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twistedsymphony

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Since there are a number of Irem games that were available on different hardware and a lot of conversions going on I thought I'd make a simple guide to telling them apart.

First of all you should check the print along the parameter of the PCB as it should clearly state "M72-X-X" or "M81-X-X" and so on. However if you can't read that label for whatever reason here is how you can ID the hardware type from the PCB's features:

if you can't read the labels here is a simple guide:


M72 = 3 PCB stack, JAMMA edge on center board, upper PCB is smaller and has a notch in the corner for the heat sync, also has 2 large ribon cables on one end and a 2 smaller harnesses on the other.
air_duel_jp.jpg

Original games on M72 hardware:
  • Air Duel (Also found on M82 hardware)
  • Battle Chopper/Mr HELI no Daibouken
  • Daiku no Gensan <Hammerin Harry> (Also found on M81, M82, and M84 hardware)
  • Dragon Breed (Also found on M81 hardware)
  • Gallop: Armed Police Unit <Cosmic Cop> (Also found on M84 hardware)
  • Image Fight
  • Legend of Hero Tonma
  • Ninja Spirit/Saigo no Nindou
  • R-Type [Not Viable for Conversion or Multi due to different ROM board]
  • X-Multiply (Also found on M81 hardware)



M81 = (looks nearly identical to M82) 2 board stack JAMMA edge is on the upper board and both boards are the same size, no cables between boards, note that there are 3 PCB connectors, 2 on the back edge, and unlike M82 there is one on the side near the front edge.
hh_m81.jpg

Original games on M81 hardware:
  • Dragon Breed (Also found on M72 hardware)
  • Hammerin Harry (Also found on M72, M82, and M84 hardware)
  • X-Multiply (Also found on M72 hardware)


M82 = (looks nearly identical to M81) 2 board stack JAMMA edge is on the upper board and both boards are the same size, no cables between boards, note that there are 2 PCB connectors, 2 on the back edge, and unlike M81 there is none on the side near the front edge.
majortitle_pcb_m82aa_partside.jpg

Original games on M82 hardware:
  • Air Duel (Also found on M72 hardware)
  • Daiku no Gensan <Hammerin Harry> (Also found on M72, M81, and M84 hardware)
  • Major Title


M84 = (looks nearly identical to M85) 2 board stack, JAMMA edge is on the lower board, upper board is half the size of the lower board, no cables between boards. note that there are 2 PCB connectors on the back edge, unlike M85 which are on either side
R-type2.jpg

Original games on M84 hardware:
  • Cosmic Cop <Gallop: Armed Police Unit> [M84-D-B Bottom Board, M84-B-B Top Board] (Also found on M72 hardware)
  • Hammerin Harry/Daiku no Gensan [M84-A-A Bottom Board, M84-C-A Top Board] (Also found on M72, M81, and M82 hardware)
  • Lightning Swords/Ken-Go [M84-D-B Bottom Board, M84-B-B Top Board]
  • R-Type II [M84-A-A Bottom Board, M84-B-A Top Board]



M85 = looks nearly identical to M84) 2 board stack, JAMMA edge is on the lower board, upper board is half the size of the lower board, no cables between boards. note that there are 2 PCB connectors on either side, unlike M84 which are both on the back edge
DSC_5225.JPG

Original games on M85 hardware:
  • Pound for Pound

These are not my photos. Thank you to those who pictures I borrowed :)
 
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This post is going to be very useful for many I think.
What about M85? There are at least 2 conversions available (R-Type and R-Type II) and more could be done. It's clearly the cheapest hardware amongst M72/M81/M82/M84/M85.

M84 has two variants for the motherboard and also two for the romboard.
M72 R-Type has a different romboard (really simpler, without samples support).
 
What about M85
added.

M84 has two variants for the motherboard and also two for the romboard.
M72 R-Type has a different romboard (really simpler, without samples support).
I tried to base the descriptions on the locations of the connectors as opposed to IDing based on the chips for this very reason. AFAIK the connector locations don't change based on the variants within the specific hardware sub-types.
 
added.
I tried to base the descriptions on the locations of the connectors as opposed to IDing based on the chips for this very reason. AFAIK the connector locations don't change based on the variants within the specific hardware sub-types.
My point was some boards can't be used for conversions. For instance on M84 Cosmic Cop and Kengo use a V35 CPU with embedded IRQ controller. It's totally possible to convert other games for this CPU but I don't see that happening.

