anyone ever seen a snes sfx-multichecker?

I've been collecting dev eprom game boards for a few years and thought I had seen most of the snes ones. Recently I was offered some sfx-multichecker boards which I had never seen and I immediately paid too much money for them.

I found them interesting because they're the same style as the powerfest carts (but obviously aren't the same circuit boards or even event carts). What the cart in the picture is standing on is what plugs into the snes. In a sense it's like a supersized version of the famicom protos in ram adapters as far as the physical setup.




What I was told is that these were used earlier on in snes development
before the just circuit board carts came along, but I feel the "multichecker" part of the name may imply some further purpose. I haven't had time to trace any of the circuit yet to see what things do and I didn't get any of the paperwork (which I would love to get a copy of if it happens to be floating around).

Just thought I'd throw this out and see if anyone knew any more about these or about this style cart.

 

I've seen them before, but not up close so can't say anything without knowing the parts. What are the two DIP ICs? One a 6264 or 62256 and the other DSP or a PLA? I'd guess since there's 8 ROMs, the address decoder is a 74138 and the second DIP chip is a PLA that decodes SRAM and limits it, maybe ROM too. Since the ROM sockets are 32-pin, it either supports 32M or 64M so I suppose it supports HiROM too via a switch setting to emulate most boards. Personally I don't think this is from too early in the SFC's life, probably like 1994. Look at the date codes of the chips, they'll at least indicate when they were shipped.

 

If you look closely, you can see one of these used in the Donkey Kong Country Exposed Video

This is from 1994, so it probably was for betatesting at Nintendo throughout the whole lifespan of the SNES.

I've never heard or seen one of these outside Nintendo, though.
Maybe they were expensive and most 3rd party developers rather used backup units or the cheaper normal protocarts.

[edit]
Actually, the carts seen in the above video at around 4:00 look different.
I assume their purpose is similar, though.

 

I have 2 styles myself now (both sfx-multicheckers but with different numbers afterward). I think the second style looks like the one in the video. Thanks so much for that info. I would have never found that video.

I'd be happy to share some more pictures probably this weekend. These came from outside Nintendo. My source said that they were used very early before they had any other dev hardware. Maybe they bought them early on and they found that they were too expensive to use often. I don't think my source will know...

Edit: The latest date on the chips for the sfx-multichecker-01 s I have is 9102. The earliest is mid 90. The multichecker-2021 I have is all mid 93 (and it looks like the one in the donkey kong video).

 

Very interesting indeed, I'm looking forward to these pictures!

A wild guess: The name Multichecker-2021 may imply that this model is capable of both lorom and hirom modes. (internally refered to as mode 20/mode 21)
That'd mean the earlier ones only support lorom.
IIRC, the first hirom games didn't start to appear before 1993, anyway.

 

The 2021 also has those two plugs on the side that look like they're for debug cables of some sort.

 

I've got 4 of those carts with top shell to close them.
Got a 2021, another with just "MULTI CHECKER" on the label. PCBs are the same but chips have different serial numbers. Not knowing about this thread I made one few minutes ago -here-.

My carts come from Capcom.

 

Yea, all of these are from the same eBay seller camnma5pt0 (I assume, since she got ahold of 10 of them and just sold them on eBay, at which point I could find absolutely nothing anywhere on them =P).

 

no, mine are not from that seller. I also paid more... Nicola, you don't want to sell a lid or two do you?

Also Nicola, from your pictures, I only see sfx multichecker-01's. The 2021 on your lid refers to a different circuit board--the sfx-multichecker-2021. I have one of these. That's the lid you should sell me since it doesn't match your board...

Slightly less blurry than Nicola's pics:



I'll post the 2021 when I get one that's not all blurry!

 

Man, I wish I saw those before. If anybody wants to sell em, please PM me

 

The 2 lids that I have are different: the one with just "SHVC MULTI CHECKER" has a small hole on the top. I'm going to take some good quality pictures soon.

 

Why is everyone going nuts over these? They're just EPROM carts... If it were a RAM cart with SCSI port like the cases suggest exist, that would be a little more interesting (even then not TERRIBLY interesting since it can't be a debugging system or anything, just a very expensive poor copier).

The better picture confirms almost everything I guessed. I can't see whether or not it supports 8M ROMs since the socket blocks the silk screen. It looks like it supports 8x2M ROMs for 16M or 8x4M for maximum 32M. There's not a big chance the PLA can adapt the cart for HiROM since that takes 7/8 PLA outputs, and just barely could implement SRAM decoding and limiting. I doubt the engineer was that clever though, so like d4s said, that must be why the 2021 version was released, perhaps that one supports 8x8M ROMs and has a discrete multiplexer like a 74157 or two to handle HiROM and/or a better logic device.

If you want to fully understand the circuit (I really wouldn't bother), the only way is to learn the equations of the PLA, which can be read like a ROM if you switch two signals, then be processed back into it's sum of products.

What is the RAM used? I assume 6264 = 64Kbit, this would mean maybe there is one option of SRAM limiting down to 16Kbit, and perhaps another option to enable/disable the RAM. The last two switches must be for shifting the high address lines so the decoder works for both 2M/4M ROMs, and the last maybe for mirroring or 8M decoding if indicated by the silkscreen.

 

I think it's more about collector's interest than homebrewer/developer's.

 

I collect this kind of stuff and it's something that was new to me. Since I collect dev carts, you'll probably see me go nuts over them often... I wasn't sure whether this was really for the "dev" forum or not, but it looked like similar topics were here.

 

I understand collecting, but I don't see how an EPROM cart has any substantial collector's value if there isn't a game on it, in that case it has no use except for development or very convoluted piracy. I know some people collect only for provenance, but without actual functionality there's no intrinsic value, both are important unless the item has overwhelming provenance (an unreleased game) or overwhelming functionality (like a 3rd party debugging system). As EPROM carts they couldn't have been very expensive to buy from Nintendo either, just a little more than the ones frequently lent for review. These ones look like they're a little more robust for QA.

 

I don't really care about the collecors "value". I don't understand how anyone would pay so much for stadium events when you can have the same basic game for a couple of bucks. A lot of collectors do things that are irrational to other people that don't collect the same things (most commonly their wife!).

I don't collect because I can sell it for a lot of money later. Sometimes I find them really cheap, sometimes I pay more for things I don't have already. I make repros from non-dev carts when I want to make a repro, so I really don't "use" them. I collect because I like them. I don't collect proto games even though I have some to get dev boards I don't have. I just collect the circuit boards. That's my thing!

 

You hit the nail right on the head about the 2021. I don't have a camera with me, but mine is an "SHVC MULTI CHCKER-2021(A)" and just as you said has 8x8Mbit rom sockets. It also has a single 1Mbit/256k ram socket. It uses two AMPAL22V10APC FPALs and two toshiba 74HC138AP 3 to 8 line decoders. On top of that though it also has a number of things the other doesn't.

At the top of the board by the rom sockets are two 40pin female interfaces as though for either an addon board or debugger interface. Aside from that there's a push button switch and an LED that says battery check (not sure if the switch acts as a battery tester or not).

Oh, and it has a D411 CIC just like the other, but it's socketed, which I assume would be for pal/ntsc testing.

Edit: On second thought, now I'm sure that the connectors are for an addon as I just noticed that the board has standoffs that look just like something could plug onto those connectors and be screwed onto the standoffs.

 

Just think that for a collector this may be a very uncommon piece of hardware.

 

Here's the 2021. Tried the scanner and got a better shot. Doesn't look this distressed in real life though... Up to 48mb, a 20/21 switch, and an emergency button that causes the eproms to melt in a situation where you need to save your code from pirates...