Smash TV to MK board swap (copy protection?)

[mecha]

picked up a Smash TV board the other day on the cheap with graphical glitches (notably the text being a blocky mess in the test menu, among other anomalies in-game) and also happened to have an extra MK board without a sound board. figured it'd be a simple ROM swap, but then there's all the other little socketed chips that go with it I'm guessing.

I wasn't aware the Y-unit had such a protection scheme.

so after doing the exchange, the Smash TV transplant into the MK board generates a Custom Chip U99 error, and the MK transplant into the Smash TV board generates rom errors on every single rom and the game resets after the self-test ends. the Smash TV on MK runs, but has all kinds of graphical errors.

the MK on MK worked perfectly fine, I played it, no errors or glitches. so I'm guessing this is a protection scheme thing between the two boards.

so if I swapped every socketed "protection" chip out and this is happening, what do I do?

the Y-unit boards are of a different revision, based on the #'s I found silkscreened in. did I answer my own question or what?

as for the roms, the Smash TV is revision 5.0 and the MK is version 2.0 (kinda obscure now, right?)

help me channelmanic, you're my only hope.

 

[mecha]

I stand corrected, they have the same numbers above the revision.

the Smash TV board says Revision - while the MK says Revision B.

so a Y-unit's a Y-unit after all.

 

[tigerstyle]

It's interesting that its creating gfx artifacts.. Maybe the soundboards actually contain more than just the audio data?

edit: dumb theory, I just realised you can run mk without the soundboard and you dont have any gfx artifacts or resets at all.

 

[mecha]

yeah, I didn't even have the sound boards hooked up. I can't find any of my 50k pots for them. lol

 

[Magog]

yeah, I didn't even have the sound boards hooked up. I can't find any of my 50k pots for them. lol

Radioshack is where I got mine. Since then though a person here asked me to make them a solder-less soundpot spolution and they stopped carrying them in my area. But hey ya might get lucky.

 

[mrbill2084]

I had a smash tv leaving footprint like artifacts wherever the player went. I had a bad smash tv pcb and started replacing socketed chips in groups of 3.

I think it was one of the smaller/narrow 24(?) pin chips that had labels on them(not the eproms). Never nailed it down to which one of the 3..
you can probaby rob chips off nba jam,high impact and some mk1.

Some of the chips should be the same, but anything with a common number on them has to be game specific..

 

[mecha]

I have 2 MK boards with the same numbers on the smaller chips, different than Smash TV.

I replaced ALL of them between the Smash TV and MK boards I had. so they all had the same sequential numbers on them. I forgot to replace the biggest of the non-rom chips (the one on the battery/dipswitch side) at first... this is when Smash TV came up with a bad CPU and MK didn't boot at all. upon swapping that last chip, Smash TV stayed the same, and MK would boot but with errors on every rom. it was weird lol

then MK would crash after the POST. on the cab I had it in, it started clicking up the coin counter too, with a green rolling scrambled mess on the screen that looped over and over.

the Smash TV board must have had other issues in the past, cause some of the rams (I think?) had sockets on them.

wish a board repair guy could chime in about this. it'd help if I knew which chips did what.

 

[mrbill2084]

normally there are a ton of socketed chips on smash tv. here is a pic and a thread..
http://forums.arcade-museum.com/showthread.php?t=94577

http://farm3.static.flickr.com/2637/3685162687_37b5f7bae1_b.jpg

 

[mecha]

normally there are a ton of socketed chips on smash tv. here is a pic and a thread..
http://forums.arcade-museum.com/showthread.php?t=94577

http://farm3.static.flickr.com/2637/3685162687_37b5f7bae1_b.jpg

ah, the 4 small chips at the very top are socketed then.

well that puts to bed the myth of my board being a swap. I was always under the impression the dipswitch banks were blue on the older Williams Y-units. guess it doesn't really matter.

I guess I should put the 2 boards back the way they were and go back to the drawing board. so am I looking at a ram problem here? and which chips exactly are the rams, the long rows of them in the middle of the board or the 10 at the top? I'm not huge into this electronics stuff.. I just make things work somehow.

 

[DogP]

Did you verify the ROMs are the same physical chip? I know you're talking about MK, not MK2, but I had an MK2 board that apparently someone had tried to swap, but showed bad ROMs at all locations, and would sorta play, with scrambled graphics. There were several 0 ohm resistors to strap it for different types of ROMs, and apparently it was set for EPROMs, and mask ROMs were installed instead. Of course that shouldn't be the case if the MK and Smash TV chips are the same part though.

DogP

 

[mecha]

I went from slot to slot with them. I pulled one from one board, then the other, took the rom from board 2 to board 1, then the chip from board 1 to board 2. like that.

it's weird, both boards still had the labels on every rom still. lol

I'll have to compare the resistors though, see if they're banded the same way. I have another MK board I can try out, but that looks like it has mask roms (the kind that doesn't have windows?)

