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SOLVED: Did I fry my CPS2 boards with 5.18V?

stringbean

stringbean

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I have an Astro City with one of the 400-5198 PSUs like this one:
400-5198-front.JPG


I have been trying to debug some issues with the new Darksoft Champion CPS2 MultiKit that I've been having and tested the +5v voltage on the PSU using the DC Out 1 the same way this guy does in this YouTube video. Basically, what I saw was the PSU was delivering 5.18V of power instead of between 5-5.1V which people have been recommending. What I'm wondering is whether that could be a high enough voltage to fry a CPS2 board. Because, two separate CPS2 boards that seemed perfectly functional when I plugged them in are now showing a jumbled mess on the monitor or simply a black screen when I plug them in and I'm very worried I've somehow damaged them.

The first was my original CPS2 which had Street Fighter Alpha 2 on it. Originally, after restoring this Astro City cab (and never checking the voltage being delivered by the PSU) I had this in the cab. It played perfectly fine for months without any issues. Then, I tried to install CPS2 Multi Kit on it and it started showing scrambled mess of colors on the monitor as follows:
3Jej8ZI.jpg


I thought for sure it had to do with the Multi Kit since everything was working just fine before, but then I tried a bunch of debugging steps and wasn't sure so finally I re-inserted the original ROM chips in the B board and the same issue remained. I wanted to run through some other debugging steps but went ahead and bought another CPS2 in my local area and plugged that in today. At first, for about 10 min or so I ran it and it was running perfectly. Sound was good, picture was good, everything just fine. Then, I unplugged it and started disassembling it because I wanted to install the Multi Kit in it. But, just to be sure I thought I better check/adjust the voltage before doing that. So, I plugged the x-men vs street fighter back into the Astro City and fired it up again in order to check and adjust the voltage. Except this time, the screen just showed black. Then, after a short while it started showing a similar jumbled mess of colors as my other CPS2 board. Worse yet, I had adjusted the game in settings to be on free play so I thought if I wait a while and then press the start button maybe I could hear the sound of the game. But nothing worked. Then, I went ahead and tested the voltage and noticed it was at 5.18V so I immediately adjusted it down to 5.04V. Here is the screen that showed on the xmen vs street fighter.

dVTyRMq.jpg


I immediately shut it off, but obviously by now if it did fry the board the damage is done. So, then, because things couldn't possibly get worse I went ahead and turned it back on to see what showed and it only shows a purple screen with some discoloration in the bottom right corner. Have I just destroyed a bunch of hardware?
 
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Often times solid color screens are a failure of the key writing/decryption process.
stringbean said:
shows a purple screen with some discoloration in the bottom right corner
Click to expand...
I'd be willing to bet the slight discoloration in the bottom right is the CRT picking up magnetic interference.

P.S. I always run ALL my arcade boards at 5.18v, some (MK) like a little extra and I can't be bothered to adjust it every time.
Easiest way to damage a arcade board is plugging the JAMMA harness in backwards/upside-down (I've also done this).
 
Often times CPS2 not showing up is poor connection between the boards, but I am sure you already checked that plenty.
 
Shorting CC1 and EXE5 was the "old" method that could clear a previous written key.
You may want to try it (at least the CC1).

When I intentionally suicided MvC (my donar board for the multi) by cutting off the battery, the key didn't actually clear until I shorted CC1.
Hence I only got the solid color screens when first installing the kit.

I found it funny because in the past I would worry about batteries failing and the keys getting wiped constantly.
Turns out if the board has been recently used (caps still holding a charge) you can cut it completely off and it still stores the key until that charge is gone.
 
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I've ran a CPS2 board at 5.5V+ for a brief while, because the voltage adjustment pot on the Hantarex PSU I had connected it to works in reverse (so turning counter clockwise the voltage actually goes up). I thought I had at it the bare minimum and in reality it was on full blast.

Anyway, I would be extremely surprised if 5.18V has done damage to your boards.

Try seating the boards together without the casings.
 
Typical 5% tolerance makes voltage up to 5.25V acceptable (although not optimal) so it's very unlikely you've broken your CPS2 due to this. I'd clean the pins and reconnect the boards.
 
Thanks for the feedback y'all. I'm gonna try some more stuff today and see if I can get these boards playing again.
 
Did you test the voltages actually under load? Meaning, test while the cps2 board was connected? Also, test at the cps2 board jamma edge.
 
Anselmo said:
Did you test the voltages actually under load? Meaning, test while the cps2 board was connected? Also, test at the cps2 board jamma edge.
Click to expand...
I didn't check directly on the edge connector but I'll do that today. All my tests were done under load.
 
Okay, this is really weird. I removed the CPS2 from all shells and checked all the +5V pins and the +12V pins on the edge connector under load. The 5V was reading at 4.93V and the 12V at 11.97V. Then, I went back to the PSU and checked the 5V output there and it is reading 5.04V. How is that even possible? I guess I should adjust the PSU back up so the voltage is ~5V at the edge connector?
 
