Acclaim 51555 PCB compatibility

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lidnariq
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Re: Acclaim 51555 PCB compatibility

Post by lidnariq »

genepensive wrote:53361-2: pin Q0 (Eprom 13) -> cart pins 34 (CIC toPak) & 30 (PPU D0)
[...]
53361-2: CIC pin 2 -> cart pins 34 (CIC toPak) & 30 (PPU D0)
There's no way that's right: that has to have been shorted together when it shouldn't,
genepensive
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Re: Acclaim 51555 PCB compatibility

Post by genepensive »

lidnariq wrote:There's no way that's right: that has to have been shorted together when it shouldn't,
You were right. I checked against one of the other boards I have and it looks like I shorted a trace under the socket (the solder wandered).

After fixing that, I'm still seeing the following from the CHR rom using Megaman 3 (the EPROMs work right on a 51555-2 board):

http://imgur.com/a/ULfdN

Are MC-ACC pin-compatible with EPROMs?

I have a few of these carts and there's no way to really tell the difference from the label - they all look the same. Some are 51555-2 (MMC3B) and others are MC-ACC boards.

Thanks again for your help.
lidnariq
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Re: Acclaim 51555 PCB compatibility

Post by lidnariq »

I am reasonably confident that all the resist-lacking Acclaim PCBs just used standard JEDEC pinouts, and that that is the same as UVEPROM pinout for 1 and 2 Mibit ROMs...

But then I don't know what GameMachineJames's comment was about. Where in which Mega Man is that? It shouldn't be too hard to figure out what bank is being displayed vs which one was requested, and after we have that information it'll hopefully shed light on what's wrong.

On some level, given the picture, it has to be "the upper address lines are wrong" but that's so vague as to be useless.
genepensive
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Re: Acclaim 51555 PCB compatibility

Post by genepensive »

lidnariq wrote:Where in which Mega Man is that? It shouldn't be too hard to figure out what bank is being displayed vs which one was requested, and after we have that information it'll hopefully shed light on what's wrong.
This is Mega Man 3 (NA) using the Akklaim (Acclaim) MC-ACC MMC3 clone [53361-2 board] from a Roger Clemens MVP donor. The two other screen shots are from Shadow Man's intro and from the first part of the level.

The EPROMs are 27c020 UV EPROMs. The CHR ROM is doubled up to fit onto the EPROM (Mega Man 3's CHR is 128Kb). PRG is 256Kb. They work perfectly fine on another Roger Clemens board with a proper MMC3B on it.

http://imgur.com/a/trzm6 (works properly, I have this board with sockets installed for testing)

http://imgur.com/a/4bs9h (errors in CHR) <-- this is the board I'm working with. Same donor (in name only), same EPROMs.

Video of the CHR errors: http://sendvid.com/r67me113 - as you can see, it seems like it can read the first portion of the ROMs (notice how everything in the level select looks right), but maybe it can't switch banks properly? I'm not sure. There's not a lot of info on how to rewire MC-ACC boards.

Thanks for your help.

edit: Just a thought.. perhaps CHR only needs to fill half of the EPROM, and the other half needs to be zero-filled? (Something about it being pulled "high" or "low"?)
lidnariq
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Re: Acclaim 51555 PCB compatibility

Post by lidnariq »

genepensive wrote:Video of the CHR errors: http://sendvid.com/r67me113 - as you can see, it seems like it can read the first portion of the ROMs (notice how everything in the level select looks right), but maybe it can't switch banks properly? I'm not sure. There's not a lot of info on how to rewire MC-ACC boards.
So somehow it's selecting the wrong bank.
On the first screen:
* The boss selector is tiles in banks $7C-$7F, all tiles. Additionally sprites from bank $34 are used to fill in white-person-skin-tone bits. All display correctly.
* When Shadow Man is supposed to be striking a pose, his sprite tiles are supposed to be bank $2F, and the sprites are tile indices $F8 through $FB. Instead we see the smirk portion of a face, which comes from bank ... $3F.

