obtained pacman cab, not working. help!

[unix4hire]

While planning on my first cabinet I was very thankful that my brother gave me an upright original pacman cabinet!  However, like most things free, it does not work.

Before plugging it in I did some preliminary work.  I vacuumed out all the old spiders, dirt, nail clippings, cobwebs, etc.  I then checked all the fuses in the power supply base and looked over all the connections.  All looked good.

I noticed the main PCB has a daughter board coming out of it.  I looked up the part and found that the game had been converted to a ms. pacman with this daughter board.  However, the ribbon cable connecting the daugter to the main board was messed up.  I did some quick research and learned that where this ribbon plugs into the main board is where the original Z80 chip goes.  So, I removed the chip from the daughter board and placed it on the main board.  I also see that on the main board there are a couple of roms replaced with ms. pac roms.  I dont' know if this will affect whether the game works but I have no original roms to put back on it.

I then plugged it in.  Nothing.  Well, after a second there was a quiet high-pitched sound like you turned on an old monitor but there is no picture, no sound, nothing.  The high pitch went away after about 3 seconds and never returned.

I don't know what to do next.  I'd love to fix it back to its original condition and could find PCBs and such on ebay but my real worry is the monitor going bad.  But since I get no display or sound I don't knwo what to do next.

This site provided initial diagnosis info: http://users.erols.com/mowerman/pacfile.htm

Any ideas? 

[Witchboard]

Check your voltages coming from the power supply?

[Ken Layton]

Take the fuses out of the power supply assembly on the bottom of the cabinet one-by-one and check each one with an ohmmeter for continuity. Sometimes you'll have a fuse that looks physically good but may actually be blown. The ohmmeter will confirm this. Pacmans and Ms Pacs are well known for burning the foil traces on the gameboard edge connector and that can cause this problem.

[unix4hire]

I'll try out both suggestions.  I don't currently own an ohmmeter, any recommendations on a decent (but not expensive) model to buy?  I've wanted to buy one anyway so this helps justify it.  thx!

Also, I've heard you can just replace the original PS with a simple computer case PS.  Anyone have a link on instructions to do this? ---Erich

[Ken Layton]

Converting a Pacman to a different power supply is pretty involved for a newbie to do. Not only does it involve mounting and wiring a modern switching style (screw terminal, NOT computer style) power supply, but you also need to make hardware modifications to the game board. If you're not experienced in circuit board repair/rework you should not attempt it.

[RayB]

Ummm, I think you should put the Z80 back to where it was and then fix up the ribbon cable so it's connected properly...

Then check voltages and other connections...

Also when you check the fuses, look for rust on the fuse clips. If there is any, that can impede proper contact with the fuses...

[unix4hire]

What should happen if the power is fine but the board has problems (ICs, pins, whatever)?  Will the monitor light up with just no display but a glow, will there be any sound?  i.e., if I were to disconnect the PCB entirely what should happen on a known good machine if it is plugged in?  Trying to get a feel for what should happen depending on what the problem is.

ALternatively, my friend has a frogger with a bad monitor (sound works and such).  Could I take the pac PCB and plug it into frogger to verify if the PCB works?  (will get ribbon cable fixed also)

[RayB]

What should happen if the power is fine but the board has problems (ICs, pins, whatever)?

[unix4hire]

Boy do I feel like a newbie.  Apparently the power supply works fine, it helps greatly if you turn it on!  I had to pull out the switch on the backside of the cabinet that prevents power while the back panel is removed.  Now it fires up fine!

The monitor appears to work great.  Of course, the game doesn't work.  I get all sorts of lines and other characters on the screen and no movement.  I sitll have to replace that ribbon cable between the daughter board and the main board.  After that I'll have to consider a new PCB if it doesn't work.

[Ken Layton]

You can send your gameboard out to either Two Bit Score (www.twobit.com) or El Dorado Games (www.eldoradogames.com) for repair.

[unix4hire]

Thanks for the link, Ken.  The first one looks especially good since they don't charge to do a diagnosis (or to ship it back!).

Here's a pic of what the screen looks like after turning it on.  If anyone has seen this please give me some hints to what it might be.  thx
note: image is rotated from actual upright screen

[SirPeale]

Someone posted in RGVAC not long ago a HUGE page full of Pac problems, AND their fixes.  Let me see if I can dig it up.

Edit: not the site I was looking for, but it's a start:

http://www.mikesarcade.com/arcade/pacfix.html

The right one when I can find it.

Another:

http://users.erols.com/mowerman/pacfile.htm

Edit again: Found It!

http://www.arcadegameover.com/troubleshoot/pactrouble1.html

[Searcher7]

I'd recommend Richard Cross: "Rx" <rcross@tbaytel.net> if repairs to your PCB are needed.

He repaired six of my Pac-PCBs last year.

Darren

[unix4hire]

I'd recommend Richard Cross: "Rx" <rcross@tbaytel.net> if repairs to your PCB are needed.

He repaired six of my Pac-PCBs last year.

Darren

How much (range) did it cost you per board?  I see this "repair" kit two-bits has for sale on ebay for $49 that looks decent but doesn't guarantee it'll fix my problem.

