Ms.Pac-man Cabinet: No Picture on Monitor

D_Harris

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I had to test a Pac-man Plus PCB in a Ms.Pac-man cabinet that is dirty but all original.

But I get nothing but horizontal streaks on the monitor that start from the top and get dimmer from one to the next going down. They are about one inch apart.

There is no movement or sound whatsoever.

I tried plugging in a Pac-man with the same results so obviously it is not a game board problem.

I tested and cleaned the fuses, but was wondering what the chances are that the problem is the (original)fuse holders or a transformer.

I did plug in a non-working Jr.Pac-man PCB that I know only displays random characters all over the screen. It did display this, but then when I swapped it out and back in I came up with the dim horizontal bars that I was getting with the other PCBs.

Any ideas on where to start? (I'm just hoping it is not a monitor problem).

Thanks a lot.

Darren Harris
Staten Island, New York.
 

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The cabinet is in an awkward position and there is a great deal of black dust that has obviously been accumulating since the game came off the assembly line, so I wouldn't even know which of those buttons is for brightness. But like I mentioned for one PCB 5 second swap everything was okay, but then it went back to what you see in the pic.

And yes it is a 4900.

Thanks.

Darren Harris
Staten Island, New York.
 
Well, I figured I'd wait to see if the cause of the problem was actually the monitor itself. :wink:

(Which it actually doesn't seem to be).

Darren Harris
Staten Island, New York
 
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It might be the monitor. I asked if this was a 4900 because I worked on a Super Pac cab a few years back and it had those lines on it. I never got to work on the monitor because higher priority projects came up, but I distinctly remember those lines.

Has the monitor been capped? If not, start there.
 
It might be the monitor. I asked if this was a 4900 because I worked on a Super Pac cab a few years back and it had those lines on it. I never got to work on the monitor because higher priority projects came up, but I distinctly remember those lines.

Has the monitor been capped? If not, start there.

But you never actually got a chance to fix that game?

I just tried another game board.(A known working Ms.Pac-man PCB). I receive the exact same results.

There is no audio from coin-up or game play, and no movement on the screen from coin-up or game play.(There is only a faint hum when the game is on).

Though it worked for a 5 second swap yesterday, it went back to those frozen lines and I can't get it to work again.

Anyway, it seems like you're saying that a monitor problem can cause a game PCB to not work at all.

Ok, I'll post this in the monitor section.

Thanks a lot.

Darren Harris
Staten Island, New York.
 
Common sense tells you... If you have a known good board and nothing comes up your problem is the power supply. The monitor may have issues too. You obviously need to have it playing blind, unless you are going to pull the monitor and test it in another cab to see if it works.
 
Well, I'm still looking for ideas on what to do next. Does anyone have a link for info on testing and repairing linear power supplies?

Or should I post this question back in the "General Repair And Help" section?

(I had re-posted this before I knew this original thread was moved here).

Thanks.

Darren Harris
Staten Island, New York
 
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I would pull the monitor and test it with a known good working game.

The power supply testing can be done by reading the voltages off of the scat and testing them. Example: Pull the fan connector apart and check for 120vac. or Pull the monitor connector apart and test for 120vac. or Pull the edge connector and check the appropriate pins for 7vac. etc.
 
But you never actually got a chance to fix that game?

Anyway, it seems like you're saying that a monitor problem can cause a game PCB to not work at all.

I fixed the Super Pac part, but never got around to the monitor.

What I'm saying is that Super Pac had those exact lines on it, and they clearly don't belong there.

Agree with Dokert. Have you done the basic troubleshooting, eg checking voltages, testing fuses, etc?
 
I fixed the Super Pac part, but never got around to the monitor.

What I'm saying is that Super Pac had those exact lines on it, and they clearly don't belong there.

Agree with Dokert. Have you done the basic troubleshooting, eg checking voltages, testing fuses, etc?

I'd have to figure out if I can hook the monitor up to my Super Gun or add a harness to my other Ms.Pac-man cabinet which is in transition.

Yes, I did the basic checks. As I mentioned the fuses are good. Unfortunately, the voltages are not looking too good. They seem to be inconsistent and wrong...

These some of the voltages I was getting from +5V pins:
"C" = +7V
"D" = +8V
"E" = +.99

And these were the +12V pins:
"W" = +9V
"X" = +8V

I decided that the best option is to take out the big transformer and put in a switcher.(And if I am lucky enough to find a 22/44 edge connector I'll change that also).

Thanks.

Darren Harris
Staten Island, New York.
 
Bob Roberts has 22/44 connectors readily available. You WILL still need an isolation transformer, and Bob has those too.

Yes I know. But I should have some around here some place. And I'll just leave the original iso in the cabinet and use that.

Thanks.

Darren Harris
Staten Island, New York
 
After taking out the big transformer I tested 1/2 dozen switching power supplies with several different game boards and for some reason I can get consistency, except if I test at the power supplies themselves.

More importantly I can't get any where close to +12V with any of the PCBs when using the test points just under the edge connector. Sometimes I get hardly any reading at all.

I cleaned the harness and made sure the pins in the edge connector weren't flattened, but I was wondering if the ISO transformer can cause a problem like this.

I guess I'll have to try a completely different monitor tomorrow. But the only ones I have available here that were known working are the Sanyo 20EZs.(I also have a dirty 4600 that may or may not work).

Thanks.

Darren Harris
Staten Island, New York.
 
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