget how that thing was arranged. I think 1 solid plug and then 2 separate ones, then the volume pot.

 

[Mitsurugi-w]

I can put this y/t unit sound pcb debate to rest. Ok, they use essentially the same sound board. They run the same sound code. I swapped the Y-unit one onto the T-unit pcb and it worked fine so the answer is yes, you can swap y-unit and t-unit sound pcbs. See these pics:

Y-unit sound pcb:

T-unit sound pcb:

The major difference I see is the actual sound amp circuit. The Y-unit uses a HA13116 amp and the T-unit uses a MB3731. The circuitry around them is different. Notice the components under the metal "cage":

Y-unit:

T-unit:

 

[Mitsurugi-w]

Last pics of the amp differences:

Y-unit:

T-unit:

 

[mecha]

it probably has little to do with the boardset revisions as much as just updates to the sound board designs themselves you know? it would be interesting to compare to NBA Jam. I can't think of another release from between 1992-1993

 

[Witchboard]

I can put this y/t unit sound pcb debate to rest.

As far as the Mortal Kombat on the Y Unit and T Unit are concerned. It would seem the sound boards are more game proprietary than the main boards are.

 

[Mitsurugi-w]

it probably has little to do with the boardset revisions as much as just updates to the sound board designs themselves you know? it would be interesting to compare to NBA Jam. I can't think of another release from between 1992-1993

I compared the sound pcbs of both my NBA Jam and Jam TE and they are identical to the T-unit pics I posted above. Final revision of that particular sound system pcb? It changed considerably with the DCS sound system pcbs.

 

[Magog]

I can put the soundboard issue to rest completely for this.

Midway had 3 different soundboards (that I know of). ALL THREE WORK WITH Y-Unit MK's, T-Unit MK's and NBA JAM's. They are in essence the same. They all require a soundpot. The major differences were capacitors, amp differences, and the interconnectwiring(although the same essentially). THe interconnectwiring on 1 board comes as two separate plug pieces where as the 2 it is a singular plug(and the interconnect wiring is swappable).

Apart from slight hardware changes their functionality is THE SAME.

Y-Unit, or T-Unit if a soundboard works for one it will work on the other.



As a note I am basing the above on the 4 soundboards I personally own, and the T-Unit Rev 5 MK board I own, and the Rev4 Y-Unit board I own, as well as my own research on this subject.

 

[mecha]

excellent news.

though I digress, if you potentially dig a little deeper in the timeline closer to when the games were Williams releases, you might find some differences. key word: might.

I think structurally all the sound boards were the same between MK1Y and NBA Jam... my High Impact sound board... not so much.

then again, maybe it really doesn't make any difference either. they all require the 50k pot, I know this much.

 

[Magog]

I guess my statement completely to rest was incorrect.

As far as whether they work or not they do. I do think each of the boards are not game specific but more so time based, as in upgrades to the soundboard themselves (hardware wise).

and yep 50k ohm sound pot.