Pr3tty F1y
Student
I recently picked up a ROUGH Irem Skins Game (from the roms, it's Set 2 in MAME) M92 board. This is the US version of Major Title II. Eventually I'm going to do a conversion on it, but I want to get it up to speed first.
Some small, fuzzy mammal definitely made a home in between the two board sandwich at some point in the past. There was some very neatly packed dirt in between the entirety of one of the 32pin DIP sockets to protect from the pins, some leaves, and plenty of small bits of dried plant material, spider webs, a few unlucky bugs - including a spider - that died and dried out under some of the ROM sockets, etc. The dirtiness (well, maybe not the packed dirt itself
) was clear from the pictures from the seller, but something still drew me to it anyway. I guess I'm a sucker for junk that may be gold.
That all being said, after I gave the board several rinses of isopropyl alcohol (which may or may not be the best choice of solvent, but my thought was that it would, at the very least, dry fast as I was eager to test the board) and scrubbed it down with a soft tooth brush, it cleaned up pretty well.
And, amazingly, it booted without issue on the first try. The graphics were a bit yellowy, but it played fine. I was amazed. There was no sound, but the potentiometer was working as I could hear the background buzz get louder when I turned it up so I figured the amp was OK.
So I removed all of the electrolytic capacitors which all seem to be near the audio portion of the board. C236 doesn't seem to be part of the audio, but replacing it seemed to boost the color balance back to where it should be. And, after recapping everything, still no audio.
I then removed and dumped all of the roms on my T56. All of the roms tested fine and matched Irem Skins Game (Set 2) in MAME except for MT2-SH0- which Xgpro gave a pin error on all but like 2 pins. The legs were straight, I tried cleaning them, but nothing. So I burned a new 27C512 and replaced it and - BOOM - audio is working great!
Which now brings me to the RAM errors. Sometimes when I boot the game, it boots fine and it says RAM OK, other times, I get an ever changing series of RAM errors.
My questions are:
The game looks great overall, even with the RAM errors:
But there is clearly some corruption with the layering and either the row across the green being corrupt/transparent or the column down the leader board being corrupt and/or missing:
Here's what the board ended up looking like after the initial cleaning (pre-recapping). It's dirty/rough, but the components are not rusted or corroded (the only rust seems to be on the support post screws). It may be on the verge of starting some light corrosion, but the solder on the custom chips is silver and shiny like it was brand new. I'm really perplexed about why some of it looks good and other places more rough. I'm not sure of how it was stored. All I know is that it was hilariously dirty, the green lacquer of the board wipes off green a bit in spots near the JAMMA edge connector with any moist wiping (water, isopropyl, etc.), and the bottom board seemed a quite bit rougher than the top board. The boards came assembled and screwed together tight. I had to break the rust on the support post screws, so I don't think the board interconnect pins were exposed. This thing seems to have been left bolted together for a very long time:
Some small, fuzzy mammal definitely made a home in between the two board sandwich at some point in the past. There was some very neatly packed dirt in between the entirety of one of the 32pin DIP sockets to protect from the pins, some leaves, and plenty of small bits of dried plant material, spider webs, a few unlucky bugs - including a spider - that died and dried out under some of the ROM sockets, etc. The dirtiness (well, maybe not the packed dirt itself
) was clear from the pictures from the seller, but something still drew me to it anyway. I guess I'm a sucker for junk that may be gold.That all being said, after I gave the board several rinses of isopropyl alcohol (which may or may not be the best choice of solvent, but my thought was that it would, at the very least, dry fast as I was eager to test the board
) and scrubbed it down with a soft tooth brush, it cleaned up pretty well.And, amazingly, it booted without issue on the first try. The graphics were a bit yellowy, but it played fine. I was amazed. There was no sound, but the potentiometer was working as I could hear the background buzz get louder when I turned it up so I figured the amp was OK.
So I removed all of the electrolytic capacitors which all seem to be near the audio portion of the board. C236 doesn't seem to be part of the audio, but replacing it seemed to boost the color balance back to where it should be. And, after recapping everything, still no audio.
I then removed and dumped all of the roms on my T56. All of the roms tested fine and matched Irem Skins Game (Set 2) in MAME except for MT2-SH0- which Xgpro gave a pin error on all but like 2 pins. The legs were straight, I tried cleaning them, but nothing. So I burned a new 27C512 and replaced it and - BOOM - audio is working great!
Which now brings me to the RAM errors. Sometimes when I boot the game, it boots fine and it says RAM OK, other times, I get an ever changing series of RAM errors.
My questions are:
- Due to the condition of the board, is it possible that multiple RAM chips failed?
- I know that anything is possible but....
- Although the board was rough, it still seems wild that I'd have multiple different types of SRAM chips fail when the board overall works fairly well
- Is there something else that could be causing the RAM issues?
- Like maybe the interconnects between the two boards not making a good connection?
- Or a failure of one type of RAM cascading and causing failure of other types of RAM
- Maybe a LS logic chip fizzling out, but I'm not sure which ones would affect all of the various RAM types
- Could it be something else?
- I'm willing to entertain anything as I really want to get this thing working
The game looks great overall, even with the RAM errors:
But there is clearly some corruption with the layering and either the row across the green being corrupt/transparent or the column down the leader board being corrupt and/or missing:
Here's what the board ended up looking like after the initial cleaning (pre-recapping). It's dirty/rough, but the components are not rusted or corroded (the only rust seems to be on the support post screws). It may be on the verge of starting some light corrosion, but the solder on the custom chips is silver and shiny like it was brand new. I'm really perplexed about why some of it looks good and other places more rough. I'm not sure of how it was stored. All I know is that it was hilariously dirty, the green lacquer of the board wipes off green a bit in spots near the JAMMA edge connector with any moist wiping (water, isopropyl, etc.), and the bottom board seemed a quite bit rougher than the top board. The boards came assembled and screwed together tight. I had to break the rust on the support post screws, so I don't think the board interconnect pins were exposed. This thing seems to have been left bolted together for a very long time:
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But with the relatively clear graphic corruption, despite getting the error messages or not, I'm figuring at least something is bad RAM wise.