[EDIT]
Following this topic I'm now wondering if the extra playfield supported by M82 wouldn't be supported by M84 or M85 too. I don't see Irem going backwards with the chips they used. Does anyone have hi-res pics of the bottom M82 board? Maybe M84/M85 (and even M81, who knows?) use the same chips but the additional ROM bank isn't wired.
The other possibility is Irem doubled the sprites circuitry on M82.
 
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My point was some boards can't be used for conversions.
Ah, I understand what you were getting at now.

I've added an "original" games list for each platform, added a note on R-Type about it not being viable for the multi, and added details on the M84 hardware about the different board variants.

it sounds like conversions on M84 would need to target a specific top or bottom board variant. Are there any limitations like this on the M81 or M82 hardware that you know of?
 
Thanks for this! This really sorts it out for me!
 
Following this topic I'm now wondering if the extra playfield supported by M82 wouldn't be supported by M84 or M85 too. I don't see Irem going backwards with the chips they used. Does anyone have hi-res pics of the bottom M82 board? Maybe M84/M85 (and even M81, who knows?) use the same chips but the additional ROM bank isn't wired.
The other possibility is Irem doubled the sprites circuitry on M82.
I have an M84 HH I'll take some pictures later tonight if no one else has any already.
 
it sounds like conversions on M84 would need to target a specific top or bottom board variant. Are there any limitations like this on the M81 or M82 hardware that you know of?
I can design a M84 multi that would fit both HH and RT2 motherboard.
I think all M81 and M82 boards are identical.
Thanks, I can see the two N/S jumpers to run decrypted/encrypted code.
 
Yep, Need to test it with unencrypted games - It's on the to-do list but the heat over here at the moment has made soldering not fun.
 
added.
I tried to base the descriptions on the locations of the connectors as opposed to IDing based on the chips for this very reason. AFAIK the connector locations don't change based on the variants within the specific hardware sub-types.
My point was some boards can't be used for conversions. For instance on M84 Cosmic Cop and Kengo use a V35 CPU with embedded IRQ controller. It's totally possible to convert other games for this CPU but I don't see that happening.
[EDIT]
Following this topic I'm now wondering if the extra playfield supported by M82 wouldn't be supported by M84 or M85 too. I don't see Irem going backwards with the chips they used. Does anyone have hi-res pics of the bottom M82 board? Maybe M84/M85 (and even M81, who knows?) use the same chips but the additional ROM bank isn't wired.
The other possibility is Irem doubled the sprites circuitry on M82.
Here’s a nice photo of the bottom M82 board, kudos to StefanL
majortitle_pcb_m82ba_partside.jpg
 
I tested cosmic on the kengo hardware.

Close, maybe a jumper problem, it's not line damage as kengo still runs.

EDIT : kengo factory pal cannot handle 2m program roms :/

EDIT 2 : tried splitting the rom and patched the rom test out of curiosity, game just hangs. so yeah pal issues.
 

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Here's a guy with an M81 that needs help and its for sale.

https://forums.arcade-museum.com/showthread.php?p=3876611#post3876611
Ahah I read your post there, thanks for the kind words.
I'd like to help but remote troubleshooting is always a pain. I mean when I have the board in my hands it takes me only few minutes to rule out power, vital signals (RESET, CLOCK, etc.) CPU, RAMs, ROMs, etc. But when you have to guide someone who doesn't necessarily have the tools and minimum knowledge (and I say that in a humble way, no offense) it can quickly get complicated.

Ok let's try anyway, first I don't have access to the pictures (not registered on KLOV, I can't be everywhere ;) ), then what is the exact problem?
Does sound work? Controls?
 
Is Air Duel a typo? Shouldn't that be R-Type II ? (system16.com/hardware.php?id=743)
no actually.
I went by MAME source, not system 16.

according to MAME source the only R-Type IIs on M82 were bootlegs.
https://github.com/mamedev/mame/blob/master/src/mame/drivers/m72.cpp
I see now. Interesting; never knew Air Duel was M82 too :)
Still have a spare M82 MT - Air Duel seems like a good target. Anybody know if that has than already been tried before?
 
Air duel works fine & is a simple rom swap.

There's another Load of games too patched for m82 by gadgetfreak, Cosmic cop, X Multi, Dragon Breed, Hammerin harry etc.

Also An 8 in 1 switcher in development, all games run but a couple need some work in the GFX rom switching department.
A schematic will be posted one day so you can do this yourself with a few wire mods.
 
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