mv1fz 2 player start stopped working

mr aize · Jun 2, 2013

Hi, bit of an odd problem, but the start for my player 2 has just suddenly stopped working. I'm absolutely certain it's not the button or the jamma harness since i've got continuity right up to the jamma edge, I did the battery mod on it ages ago so don't think any traces could have suddenly eaten through... It was working yesterday with a multicart in and suddenly stopped working when we changed games, now it doesn't work with any of my other carts either. I'll take the cover off and have a really close look later, but could anyone give me some pointers for where to look. Thanks.

Craig · Jun 2, 2013

checked to see if the microswitch is dead?

mr aize · Jun 2, 2013

Thanks but yeah, i'm certain it's a problem on the board, not the button/harness as i've swapped them around and tried just shorting out the wires with no luck.

Xian Xi · Jun 2, 2013

Trace it back to one of the resistor networks (Black flat things) and with a multimeter check the resistance (ohm) from pin 1(VCC) to the pairs:

Pin 1 - VCC
Pin 2 - 1K
Pin 3 - 220ohm or 330ohm
Pin 4 - 1K
Pin 5 - 220ohm or 330ohm
Pin 6 - 1K
Pin 7 - 220ohm or 330ohm
Pin 8 - 1K
Pin 9 - 220ohm or 330ohm
Pin 10 - Ground

If you test resistance from Pin 1 to Pin 2 it should say 1k, if you test from pin 1 to pin 3 it should say 1.2k or 1.3k. If you test from pin 2 to pin 3 it should be 220ohm or 330ohm.

The input signals from the jamma edge go to the 1K pins and the output pins(220 or 330ohm) go to the IC that handles the input signals. So if the input/output is bad then you need to swap out the resistor network with a working one or build a new one.

mr aize · Jun 2, 2013

Hi there, do you mean the red things in this picture? Ta

Bottom right.

Oh, an thanks btw.

mr aize · Jun 3, 2013

Ok, so checked all the resistor networks. All of them test out ok, far as I can see. Testing with one pin on vcc i'm getting roughly 1k, 1.2k, 1k, 1.2k etc up to ground which is about 340 ohms. I reflowed the solder around the pins as a few were slightly cracked, but no change. Unfortunately someone's put lots of hot glue holding all the capacitors onto the board so i can't really see the traces too well. Don't suppose you know which ic controls input signals? Want to check for any corroded pins etc.

Finally, my jamma harness goes to a db15 connector, to plug in a controller, so i will triple check this again, but i really can't see how that could be the problem, because how would it suddenly develop a short and stop working mid session?

Once again, thanks a lot, really appreciate the info.

(Btw, that's not my board in the pick above, just found a pic on google to ask layout questions)

Xian Xi · Jun 3, 2013

Usually it's handled by a Neo-C1, I'm not sure if the FZ has one though.

Also make sure you have continuity from the edge to the Resistor network, sometimes the ferrite beads get corroded.

Xian Xi · Jun 3, 2013

Forgot to say, also try clearing your backup RAM.

mr aize · Jun 3, 2013

Hmmm, well further interesting developments. I do have continuity between the edge and the resistors. Tried clearing backup ram (booted without a cart in, cycled through options pressing start, then pressed abc. Just jumped to the next screen (set clock). Booted up game (waku waku 7) still can't start with player 2 (join in) also, the clock was stuck on 00 so the game ended almost immediately. Cleared ram again and the clock is back to normal, but p2 start still doesn't work. Did a hardware test (screen 2 I think when booting without cart in) and p2 start shows up as working. Could the ram be dying?

mr aize · Jun 3, 2013

oh, also tried bridging out the edge connector u (p2 start) with ground and very occasionally it does work.

ne7 · Jun 3, 2013

you tried swapping out the replacement battery you did the mod with yet? I should think a drained bat could make all sorts of fun things happen with the backup ram

mr aize · Jun 4, 2013

Hmmmm, ta, not tried that. I'll give it a go but it was only a couple of years ago I did the mod, thought the batteries were supposed to last ages as it used so little...

mr aize · Jun 4, 2013

Ok, thanks for the idea but just checked the battery an it's still putting out 3v so not gonna be that. Any other ideas? Can't understand why it would show up as registering the input on the test menu but then not work in game...

Xian Xi · Jun 4, 2013

Flip all the dips on and run the work RAM test for about 10 minutes, if after 10 minutes the screen still says "WORK RAM TEST" then the Work RAM is still good.

mr aize · Jun 4, 2013

Thanks, doing it now..

mr aize · Jun 4, 2013

Right, work ram tests out ok. Just checked my mv1b in the same harness and it works just fine so definitely, definitely a problem with the board...

mr aize · Jun 4, 2013

Holy crap Massive Facepalm!!! I've found the problem, i've got an old unibios 2.3 and I vaguely remember changing the bios to usa, (had a few people over, were all pretty pissed, totally slipped my mind) because the euro version of bomberman was in spanish. Turns out that the usa bios is for a machine with 2 coin slots, whereas mine is wired for one, so whenever I credited, it only went to player one, so I could never start a 2 player game... Had no idea this could even happen... A thousand apologies Xian xi and everyone else for wasting your time and thank you so much for your help... Feel like a complete berk now!

Xian Xi · Jun 4, 2013

LOL, same here. I didn't even pay attention to what button it was. Well if someone has a problem with a button other than start then they at least know how to check it.

mv1fz 2 player start stopped working

mr aize

Dodgeball Yakuza

Craig

Stupid Bitch.,

mr aize

Dodgeball Yakuza

Xian Xi

JammaNationX,

mr aize

Dodgeball Yakuza

mr aize

Dodgeball Yakuza

Xian Xi

JammaNationX,

Xian Xi

JammaNationX,

mr aize

Dodgeball Yakuza

mr aize

Dodgeball Yakuza

ne7

Armored Scrum Object

mr aize

Dodgeball Yakuza

mr aize

Dodgeball Yakuza

Xian Xi

JammaNationX,

mr aize

Dodgeball Yakuza

mr aize

Dodgeball Yakuza

mr aize

Dodgeball Yakuza

Xian Xi

JammaNationX,