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Kujako

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Looking to move my sketchy CPS1 multi board to a new 'A' PCB due to the old one being bad. Anyone know what modifications if any are required? It looks like it just uses a single reset wire, but with all the iffy repairs that are on my current 'A' board I'm not sure if any of them are related to the multi.

Update: See below for what I've tried and what isn't working...
 
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Looking to move my sketchy CPS1 multi board to a new 'A' PCB due to the old one being bad. Anyone know what modifications if any are required? It looks like it just uses a single reset wire, but with all the iffy repairs that are on my current 'A' board I'm not sure if any of them are related to the multi.
 

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@AlxUnderBase Thanks, mine is a little different but it looks like the same reset pin (mine connects on top).

IMG_0858.jpg
 
@AlxUnderBase related question: Does your board have kick harness connectors? I have two that look like CPS1 kick connectors, but I'm really not sure what they do so I've never wired anything up to them...
 
The story so far. Many years ago, when I was young and foolish I picked up a CPS1 32-in-1 board from China. It frankly worked really well for quite some time. But recently it started to have audio issues (thinking it's the z80). I pulled it apart, and found a large number of questionable repairs, but nothing that looked too out of place. It was a 10mhz board that had been upgraded to 12mhz by having the crystal swapped, most of the capacitors had been replaced (poorly and not sure with new capacitors) and there's a weird diode replacement job (see pic). I also had a clean SF2 WW board set, so my thoughts were to use it as a diagnostics platform. When I connect the board, it boots and runs (with audio thus showing the audio issues were on the old A board and not the B+C multiboard). But with heavy graphics corruption. I thought that MIGHT be related to the 10mhz crystal, but after swapping those I'm still seeing the same issues. I did confirm that the pin shown here earlier does reset the board. So that's one mystery down.

Really not sure what the deal is. What other than the crystal could have been changed out that would cause graphics issues if it were missing?

(diode weirdness - and note that the crystal shown here has no markings so can't be sure it wasn't replaced)
Edit: Chip is a rebranded YM2151. Diode is running to pin 22 which is +5v (vdd). So while weird looking, it seems to be right.
Edit: Thinking about it, the sound issues may be because of a faulty crystal on the z80. So that blank one may be the issue. Guess I just need to find a 3.579545mhz full can crystal to test that theory with.
IMG_0869.jpg


One thing I have now noticed, is that the CPU on the old board (Chinese bodge job with failing audio) has a 12mhz 6800 in addition to the 12mhz crystal.
 
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Swapped the 3.579545mhz crystals between the two boards, that’s not the failure point. Despite being unlabeled the crystal from the bad board seems to work in the good one and the bad boards issues are not resolved by changing out the crystal. Down to thinking it’s the Yamaha or z80.
 
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Sourced a YM2151, having problems finding a YM3012 on this side of the planet. Also think I have a Z80a around here somewhere. Will try "piggybacking" the Yamaha chips, think I would need to remove and replace the Z80.
 
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Could also be the line driver (LS367A) it's clearly been replaced, poorly, at some point. Lot's of nasty flux residue and the pins are not properly lined up. I don't see anything under my lil' inspection scope. But that doesn't mean the pins are making proper contact.

IMG_0870.jpg


Quick Camera Image 2021-05-10 at 5.54.18 AM.png
 
My multi has corrupted graphics too, I'm pretty sure it's the memory chips on the B board as I've tried known good A and C boards with it and it still happens. Assuming you've got the same multi as me, from what I've read on here the voltages to the memory chips on the B board aren't properly filtered so it's just a matter of when not if they will die (I'm just parroting what I've read though, I don't really understand that stuff! 😅)
 
My multi has corrupted graphics too, I'm pretty sure it's the memory chips on the B board as I've tried known good A and C boards with it and it still happens. Assuming you've got the same multi as me, from what I've read on here the voltages to the memory chips on the B board aren't properly filtered so it's just a matter of when not if they will die (I'm just parroting what I've read though, I don't really understand that stuff! 😅)
In my case, I'm 100% ~80% sure it's the 'A' board. No graphics issues on the 12mhz board it came with, but no sound. If I put the multi B+C boards onto a good 10mhz board, I get sound but bad graphics. So the ROMs are good, between the two 'A' boards I can confirm that I have good graphics and sound. So need to either get another 12mhz A-board, or fix the one I have.

I've also run a good SF2-WW board on the bad A-board and there are no issues other than the sound.
 
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I am increasingly flummoxed by the diode on the Yamaha clone. It's where a capacitor should be according to the screen and it drops the voltage to the 5v pin down to close to 4. I just don't understand what it's doing there... looking over the diagrams, shows neither capacitor nor diode. The more I look at it, the more it seems to be a factory install, but I really can't figure out what it's doing. Big problem is it's in the way so I cant piggyback a new chip to see if it works.

Edit: So this seems to be common with the Chinese "build a working board from whatever is in the bin" method. But I really have no idea why it's wired up this way. But I'll keep it as is, pulling power from the capacitor pad, and drop in a socket for a replacement chip.
IMG_0870.jpeg
 
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Replaced the z80, and not have no picture... must have mucked somthing up. Will try again later.

Edit: And later came. Reflowed the solder, and it's working now. At least as well as it has been. Still no sound. So, not the z80!
 
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Replaced both the Yamaha sound chips, tested the output of the YM3012 with an oscilloscope and just see some background noise that I can also hear if I crank up the amplifier volume. So thinking it's somewhere before the YM3012... may be the LS367A, but really not sure how I would test that (no replacements and I hates SMD soldering).
 
Got a new CPS-1 "Dash" A-board, dropped on my multi B+C and it works. So that's good, at least I can confirm that there's nothing funky about the B-C board requirements.
 
Did you make any progress on this? I have a similar hack board and my issue is any music playing causes the audio to go away entirely. In forgotten worlds, the attack mode sound effects work. As soon as you coin up the game, all audio is gone.

https://www.arcade-projects.com/threads/chinese-hack-forgotten-worlds-conversion-audio-broken.24020/
I've not worked on it since last year. And in fact have since moved onto a Darksoft Multi-CPS1. But it is something I'll revisit, I just have a lot of projects on my bench right now...
 
Remembering why I shelved this project and it's sibling. These systems are a pain to work on, since everything I want to poke at is under the game board. I know there are repair rigs to help with this. But I've never been able to justify the cost.

On a whim I did go ahead and socket/replace the SRAM chip @duffcon spoke about in their thread, but no effect. Did have a moment of elevated expectations when it turned out the chip that was in there had a bad leg (can see the shortened leg pictured here. Left most pin, shown next to its replacement), but nada.

1672435275605.jpeg
 
I have a multi cps1 32 in 1 chinese that presents the following problem: the weak kick works alone randomly. What can it be?
 
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