On the next screen:
* All the background tiles are supposed to be from banks $5C-$5E, indices $0C-$0F at the top line; $1C-$1F and $2C-$2F in the middle; $3C-$3F above the platform, and instead we see the letters that are in bank ... $7C-$7E.
* Mega Man's sprites are in bank $00, and they display correctly.

In the first case, the A14 line is high when it shouldn't be; in the second case, the A15 line is high when it shouldn't be. And ... that's all I can tell. I don't know whether it's a wiring problem (although GameMachineJames implied it is) or a logic problem or whether the wiring problem is between the ROM and PPU, PPU and mapper, or CPU and mapper. But if I had to take a guess, I'd look closely for a short between CHR A14 and A15.
edit: Just a thought.. perhaps CHR only needs to fill half of the EPROM, and the other half needs to be zero-filled? (Something about it being pulled "high" or "low"?)
I'm confident it's not that...
genepensive
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Re: Acclaim 51555 PCB compatibility

Post by genepensive »

lidnariq wrote:But if I had to take a guess, I'd look closely for a short between CHR A14 and A15.
Wow. I'm blown away. Good call.

There was a tiny solder blob under A15 that was shorting to A14.

THANK YOU! It works perfectly now.
lidnariq
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Re: Acclaim 51555 PCB compatibility

Post by lidnariq »

By the way, we have an old kinda-dubious pinout of the MC-ACC here ... but
genepensive wrote:The other thing I noticed is that anything using the ACCLAIM-MC-ACC maxes out at 384Kb combined
There is the possibility, if the pinout is correct, that pin #39 on the MC-ACC might be PRG A18. At least, in terms of spacing it's right.

No idea what the disconnected pins 6-8 are. They might be an enable for RAM, though.

If you feel up to it, you could consider this a request for verifying the pinout that old post...
genepensive
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Re: Acclaim 51555 PCB compatibility

Post by genepensive »

lidnariq wrote:If you feel up to it, you could consider this a request for verifying the pinout that old post...
I have one more MC-ACC board left, I'll give it a shot.

I was able to get Mega Man 3 running on my dev/test (socketed) board, I'll run the MMC test suite on it this weekend.

Thanks again for your help!
brucebrown50
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Re: Acclaim 51555 PCB compatibility

Post by brucebrown50 »

Question for genepensive

So, in the end, what wiring did you have success with for each type of acclaim board (51555-2 and 53361-2)? Is it just standard TLROM wiring or did you have to make additional changes?
genepensive
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Re: Acclaim 51555 PCB compatibility

Post by genepensive »

brucebrown50 wrote:Question for genepensive

So, in the end, what wiring did you have success with for each type of acclaim board (51555-2 and 53361-2)? Is it just standard TLROM wiring or did you have to make additional changes?
I had success with both. There was no re-wiring required, just drop the EPROMs in, IIRC. I'll verify for you this weekend.

The biggest issue was that the pins are so easily shorted..
brucebrown50
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Re: Acclaim 51555 PCB compatibility

Post by brucebrown50 »

Yeah that actually worked! I got a TLROM running on a 53361-2 (w/40 pin mmc3 clone). No bending pins, no wires. Just dropped in two 4mbit chips.

The PRG socket wiring didn't quite match a normal TLROM board PRG socket. I started to go through tracing every wire, but then I figured why waste the time I could always take the chip out if that didn't work.

Thanks for the help!
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Yolt1
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Re: Acclaim 51555 PCB compatibility

Post by Yolt1 »

Hello Guys,

Here I am, a little (very) late to the party.

