Ms pacman not working..please help

[GMZombie]

I have a Ms pacman board that was working till I moved and afterwards it only shows this. The pic is a bit dirty but it just shows garbage on the screen blinking. The board itself has the speedup rom and Ms pac attack roms. Anything I should be looking at first?

[CheffoJeffo]

Check connections and voltages before going to the board.

[DeLuSioNal29]

Yeah, sounds like something got jarred loose in the move.  I would do what Cheffo says and check the harness connections and voltages of the PSU.  Next I'd move onto re-seating the daughter board, then check the IC chips themselves.

Good luck!

D

[paigeoliver]

Ms Pac makes its own power on the board, it doesn't really have a power supply.

I would reseat the edge connector and all the socketed chips.

[jennifer]

   I would only reseat those chips as a very last resort as those legs are very fragile, The  edge connector to the board is where Jennifer would look first,  The connector traces on the board are problematic on those and they tend to burn, and or just wear out,  moving the game can very easily make it lose contact.

[mrclean]

I have a Ms pacman board that was working till I moved and afterwards it only shows this. The pic is a bit dirty but it just shows garbage on the screen blinking. The board itself has the speedup rom and Ms pac attack roms. Anything I should be looking at first?

Ms. Pac-Man doesn't like to get jiggled... it makes her wavy.

Firstly do you have an original linear power supply or is it a switching power supply with an adapter ? If the machine was moved typically it's something really simple like a lose wire connection. Could be a multitude of issues but for simple starters you may need to reseat 5E or 5F on the logic board. Did the daughter board (smaller board) get disconnected from the main board ? Make sure the power is off, and unplug the main wire harness, re-secure it, along with anything else that's easy to do. Also I know this sounds stupid but can you test it with another spare / backup board that uses the same pinout ? Typically I like to try fix issues based on process of elimination.

[GMZombie]

i have tried to reseat everything. re seated the edge connector too. the power supply is a newer jamma power supply i can get pics of that as well.

[mrclean]

i have tried to reseat everything. re seated the edge connector too. the power supply is a newer jamma power supply i can get pics of that as well.

OK so you have a switching power supply, sometimes they have adapters, is it flush ... everything properly screwed into the terminals ? Is the adapter / game board as well again the daughter board all snug ? getting the proper voltages ? can you test with a multi-meter (pref. a fluke hehe) ?  Again do you have a Pac-Man board or anything with the same pinouts to test that it's the board and not anything else.... process of elimination !

& I'm not saying you did, but i've even done it in the past where I thought I properly re-seatted chips and a leg wasn't in the slot, verify 5E & 5F specifically again.

[GMZombie]

Unfortunately I do not have a backup board or one with same pinouts. I'll check the voltages comingbfrom the Power supply. I originally did the power supply swap myself but bit has been St least 5 years since I did that so I forgot lol

It appears after checking voltage on a rom chip at pin 12 and 24 I do not have the correct voltage. From what I read I'm supposed to have 5 volts at a rom chip and I do not. I started looking at the ac to DC converter on the board and at d9 I have a diode that doesn't check out. My reading on it is a .076 and most diodes should read between .4x and .7x at most. I also was reading that with the switching power supply it is not needed to have the ac to DC converter on the board active anymore .

[jennifer]

  You need to do more than reseat that edge connector, wiggle it with the power on....Fwiw, Jennifers Fluke is Junk, all wore out and spastic, Loved it while it worked but not really excited about replacing it, and rather than write the big check I have  been using my Voltohmist senior, OMG, so retro

[GMZombie]

Yea that didn't help. Like I said I don't believe something is passing enough voltage as any rom chip doesn't have the needed 4-5vdc on the 12 and 24 pins

[mrclean]

Yea that didn't help. Like I said I don't believe something is passing enough voltage as any rom chip doesn't have the needed 4-5vdc on the 12 and 24 pins

This happened to me on my missile command... as crazy as it sounds I was getting drop off because of the pin inside the wire harness, I popped out each individual pin and sanded them so it would make a better contact and fixed the problem.

[paigeoliver]

I don't like seeing the Pac games running on a switcher because you never know if it was done right unless you did it yourself.. Better to just get the power section of the board working right in the first place.

[behrmr]

Maybe you've done it and just didn't say it. But post #2 is where to start with CheffoJeffo's recommendation.  What is the voltage at your switcher power supply lugs?  What is the voltage at the edge connector of the PCB?  Have you tested the voltage regulator on the PCB itself?  If those check out to be slightly above 5V and your ROM's are getting basically zero volts, and your edge connector is clean, and making good contact with the harness, then I would guess the power supply on the PCB is not working, particularly caps and the voltage regulator.  Look for bulging or leaking caps. If the voltages to the edge are bad it may be as simple as a faulty switching power supply.  Take a look here for troubleshooting steps at the POWER SUPPLY section and see if that helps.  http://lawnmowerman.rotheblog.com/   Get your power issue sorted out before you do anything else.  Cleaning and reseating chips on one of these PCB's can lead to a lot of broken legs so be gentle if you have to go there.  Also make sure your NVRAM and SyncBus cards are properly seated and secure.

[GMZombie]

Yea with a switching power supply I have the volts cranked up as specified to 6 volts on the 5 volt and the 12v went up to 26v but from what I understand the board drops the volts down and I think I have found a problematic diode in d9. That diode came up on my multimeter as a .029 which isn't good at all. The voltages coming from the power supply is working and good.

[behrmr]

You can always do the dc hack and remove all of that.


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[jennifer]

    Seeing how it worked before you moved it, The odds of component failure in my mind is (although possible) not really a common problem.... I would do another test point between the switcher and that diode before you start tearing it apart.