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My CPS2 board has issues. Should I still install the kit?

Yes, I was booting them in the shells. They were as tight as I could get them. Is it worth trying it with both boards naked?
 
the bottom board doesn't have to be decased... if you take off the plastics on the top board you can know for sure it's fully seated. If the top plastic shell is missing any of the plastic standoffs the pcb is able to move upwards into the case. When you press the halves together the top pcb can shift upwards instead of firmly seating onto the motherboard.
 
Under load means the pcb is plugged in. Just making sure you’re doing it right. You plugged in the pcb to your supergun, turned on the power, and ready 5.0x volts off the GND and 5v jamma pins (e.g. 1 and 3) using a multimeter?

if you measured 5.09 from the supergun before plugging in the pcb, that’s probably the issue. If you’re just reading a voltmeter stuck on the supergun, that’s also not great unless you’ve also calibrated THAT with a multimeter (those voltmeters are adjustable). Sorry to be pedantic but power is key.
 
Sorry, I’m just not following you. The supergun was reading 5.09V while the board was on. The only reason I can tell the voltage on the supergun under load is because it has a built-in voltmeter. The only way I know of to check voltage on a cabinet’s jamma edge is with a multimeter. But if there’s a PCB connected to the jamma edge, I can’t stick the prongs on the multimeter in because there’s already something there. I’m sure I’m just missing something due to inexperience here...
 
View: https://youtu.be/vkMZRKH0h-c


Old video but the concepts are in there. For any chip you can look up the pinout online to see which pins are gnd and which are 5v. But you don’t even need to do that… cps2 is probably in a shell anyway. Just touch your probe tips to pin 1 and 3 of the jamma edge. I doubt your edge connector covers those pins completely. Something like here in red (positive tip) and green (ground).

39844833-52DA-40BE-8200-B8CC36D66ED8.jpeg


Heck you can even check on the supergun’s or jamma harness’s respective pins where the edge connector is soldered, if you can’t reach the pcb due to the a board shell. I just don’t trust the supergun voltmeter until you’ve checked it with a multimeter.

maybe power isn’t your problem but it’s easy to rule out! The chips want 5v but the edge is an OK proxy. For cps2 you can run e.g. 5.08 on the edge and there will be some drop between there and the B board, so the B board may only see e.g. 5.00.
 
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The reason people say to check the 5v on the pcb, or even at the chips, is because everything that conducts electricity is a resistor. There are no perfect conductors. If you have a harness made out of 22 AWG wire, the length of the wire alone will cause a small voltage drop. If your connectors are dirty or oxidized this also causes resistance which lowers voltage. So you might check your 5v at the PSU and see it's at 5.01v and you think great! but then you check at the jamma edge and it's 4.8? then you check at the chips and its 4.7? these are hypothetical numbers, but realistic. A lot of chips can't operate correctly under 4.8v.

another thing people don't realize because they don't usually check their 5v every time they change pcbs... the actual voltage you see at the edge will vary based on the amount of current that the board draws. This is just the nature of how arcade power supplies work. I would say CPS2 is above average in terms of current... but not awful. So if you put in say a single side pcb board like Atari Tetris and set your power supply 5v... don't think you can just plug in a CPS2. You will need to adjust the 5v because it has a significantly different amperage. So... because the output voltage varies based on the load, that is why there is not much point to measuring your 5v without the pcb attached.
 
Neat! I didn't know you could do that. Thanks for the info. I'll definitely keep that in mind going forward.

Fixing the B board doesn't really seem to be a realistic option for me, so I think I'm going to have to bite the bullet and buy another one. Unfortunately, right now the cheapest one on eBay from a US seller is $200. Damn, this getting expensive...

I really appreciate all the helpful suggestions.
 
ShiftingBlank said:
Fixing the B board doesn't really seem to be a realistic option for me, so I think I'm going to have to bite the bullet and buy another one. Unfortunately, right now the cheapest one on eBay from a US seller is $200. Damn, this getting expensive....
Click to expand...
Couple of B boards for sale here.
 
Hammy said:
There is a razoola CPS2 test rom, burn it and it should have work ram test among others.
Give that a spin and post the results!
Click to expand...
To boot it needs most of the hardware to be good. For instance if work RAMs are bad and fail in a way they pull data high (happens quite often) or if Q sound fails to initialise you'll be only greated by a black screen.
 
