Pacman PCB experts....HELP!

Zork2

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I have a sickly Pacman PCB that has a multitude of problems.....
First, the "character" and nicknames come up as all letters.
Second if you notice, there are two "dots" right below the "00" score. Also a dot below the power up pellet.
Third, at random times, there will be a red, sometimes red and green line through the "1up High score 2up" This usually goes away when Pacman eats the first power pellet on the demo mode.
Also at random times during demo mode, the screen flashes as if level was completed, and it starts the pacman being chased scene with full sound........
I have swapped the VRAM addresser board, and the Z-80 sync board with known good ones..... no change.
Also has new Z-80....no change....
Has anyone seen these issues before? Any places to start would be greatly appreciated!
Here are some pics
 

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I don't know about the other issues, but I believe there's a jumper trace that needs to be cut or jumpered to change the ghost names. Unfortunately, I don't know which does which...normal or alternate names. It's the same type of jumper that also enabled easy/hard mode. On Pac-Man, the alt names are just "AAAAA" "BBBBB", etc like what you're seeing.
 
The alternate name jumper pad is bridged. Its up above the dip switches. There is also a difficulty pad in the area.
Im not sure on the sprite issue, that would take some troubleshooting.
 
Thanks Riptor for the info,
Well the alternate name jumper pad was NOT bridged.... If fact the green protective masking was still in place. Just just for the heck of it, I bridged it. No change......
So I removed the bridge and I put a new DIP switch on, VIOLA, the name issue is SOLVED!!
Sigh, now for the other issues.......
What are some of the other websites that have repair logs on Pacman PCBs besides The Lawnmower man site? Hoping someone has seen this issue before.........
 
WELL PISS UP A ROPE! Turned the machine back on and the names are AAAAAA BBBBBB CCCCCC etc etc.....looks like more going on than I thought. Looks like something is shorting out the internal components of those DIPs????
 
Suppose it would have to be somewhere down stream of the DIP right?
 
What does self test indicate? I don't recall if it writes to every available space or not.

The socketed RAM is easy enough to swap but that probably won't clear your issue, I'd go poking around in the finish scratch pad RAM (those heat sinked chips in row 2 or 3 in cross row ABC&D).

Sorry, going from memory and it's been a hell of a day.....
 
I dont think the 2125 rams would be causing this. They mostly affect colors of the ghosts. You can swap out the 2114 rams or at minimum move them around and see if the symptoms change.
 
Self test indicated all is ok.......
I fired it up this morning before working on it. AAAA BBBBB CCCC DDDDDD
I swapped out all 2114s, with known good ones out of a good board.
Fired it up, all the names were THERE!
Cycled the game off and on, on the 4th time, names were AAAA BBBBB CCCC DDDDD

Put the originals back in, names were there, cycled the game off, and back on, AAAA BBBB etc.

Put the known good ones back in my good board, names were all ok......

Not sure what to think of all that....But I'm guessing that original DIP is fine.

Oh and the sprite issue never changed at any point.
 
What kind of shape are the VRAM and SYNCBUS sockets in? Are they missing the adaptors and have the fat square post forced into them?

Usually with logic you don't see failures coming and going like that, which might point out to something physical like a socket/component interface problem.
 
The sockets LOOK fine, and changing out the daughter boards with known good ones yields no change......
 
The sockets LOOK fine, and changing out the daughter boards with known good ones yields no change......
is this pac or ms pac? cause I thought that regular pac didnt have a daughter board or it came with something kinda like that but that it caused to many problems and people have always said to toss them I could be very wrong though
 
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It is a Pac Pcb, but it did have a "turbo" hack on it when I got it. On the CP it had had a "Turbo button".....it ran with a disconnect right to the PCB
Here is what the hack was.......
I am thinking maybe unsoldering one of these wires damaged the chip it was on.....
 

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Well,

If I had it up on the bench, the first thing I'd do is remove the hack and patch the PC board where they cut traces or patch where they cut pins on the chips...

Once that's done then the real troubleshooting can begin.
 
the first thing I'd do is remove the hack and patch the PC board where they cut traces or patch where they cut pins on the chips...
Yeah that was the first thing I did was to take the hack off.....
I didn't see any cut pins, or cut traces. Anyone familiar with this "turbo" hack? Maybe there is a trace or pin cut somewhere? A pretty stupid hack, you pressed the "turbo" button and the entire game sped up, ghosts, music and Pacman!
 
That hack just sped up the clock of the board. I dont remember if it required cut traces, dont see that hack very often.
 
That hack just sped up the clock of the board. I dont remember if it required cut traces, dont see that hack very often.

Yeah because it is totally POINTLESS! Ha! I'm going to try an work on this thing a few hours this weekend, I have a feeling maybe I damaged one of the chips taking off the wires?!
 
Got some chips on order for this board......
FYI I'm pretty sure its this hack expalined on the lawnmower man site...
"Little Black Box

This is a small rectangular black box about 2 inches long and a 1.5 wide with wires coming out of the top and connected to the pac man board in a few spots. I'm not sure who made this and I have seen home made versions of the same thing. I know one local (Central VA) technician that used the small plastic cup "ketcup containers" to build his own version of the little black box speedup.

Wire hookup for Little Black Box
•White - 5M pin 5
•Black - PCB ground
•Red - PCB +5 VDC
•Orange - 8C pin 11, lifted from the board (or cut trace)
•Green - 5S pin 12 (note 11, 10 etc could be used if a higher speed was desired)
•Brown - Push button switch on control panel or SPST switch to change speed when grounded."
 
Matt sent me the board and its all fixed now. Both sides of the solder pad were stuck low so I started poking around the buffer. Pin 14 of 8D was stuck low so I pulled it, stuck a socket on and replaced the chip. Problem was still there. Turned out the trace passed under the dip switch and it was shorted to one of the dip pins.
The board also had a couple stuck inputs which I found were caused by pulled traces under the buffer at 8F. Repaired the three traces and all is well again.
 
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