Jr. Pac-Man (in Mappy Cab) pcb issue

Reddogg

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Hey KLOVers, wondering if someone might have some insight into the problem I'm having with my Jr. Pac pcb in a Mappy cabinet. All the power and wiring is original, and the filter is still hooked up to the game pcb, and all voltages going thru the wiring harness check out.

But what happens is that there is a buzzing sound thru the speaker, and also a yellow dotted vertical column that scrolls across the screen from right to left. The width of the column also seems to start thin and grow wider as time passes. The game will play, and the game sounds can be heard, and the monitor works fine (I already capped that).

But the game will also freeze a lot of the times after a few minutes, but sometimes as quickly as 10-15 seconds.

I'm assuming there's a power issue of some sort on the pcb, since it powers on, boots up, and will play, but then freezes, and because of the buzzing sound. It also went into a rebooting fit one time when I turned it on. But I have no idea where to look, and the manual doesn't seem to help much either.

Thanks for any help!

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How are your voltages? I assume you get none of these issues with the Mappy PCB?
 
My voltages check out, but I don't have a Mappy board. It was converted to Jr.

I sent the Jr. pcb to Riptor to see what he can do.
 
Start by throwing the filter in the trash

Cant do that with a dedicated JR, you need the filter board. Its been a long time since I looked at mine but if I recall correctly its not pinned straight through. It also has the power connectors on the filter board....same setup as galaga but its not on the game pcb.
 
Cant do that with a dedicated JR, you need the filter board. Its been a long time since I looked at mine but if I recall correctly its not pinned straight through. It also has the power connectors on the filter board....same setup as galaga but its not on the game pcb.

That sucks ass
 
Well, I got the board back, and installed it, but I still have all of the same problems except the humming thru the speaker, and the sound didn't work at first. I had to crank it all the way to get it to kick in.

I actually got an entire screen of the yellow dots this time, and once they disappeared, an extreme horizontal wave from right to left (technically vertical from the bottom up), followed by a board reset.

So, now I'm thinking the problem is either my power chassis, or the power supply board.

Any idea where I should look first?

When I measured my voltages thru the harness at the edge connector, all checked out.

Thanks.
 
On second thought, scratch my last post.

I just took measurements again, and they're funky. Without load (no board), I'm getting fluctuations from 9.39VDC to 9.49VDC at pins 6 and F of the edge connector (attaches to filter pcb). At J2 of the filter pcb, I'm getting 9.38VDC at pin 3, and fluctuations from 15.47VDC to 15.10 VDC at pin 1.

I tried adjusting VR100, VR101, and VR102 on the power supply board, and re-measured, but there was no change in voltages.

I have no expertise in this area. Anyone who knows what they're talking about want to clue me in?

Thanks.
 
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Whoops! Those are VDC.

I went back and checked and I was plugged in to the VDC on my DMM. Those readings are what I got VDC. Sorry...I'm stupid!

I did replace the pins in the edge connector where I got the readings. After, I was able to play for about 7 or 8 mins, got to the 4th Jr. maze, without any yellow dots, but then out of nowhere it began resetting. I turned it off, and now I can't get the Jr. pcb to boot up (not even playing blind).

I remeasured, and now at pin 6 and F on the edge connector I'm getting 6.02. And at J2 on the filter I'm getting 6.02 at pin 3, and 15.76 at pin 1.

So, the edge connector voltage dropped almost 3.5, and now the board won't boot.

I'm not too sure about what I'm seeing in the manual. Can anyone tell me which voltages need to be present, and where, for the board to boot?

My voltages are also fluctuating (each time I take them they're different). They don't change by much, but is that even okay?
 
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Check your voltage on the power supply and see what you get. You either have a flaking power supply or some connection issues from it to the board.
 
im curious as what your +5 volts is
ON
the game board

seems like almost there is a short somewhere making the game act funny
 
Okay...just took a bunch of measurements to try and fix this thing before I leave town for 3 weeks.

Here's what I'm getting now:

At pins 6 and F on the edge connector (one that attaches to filter), and at J2 pin 3, I'm getting 5.47 VDC without a load. With a load they all measure about 1.60VDC. So, it seems as if my filter is getting more than the required +5VDC.

I also took measurements where the filter connects to the Jr. Pac pcb, and nothing reads when not hooked up to the Jr. Pac pcb, so I measured on the Pac pcb itself while under load, and at 6 and F the voltage starts at around 6.50 and steadily keeps climbing until it almost stops at around 7.33. Seems strange to me, but still more than the required +5VDC. Or is it converted or something at this point to AC?

I'm going to replace the edge connector asap, but how does one change the pins on the filter pcb (where it connects to the Jr. pcb)? It's not the same kind of connector, but they are similar pins.

I tried to take measurements from the power supply, but I'm not sure which pin to use as ground while measuring. And should I be measuring for AC or DC there? Ugh...
 
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