Ms. Pacman Cocktail Trouble - Blue Screen, No sound or game

[ArcadeClassix]

Hello all!

I just picked up a Ms. Pacman cocktail for next to nothing. When plugged up it lights up, fan runs, and the monitor is completely blue.

Things I have done to troubleshoot thus far are

1. Check all wires and grounds
2. unplug and replug all connectors

Things I have found that were wrong and I've corrected are

1. The yellow ground strap had came off the "daughter board" coming off the top of the main PCB so I screwed it back
2. The dip switch settings were all wrong including switches 7 and 8. I put them to the correct settings.
3. I looked at chip 3B on the board per the arcadegameover.com picture problem analysis and it looks to be fine. (3B is not a socketed chip from what I gather).
4. The ribbon cable that goes from the original Z80 socket to the Ms. Pacman rom board had broken legs on it so I removed it and tried booting it that way to see if it would maybe read an error screen instead of just going to the vlue screen but no luck there.

So that's where I am at for the time being. I am looking for a ribbon cable so if someone has one or can direct me to the best place to get one, I'd appreciate it. PM me. Thanks in advance for all your help. I'm ready to play some Ms. Pacman!!

[SirPeale]

Did you put the Z80 back in that socket you removed the ribbon cable from?

[ArcadeClassix]

I'm guessing I don't have a Z80 since I have the ribbon cable that replaces it and goes to the Ms. Pacman rom board? Or is there another one on the Ms. Pacman board? I'm bout to pull the board and shoot some pics after I try putting my ribbon cable on it from my upright I have in storage to see if that changes anything.

**ALSO, wouldn't I at least see some sort of error screen on the monitor if the rom board wasn't connected instead of just a blue screen?

[RayB]

**ALSO, wouldn't I at least see some sort of error screen on the monitor if the rom board wasn't connected instead of just a blue screen?

Z80 is a CPU so no, you wouldn't get errors. You'd get nothing.

[SirPeale]

Yikes...it's been a while since I worked on a MS Pac board.  It's identical to the Pac-Man board except for the daughtercard.  

I had to pull up a photo to refresh my memory:

http://coinoparcade.com/pcbs/Bally%20Ms%20Pac%20Man%20PCB.jpg

Where the CPU would be on a Pac-Man board is where the Ms Pac daughtercard plugs in.  The Z80 is on that daughtercard.  Make sure you plug it in the right way.  BE CAREFUL REMOVING IT, AND PLUGGING IT IN.  You don't want to bend any legs!

Also, you need a CPU to see errors of any kind.



edit: RayB beat me to it!

[SirPeale]

You also might have monitor issues.  I'd like to see photos of the BACK of the monitor, as well as whatever appears on screen.

Have you checked any of the fuses yet?

[ArcadeClassix]

I looked at all the fuses and they look good. The thing wouldn't power up at all if the fuses were blown no? I have a fuse kit handy though.

I don't think it's a monitor issue, at least at this point, because the game doesn't make sounds otherwise to make me think the monitor is out.

I need a tool to get the Z80 out of my daughtercard, but I don't have the tool. Any redneck way of getting it out relatively safely?

At this point, I need a ribbon cable for sure because both of mine are trash.

[SirPeale]

You can use a jewelers screwdriver.  Place it GENTLY under one end of the chip, and lever up.  Repeat on the other side.  Just make sure it's the CHIP and not the SOCKET.

You may need a point of leverage.  I like to use a pen or pencil.  Just lay it on the board and use that as the fulcrum (I think that's the right word).

Your best bet is to get your game to work as regular Pac-Man first, then move it to Ms Pac.  Ribbon cable may be bad - but it's not needed for Pac-Man.

[SirPeale]

As for the fuses, you can't just look at them to determine if they're bad or not.  You need to use a multimeter.  Fuses, particularly slo-blo ones, can LOOK good when they're not.

Or just look closer.  You may have to clean the glass on them to see inside them.  If they're blown you can probably see some of the strands separated.  They don't always blow "black".

