Problem with my Ms. Pac..please help

[2PacMan]

I have a Ms. Pacman upright arcade game.  When I play it, it works fine for about 15 minutes, then the screen goes black and random rainbow colored shapes appear in the upper left hand corner.  Then if I turn it off and back on, it works for a minute and does it again.  If I leave it off for a few hours, I can play for a while again.  I

[APFelon]

Maybe I can help with this part...

Also, I

[paigeoliver]

Those cabinets never had bulbs back there.

Maybe I missed it in your post, but you forgot to clarify the single most important thing in troubleshooting your problem.

When the monitor goofs up does the game itself keep playing? Can you still coin it up and here Ms. Pac and the music and all?

[fredster]

Sounds like a thermally intermittent ram problem.

To find the chip, go to Radio shack and get a can of "freeze" spray.  Open up the back of your game and wait for the problem.

Take the can and zap each of the ram chips with the spray, one at a time, and look for the machine to boot.  When the machine boots after you cool the chip, you found it.  That's how it's done.  You will need to desolder the chip and put a new one in.

For all the chips and lights for your machine, go to www.therealbobroberts.com and ask Bob.  He'll give you one of the better deals on chips + parts and advice.

If you are a clutz when it comes to such matters then I suggest you send the board out for repair.  You can find somebody on rgvac who fixes those boards.  It would cost you about $75 (plus shipping) to get that fixed.

[2PacMan]

Sorry...let me clarify things.  When the game goes out, it's just a black screen with either one, or sometimes four or five flashing symbols that flicker in many different colors.  I can't play the game, hear it, or put credits on it.

I couldn't play it at all yesterday, so i imagine it's fried for good.  I turn on the machine and it just automatically goes to the black screen with the flickering symbols.  They aren't numbers or anything, it's mainly the flashing fruit symbols.  I was reading something that says there's a 'watchdog' chip in those Ms Pac games that will freeze the game if something's going wrong...could that be it? 

The original guy i bought it from says it 'overheats' and that's why it glitches out after a while of playing and that it needs a new power supply.  Is that possible?  I'm thinking more on the lines of that a chip went bad and the guy just assumed it was overheating and never had any concrete proof.  However, if i get the chip fixed, is there a chance it could overheat?  The board got pretty warm when i was playing it the other day, but, since this is my first game, i'm not sure how hot the boards normally get.  And is there supposed to be a fan inside? My cocktail game has a fan inside it, but my upright does not, could that be the problem?  Thanks for the input guys.

[fredster]

No, no fan in the uprights.  It wouldn't hurt to put one in it.

There are a lot of parts and chips on those old boards.  Next time it could be another one.  Remember, it's a 25 year old computer you have there.

You can buy a new jamma board and power supply with a jamma harness.

You can find those on rgvac.  The board costs $95, the power supply and th wiring harness are $25 and $12.50.

No problem.

Fixing the board will still cost you about $75, and it's good for a month.

[2PacMan]

Tell me more about this JAMMA thing.  What's the main difference between JAMMA and original.  If i get this board and power supply, will my monitor and coin doors and stuff still run OK??

Some people I see are really against Jamma, but is this the way to go?  I've been reading stuff about if you change your cabinet into a JAMMA cabinet then you can play all sorts of games on it, just unplug and plug them in...is it really that easy?

Also, are JAMMA boards emulations?  I guess, what i'm saying is that I want my Ms. Pac to be 100% original gameplay.  If i get this Jamma board, are the ghosts still gonna move in the exact same patterns, the colors and sounds will all be the same, or is it just a good emulation?...thanks

[fredster]

Jamma is a wiring thing.  It's all over the net. 

Your original board isn't Jamma compatiable without modifications.  Twobit com has a jamma adapter.

Your original has a unique wiring system with unique voltages.

And yes, your monitor and controls would be just fine.   You could just splice into it.

I suggest you start reading about it in the "wanna build a game" section of www.therealbobroberts.com.  Bob explains it in pretty good detail there.

[tbombaci]

Replace the ribbon cable on the daughter card. They get dried out  and make wierd things happen. It should run you about $10. I had the same problem in a cocktail that I sold. I went to service it and replacing the cable did the trick.

One way to test is to _carefully_ remove the Z-80 from the daughter card and pop it in the main PCB (remove the ribbon cable from the main PCB)

Your gamw qill come up as Pacman with odd looking characters (this wont hurt anything, it just looks odd) If the game plays fine for an extended period of time (however long you were testing previously), the ribbon cabe is likely the problem.

-Tom