Also, after comparing to various pics on the web I seem to be missing a (potentially) very important mini-board; I believe it to be the sync buss controller board that sits in a socket on the main board.  I see one on ebay for $25 but wonder if I can find it elsewhere cheaper... I'll keep looking.

[Searcher7]

How much (range) did it cost you per board?

[RayB]

Before shipping out a board for repair.....

1. Make sure all chips are properly "seated" in their sockets...and all cables or harness are snug.
1B. Look for broken pins on any chips, capacitors, etc...

2. Clean the edge connector with a pink eraser... to make sure the harness makes good contact with the edge traces.

3. Measure the voltages. If the board is not quite receiving enough power, it could result in problems like you see above. Or if you do self-test, it could report RAM/ROM errors...  (I've even heard in some rare cases that using too long of an extension cord can be a problem (like a 40' outdoor extension cord))

Does the cabinet have a switch to turn on "self-test"?

[unix4hire]

It's me again.  Good and bad news.  Pac is mostly restored!  Board has been repaired per two-bits, cord replaced, monitor swapped with another.  Game was working great last night for about 3 hours.  Then out of no where the characters started weirding out and some lettering on top/bottom is  missing.  Nothing exactly matching in any of the pictures on the sites listed above.  Simple character rom or something more serious?

[Ken Layton]

Judging by the odd high score coloring and apparently missing letters there I'd say you should check the warranty on the Two Bit repair and send the board back for repair.

[RayB]

Ken, could there be a voltage problem which is simply just "re-damaging" the repairs?

[SuperGunGuru]

Just wanted to mention another board repair guy named Alex Yeckley. He's awesome at what he does and is very reasonable on price. Check out his website www.elektronforge.com

[bjk7382]

monitor swapped with another.

[unix4hire]

I swapped the monitor because the original would flicker and shut off, then come back on intermittently (game continued to play).  I found a similar model monitor in a used machine at auction.  In a previous post Ken said the two models would be interchangeable and the connectors certainly were, so I swapped 'em.  Because it seemed to work great initially I don't think there is a problem with the connection.

But there may in fact be an issue with voltage at the board connection.  I've emailed twobits the pics and asked them what they thought, haven't heard back yet.

I'm very new to this so I have yet to learn all the troubleshooting steps when somethign is awry (crap, still need to buy a multimeter).  I'm trying to save up to buy some randy fromm DVDs which I hope will help me out a bit.

[unix4hire]

Well, twobits said they'd be happy to "look at" my board if I'd send it back to them, and it's common for boards to go bad if not in use for 3 months at a time (I find that extremely hard to believe, especially after they "fixed" it!).  So I think I'll try a few other things first.

So, I see a character eprom set on ebay including 6 proms for row 6 and 3 for the daughter board.  However, my board has no proms on row 6 in indicated slots and never has (as far as I know).  So, how can it have worked without these proms, or where could they be located instead?  maybe combined with other proms elsewhere?  thx

[RayB]

Well, twobits said they'd be happy to "look at" my board if I'd send it back to them, and it's common for boards to go bad if not in use for 3 months at a time (I find that extremely hard to believe, especially after they "fixed" it!).

[CheffoJeffo]

Why don't you follow Ken's advice (posted July 17)? The longer you wait, the less likely TwoBits will fix the board again for free. Do it now while it's still under warranty.

The last thing you should be doing is "trying things" like buying and installing chips. Is sending the board back to TwoBits for a free warranty repair really worse than SPENDING MONEY ON PARTS FROM EBAY?!

Absolutely ... don't sit on it and fiddle ... get the board back to twobits !!

Cheers.

[unix4hire]

You don't understand, there is no warranty provided from twobits.  The warranty was only if I bought a new board from them.  And the board did work the first time I tried it when I received it from them.  I then turned it off, restored the cabinet, and put it back together.  It worked yet again for a few hours and now acts weird.

Twobits is not offering me a warranty on my own board.  They say they will inspect it and tell me what's wrong for free but then I'm still out the $20 to ship it to them.  The work was done in March.  I didn't have the problem until last month (despite it not operating for the prior 4 months).

[CheffoJeffo]

OK, then I guess my first question is ... since you've got the board back and working, then not working, have you put the game in TEST ... if so, what were the results ?

Then, have you been through the board troubleshooting guide ?

Cheers.

[unix4hire]

I did run the complete test scenarios that come with the twobits daughter board + chip.  THey all worked great except the character  screen which produced the same weird characters I see during regular gameplay.  I haven't run the game itself in test mode, I'll check that out.

I do'nt think I have that board troubleshooting guide, I'll see if I can download it.  thx

I still wonder why I dont' need chips in row 6...

[CheffoJeffo]

I do'nt think I have that board troubleshooting guide, I'll see if I can download it.  thx

http://www.arcadedocs.com/vidmanuals/P/Pacman-Troubleshooting-Guide-Part1.pdf

[SuperGunGuru]

You don't understand, there is no warranty provided from twobits.

[RayB]

OK sorry for the misunderstanding.
You really should run it in test mode. It will report any bad chips and tell you exactly which one(s).

Then make sure all chips, the daughter card, etc, everything is very snugly connected. Actually, you can even do this now before running in test mode.