I bought a SSF2X B board from Jap and it seemed great. Then, after some-time (5seconds to 50mins) it will get graphics corruption and end up freezing. I battled with it a lot and even tried a known-working multi board in it, also tried known-working roms/etc from a working B board (changed the jumpers etc to match). I could never get the thing to work properly, even recapped it. Long story short, I think you may need to get another before putting a multi kit in there.

The multi kit and all the roms/etc I tested all worked fine when I put them back into their original donor B boards.

I assume it was one of the custom chips. Checked all the legs under a good microscope, still couldnt figure it out. Still not working properly. Dont be me :) Buy a working/good board and multi "it". Goodluck.
 
So I went and bought one of Brad's working CPS2 B boards (Darkstalkers). It just got here today. I plugged it in, and... the same damn thing happened. I can't really check the voltage on the JAMMA edge under load without decasing everything, but I tried the board with a reading of 5.09V under load on the supergun's voltmeter, then with 5.25V cold on a cabinet for good measure, and I had the same results: about one minute of normal functionality, then the video starts cutting out, then it starts resetting (the other board crashed rather than reset), and eventually it won't display anything.

It's got to be the A board then, right? I'm at the end of my rope here, guys...
 
I took both boards (the old A board and new B board) out of their cases and cleaned them thoroughly. Except for the edge connector pins, the A board looks pristine to me. I cleaned the pins (again) with a pencil eraser and isopropyl alcohol on both sides, then seated the B board just right and tried again. Same thing. I checked the voltage under load at the JAMMA edge, and it was exactly 5V. Either I did something to incur the wrath of the video game gods, or, despite all appearances, the A board has actually been the problem all along. Is there any other possibility here?
 
If the B board was confirmed working before it was sent to you then it definitely sounds like the A board is the faulty one. Pick up another one, test things out, and you can sell of your spare B board afterward if it works alright.
 
It was the A board. I got a new one today, and the Darkstalkers B board worked fine. So I reinstalled the multi kit in the SFZ board I'd already removed the EEPROMs from, and I still had weird vertical lines in certain background tiles. After reconnecting the A and B boards multiple times and makings sure the kit was seated properly, I decided to remove the kit from the SFZ board and install it in the Darkstalkers board. That's when one of the long pins on the small multi board snapped off.

So... how do I get the broken pin replaced? Can I send the board to someone? I'm in Maine.
 
ShiftingBlank said:
I'm trying to decide whether or not to go ahead and install the kit anyway.
Click to expand...
Definitely not. First fix it and then install the kit. You don't want to be in the situation where you dont know if the problem is from your CPS2 Setup or your multi.
 
Well, in case anybody's curious, I eventually got this thing up and running. As far as I can tell, I actually had bad A and B boards. Guess that's what I get for trying to save a few bucks by ordering used stuff from China. I thought $300 for both seemed too good to be true...

If I had to do it over again, I'd definitely get CPS2 hardware from a reliable domestic seller, or at least one who takes returns. It seems like this stuff is fairly failure-prone.

Anyway, thanks to everyone for all the advice, and thanks to Mitsurugi-w for fixing my board so quickly.

So everything's working well enough now, but I still have a couple of minor issues. Maybe somebody has run into these before:

1) My CPS2 board resets the volume to zero when I turn it off, so every time I turn my cabinet on, I have to reach in and manually crank the volume back upon the A board. Oddly enough, this only happens if I leave the cabinet off for about half an hour or longer. Weird.

2) I had to switch from encrypted to decrypted ROMs because the new board I got doesn't have a plug for the key-writing cable and I don't really know how to solder (maybe I'll use my non-working CPS2 stuff as scrap boards and finally learn). Now every time I switch games, the unit still tries to apply a key, and the new game crashes. If I turn everything off and back on, the game starts up fine. Do I need to somehow tell the kit to stop trying to write keys?

3) The decrypted ROM set doesn't seem to have the ports of CPS1-1.5 games. Are those only available if you're using encrypted ROMs, or I using an old set? It's listed as "OLD" and it's from 2019, so...

These things are all just annoyances, but it would be awesome if I could fix them somehow.
 
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