I adjusted the voltage back up on the PSU until it read 5.07V at the edge connector and then read the voltage on the PSU which was back at 5.18V - the original voltage. Double and triple checked to make sure the connection between A & B boards is solid. After powering on, I see a blackish purple screen with discoloration on the bottom right corner as mentioned previously. Out of curiosity, I also measured the voltage on the B board battery which came in at 3.69V. Then, I hit the coin switch several times after the game would have had an opportunity to start and didn't hear any coin sounds.
 
on the astros, one thing I noticed is that the jamma connector is not keyed, and it's easy to install it off center. Do you think that's something you could have done?

Can you test the boards on your blast?
 
stringbean said:
Okay, this is really weird. I removed the CPS2 from all shells and checked all the +5V pins and the +12V pins on the edge connector under load. The 5V was reading at 4.93V and the 12V at 11.97V. Then, I went back to the PSU and checked the 5V output there and it is reading 5.04V. How is that even possible? I guess I should adjust the PSU back up so the voltage is ~5V at the edge connector?
Click to expand...
Yeah, 5V at jamma edge is OK. That's the place to measure the voltages the board is getting.

Voltage drop is usually caused by not enough copper wire gauge (specially low gauge long cables) and/or power connectors in bad condition. What cables are you using for GND and +5V? anyway that voltage drop should not be the problem.
 
stringbean said:
Okay, this is really weird. I removed the CPS2 from all shells and checked all the +5V pins and the +12V pins on the edge connector under load. The 5V was reading at 4.93V and the 12V at 11.97V. Then, I went back to the PSU and checked the 5V output there and it is reading 5.04V. How is that even possible? I guess I should adjust the PSU back up so the voltage is ~5V at the edge connector?
Click to expand...
That's completely normal. wires and PCBs have a natural resistance that will cause a voltage drop from one end compared to the other. The thinner wire and the longer the wire the more of a voltage drop there will be but it will always be there to some degree.

The video you posted that shows how to do it is actually showing the WRONG way to do it. what you did by measuring the voltage on the pins on the actual PCB is the RIGHT way. Given that the CPS2 has a case, then measuring it on the JAMMA edge is good enough to be close enough, but for other pcbs it's best to measure and adjust the voltage based on chips pins on the PCB itself. if you want it to be the most accurate.

As others have said, based on your symptoms it sounds like your multi kit isn't writing keys properly or there is an issue between the PCBs and they need to be reseated.
 
I think some of the way I worded the original post made it confusing. The X-Men vs Street Fighter CPS2 board still has the battery installed which it came with when I bought it a few days ago. The battery voltage reads 3.69V and it was working perfectly before I must have done something to break it - albeit I was so excited about the prospect of having a board to install the multi kit on that I only tested it for ~10 min or so after unboxing it. My other CPS2 board is an Alpha 2 Asia model and that is the one I had tried to install the multi kit in. That board had a very similar issue and is the reason I bought the X-Men vs Street Fighter.

@Anselmo, I just tried the X-Men vs Street Fighter board in my Blast and had the same results. At first, it powered on with a black screen and then about 30 seconds afterwards it turned into all the jumbled colors. The A & B boards had a good connection and I even tried (although didn't take photos) unshelling the A & B boards and running the game like that. This was the only way I could use the multimeter to test the voltages on the edge connector since the case only has a tiny amount of space between the Jamma connector and shell housing.

Here it is after the initial power on in the blast city.

y7b99Kh.jpg


And here after about 30 seconds or so. This is the same stuff displayed when it is connected to the Astro City.
dBtVxAZ.jpg


I read the voltage on the CPS2 B board battery and it reads 3.69V which falls right in line with what I'm seeing people mention is correct.
 
pacoarcade said:
Voltage drop is usually caused by not enough copper wire gauge (specially low gauge long cables) and/or power connectors in bad condition. What cables are you using for GND and +5V? anyway that voltage drop should not be the problem.
Click to expand...
Nothing special. I just have the original JAMMA cables that each cabinet came with.
 
sounds like you might have a bad cps2 A board, I have had that problem as well.
Do you have another A board?
 
kingau said:
sounds like you might have a bad cps2 A board, I have had that problem as well.
Do you have another A board?
Click to expand...
At the moment I have two CPS 2 boards which are both experiencing problems. Unfortunately, one is an Asia model and this one is a USA model. I may buy another USA A board, but I'm very worried that this same issue will happen to that board as well and I'll be back in the same position.
 
Okay, so last week @Anselmo was nice enough to sell me a cheap USA A board. I connected it up to the X-men vs Street Fighter B board I have and threw it in my Blast City (I haven't put it in the Astro City yet) and saw some success. The game boots and plays! But, there are these horrific vertical bars. See here for a video. This seems to indicate that whatever happened may have damaged the A and B boards? This is getting very weird. Is it possible the ROM data has become corrupted? I've heard of people getting the ROM programmers and validating each chips data for NEO GEO games. Maybe I should do something like that or possibly reprogram these chips if possible. If anyone else has seen and fixed something like this in the past, I would be very interested to hear your experience.

tCXhioC.jpg
 
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