I recently stumbled upon this thread and wanted to verify by myself.
In PAL region we did not have any of those ACCLAIM games with the MC-ACC "mmc3-clone" chip. All of those game came on normal TL-ROM boards.
As you can imagine - here in Europe - NTSC cartirges are not easy to come by. But fortunately I found one almost directly what I needed. It was the only one of the short listing of MC-ACC Game and it was RollerBlade Racer with label in poor esthetic condition (I hate tearing apart good-looking games) + it was really cheap... judge by yourself :
20240307_134307 (Grand).jpg
Here is the inside with all component out :
20240307_091439 (Grand).jpg
I soldered sockets and tried everything. It worked :-)

Having a MMC3 test cart was not my intention but I wanted to check the statement made some years ago by Lidnariq and if possible give a possitive feedback.
lidnariq wrote: Fri Apr 21, 2017 10:17 pm By the way, we have an old kinda-dubious pinout of the MC-ACC here ... but
genepensive wrote:The other thing I noticed is that anything using the ACCLAIM-MC-ACC maxes out at 384Kb combined
There is the possibility, if the pinout is correct, that pin #39 on the MC-ACC might be PRG A18. At least, in terms of spacing it's right.

No idea what the disconnected pins 6-8 are. They might be an enable for RAM, though.

If you feel up to it, you could consider this a request for verifying the pinout that old post...
So, after rechecking the mapper, I can confirm that the "kinda-dubious" pinout is correct ^_^ and most importantly your statement is absolutely right!
I gave it a try and rewired pin31 of the PRG Eprom (originally tied to Vcc) by cutting the trace a addind a cable directly on pin39 of the mapper (which was originally NC). See pics :
20240307_134901 (Grand).jpg
The biggest problem was to find a TL-ROM game, or a NoRAM-MMC3 game if you want, with a 512k PRG... quite rare
But, there is the "improved MegaMan 3" patch made by Kuja Killer, found here , that makes the game CHR=256k and PRG=512k a perfect fit for our test... And here is the result :
20240307_154150 (Grand).jpg
20240307_135805 (Grand).jpg
So, I am happy to say that MC-ACC is a great test-cart solution* for "every" TL-ROM games since the chip accepts PRG-ROM-A18 signal as the original MMC3 did.

Cheers


* You already know but just to insist on one more reason : it has 1-on-1 pinouts for both CHR and PRG in comparaison to the EPROMs we use.
lidnariq
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Re: Acclaim 51555 PCB compatibility

Post by lidnariq »

Thank you for coming back to this!

Since you've got it socketed, can you check if there are body diodes on pins 6-8? Using a diode tester, check for a diode from ground to pin 6-8, and from pin 6-8 to +5v.
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Yolt1
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Re: Acclaim 51555 PCB compatibility

Post by Yolt1 »

Hey there,

I remember you suspected pins 6 to 8 beeing for an hypothetic RAM management.
OK I'll gladly do that and check those out.
But don't get me wrong I am just an old-school video game hobbyist :-) My knowledge in electronics are (very) limited.
So, just to get this straight and make sure I can be efficient to provide valid date, could you confirm what I need to do?

1. I'll take out the MC-AC mapper.
2. I'll set my multimeter to "diode" mode
3. I'll put the positive lead to the +5V (pin40) and the negative to pinX (6, 7 or 8), write down the result
4. I'll put the positive lead to pinX (6, 7 or 8) and the negative to GROUND (pin1), write down the result
Am I getting this right?

Or maybe diode testing is done like this (sorry for the rough sketch) :
20240308_123721.jpg
The idea here is to have pinX (6, 7 or 8) tied to +5V and GROUND and then take measure with the multimeter with the leads on +5V and GROUND.


Please confirm and I'll try it as soon as I get back home from work.
lidnariq
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Re: Acclaim 51555 PCB compatibility

Post by lidnariq »

Yolt1 wrote: Fri Mar 08, 2024 4:38 am 1. I'll take out the MC-AC mapper.
2. I'll set my multimeter to "diode" mode
3. I'll put the positive lead to the +5V (pin40) and the negative to pinX (6, 7 or 8), write down the result
4. I'll put the positive lead to pinX (6, 7 or 8) and the negative to GROUND (pin1), write down the result
Am I getting this right?
Probes exactly reversed (positive lead to ground, negative lead to pinX; negative lead to +5V, positive lead to pinX) - you're checking for the diodes that protect the chip against static electricity.

Actually, you don't need to take it out of the socket either, since your PCB photo showed that pins 6-8 aren't connected to anything in the PCB.
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