There are seven fuses on a Pac cocktail.  Four of them are for the PCB, two for the monitor...I forget what the last is for.  Check them all carefully.

[ArcadeClassix]

Just plugged in the Z80 from the daughtercard into the main PCB, no difference. I'm going to try replacing the fuses, then I'll pull the board if all else fails and take pics.

**Took the boards out and chip at 3D had corrosion, or what looked like it, at one leg. I am swapping it with one from my other board and see if that does anything.

**Also, I took the "pacman filter" that goes on top of the main pcb off and hooked the wire harness directly to the board. I got a humming sound out of it. DUnno if that's good or bad...

[CheffoJeffo]

I'm with Peale ... sorry SirPeale ... and would want to see some pics and you need a multimeter.

Have you adjusted to RGB controls on the monitor to see if you can change the colour ?

And, I don't think so from reading this thread, but I need to ask to be sure -- she's not playing blind blue, is she ?

[ArcadeClassix]

She's not playing blue. I'm going to change the fuses since I got some and if that doesn't work, it's off to Two Bits for analysis. I live 4 hours or so from there so shipping and turn around should be pretty quick. I may build a replacement cab for it in the meanwhile restoring everything as I go. Some smart guy took all leg levelers out so the thing sits on the sides... you can imagine the rest.

I'll get pics in a couple of hours.

[RayB]

She's not playing blue. I'm going to change the fuses since I got some and if that doesn't work, it's off to Two Bits for analysis. I live 4 hours or so from there so shipping and turn around should be pretty quick.

... if that's the kind of money you want to waste....

[ArcadeClassix]

... if that's the kind of money you want to waste....

Is there something I should know? I just sent my boards off...

[SirPeale]

Yeah...they're really expensive.  And they get pissy if you decide to not have them repair your stuff.

[ArcadeClassix]

My boards are beautiful lol. I'm not spending a lot to fix them they shouldn't need much. You guys can be the judge though. Here's detailed pics of the boards - http://pbckt.com/s9.XZU

[ArcadeClassix]

Here's the cost of my repairs from twobits.com -

74xx chip  $5
skt $2
2114 RAM $9
ribbon cable N/C
1 Hour $90.
total $116.00

It was over $200 but that was including the suggested ABC repair kit. He didn't bother testing my rom board since my PCB didn't boot. I thought that was dumb considering he probably has a test machine he could try out my rom board on to see if it was good. Not a pleasant experience for the money so far...

It was like pulling teeth getting them to email me what all needed done to my board prior to them doing the work too. strange...

[ArcadeClassix]

Sorry to bump my own thread but I put the boards in after I got them back from twobits yesterday and voila! Working Ms. Pacman!

Initially there was no sound, so I tried changing the speaker, no dice. I then took out the filter board on top of the main PCB and got working sound.

I do still have some monitor adjustment to do, the picture extends vertically and i can't see the high score at the top. Is there an adjustment for that?

Once this thing is solid mechanically, I will be starting a build thread  because I have all new parts on their way!

[CheffoJeffo]

I'm glad it all worked out.

You may need to adjust the horizontal width coil to bring the picture into line (it's not as easy as typical adjustment). My advice is to not use a metal tool to make the adjustment.

[ArcadeClassix]

Thanks CheffoJeffo,

I guess I have one of the smaller width coils because I didn't spot it on an initial looking around the monitor/chassis. I read about not using an allen wrench, I might have to do some african engineering... 

[SirPeale]

Or the top has broken off.  Then it would just look like a coil of wire sitting on there.

[ArcadeClassix]

Found it lol. Which way should I have to adjust it to get the picture shorter? Clockwise or counterclockwise?

[SirPeale]

Try counter.  If that doesn't work, go the other way.

[RayB]

If it's a G07 there's also those 3 alignment tabs he can move the wire among...

[ArcadeClassix]

It's a Wells Garner, I'll get the model number tomorrow. Made restoration progress today, redid the top top and adjoining piece. I'll post in restorations tomorrow.