 

[mecha]

ok as far as I can tell the resistors are all the same. they're even soldered into the same holes.

both Smash TV and MK have EPROMs. the other MK board I have has mask ROMs. I'll attempt another switcheroo I guess. get to test the ol' supergun.

 

[mecha]

ok, here's where we're at now:

I moved Smash TV to MK #2, and MK #2's ICs to MK #1.

MK #2 on MK #1 works perfectly fine, no CPU error, which I guess deduces that the CPU error was a protection issue.

Smash TV on MK #2 is a catastrophic failure, it just rolls the rug pattern batshit crazy style, almost like there's no sync.

MK #1 on Smash TV still has the roms errors.

all 3 sets have the matching protection ICs that went with the romsets.

oh, and measuring the resistance across the resistors next to the rom sockets? .114 on Smash TV, .336 on MK #1 and .559 on MK #2.

DogP wins a prize... of no particular value.

so now what do I do?

 

[DogP]

You did swap ALL the socketed chips, correct? I don't remember those boards for sure, but I seem to remember there being a large PLCC chip, probably a CPLD or something. To get that chip out, you'd need a PLCC chip remover... but that chip may be custom to each game.

Is there a part number on the board that makes you certain that they're identical boards? There may be some minor differences, but largely based one board on the other.

About the resistors, they sound the same... what I remember was either resistors jumpered into different holes, or installed/not installed.

DogP

 

[mecha]

You did swap ALL the socketed chips, correct? I don't remember those boards for sure, but I seem to remember there being a large PLCC chip, probably a CPLD or something. To get that chip out, you'd need a PLCC chip remover... but that chip may be custom to each game.

Is there a part number on the board that makes you certain that they're identical boards? There may be some minor differences, but largely based one board on the other.

About the resistors, they sound the same... what I remember was either resistors jumpered into different holes, or installed/not installed.

DogP

no shit, the chip that's in the brown socket, that goes too? I always assumed that was some kind of co-processor or something, in which case, no, I did not swap those. I've yanked those before though, it depends on how "virgin" the socket is however.... lol I've done it with a small flathead before. I broke one of these sockets on my MK2 board, that's the one that caused my graphics to turn blocky, I had to wrap a ziptie around it to get the pins to make good contact again.

the resistors on the other hand are all in the same holes. I swapped every single one of the other chips, there's 8 in total. the one that's number 7, if you don't switch those over (which I have done on accident twice now) the game will not boot at all.

the largest chip in the corner, I forgot to change out, #8, and the game worked fine. I had the Smash TV one in the good MK that I got to work. another thing to note, is my good MK was a revision 3.0, and the one that only works on its original board is a 2.0. not sure if that makes a difference at all.

 

[DogP]

Yeah, I don't know for sure, but I wouldn't be surprised if that large chip was custom for each game. To pull it out without breaking the socket, the PLCC extractor tool is best... you can actually get them at Radio Shack: http://www.radioshack.com/product/index.jsp?productId=2062619 .

DogP

 

[mecha]

I PMed channelmanic about it, usually he gives me answers. I guess he got tired of me PMing him about things cause people generally NEVER reply to my threads unless I get someone else to make em active. oh well

there's zero information about it online too. I would think a Y-unit's a Y-unit, but whatever. the Smash TV and this Terminator 2 I was working on tonight both have gobs of solid white resistors on them. I'll bet you I could drop that Smash TV into that Terminator board and it work, cause they're older.

I've never seen a serial or part # affixed to those PLCC chips before though, I imagine they're all the same, but I'll give it a try.

 

[channelmanic]

Sorry,

Been busy with family, hunting, and house stuff and it won't get much better over the next 30 to 60 days.

I've never tried swapping those games around so I'm no help to ya.

RJ

 

[mecha]

Sorry,

Been busy with family, hunting, and house stuff and it won't get much better over the next 30 to 60 days.

I've never tried swapping those games around so I'm no help to ya.

RJ

well.. poop.

I might have to do the dissecting then.

 

[mecha]

PLCC chips are just what I thought they were: processors. they're the TI processors in fact.

they also made no difference in the situation. I guess one way I'll know is if I get a resistor off a MK board and drop it next to one of the Smash TV boards sockets and see if I get that rom to check out green will I know if that's truly the problem.

be a hell of a lot easier to change resistors than RAMs I suppose.

if I didn't mention already, the Smash TV on the 2nd MK board doesn't even boot to the POST screen, it just rolls like there's no sync. I think I said that though lol.

sounds to me like it's having difficulty picking up the rom contents, cause that was the board with the strongest of the rom socket resistors.

fucking strange, nonetheless. clever way to prevent people from loading different roms I suppose.