Search results for query: *

I had one that did that. it was a problem with the vram addresser sub board. At least it was something similar. The bottom half of the screen was duplicated on the top half of the screen but the scores showed correctly.

I am glad that was your problem. Fixing it will be easy.

Woohoo! You can get a ribbon cable off of eBay or probably twistedquarter.com. there should be several other suppliers that have it is well. In the meantime, you can play some Pac-Man with slightly messed up characters if that doesn't bother you. At least you know that your board does work.

I noticed that that black wire is connected to the backside of the CPU socket on the mainboard. Check the back side of the daughter board and see if it may have been attached to the socket where the ribbon cable plugs in. This wire may have been used to bypass a bad connection on the ribbon...

Which ones are those?

Messed with 3F and 3H. Background is good now but movement is messed up. https://youtu.be/ZolDHVKXm0I

It's doing better than it was. I have already fixed three problems. The Edge connector was bad. The7474 at 8C had a pin cut and then re-soldered. Two of the ribbon cable pins were broken off. At least the board is actually running now. Unfortunately I do not know what specific chips to look...

Very bad video problems here. Board runs and plays. the moving characters are fine Nothing else is. I have seen these do a lot of weird things but never this. I have tried row 4 Ram to no avail. The daughter board and ribbon cable are not the problem. Neither are the row 6 ROM chips...

It looks like you got all the basics covered. There's an electrolytic capacitor on the left side of the PCB about halfway down. That is a good place to check the 5V. what do you get across that capacitor? If that is normal then It's probably down to an actual failed component now.

Yes dip 8 freezes the video. If the game is powered on with that switch turned on it will look as though there is something wrong with the machine. With the ribbon cable eliminated as a problem if you have an extra z80 processor or another board that uses a z80, you may want to try that next...

Thank you everyone for your help. I've been so stoked about getting this game running properly. I swapped the wires and it works great now. I'm going to have a little chat with my seller about not mentioning that. Now all I have to do is replace the big blue cap, get the monitor dialed in, clean...

That's where I was.

Thank you I found the Bob page. I will go downstairs later and bang my head on that for a while. Right now I'm watching a rush concert from 23 years ago.

I just got brand new trackballs for my centipede cocktail table and they don't work exactly right. On both, one axis is fine and the other one is backwards. Up and down are okay but left is right and right is left. It makes playing the game very difficult. I got these things from someone who...

Remove the ribbon cable and transplant the Z80 CPU from the daughter board on to the main board. If a game now boots as Pac-Man with messed up characters then you have a bad ribbon cable. See my response to your original post for more suggestions.

If it plays with sounds, you may be missing your -5V. I had that with a JAMMA adapted DK3 PCB once where the -5V was not connected in the cabinet. That is exactly what it did. Once the -5V was hooked up, it worked fine.

The test switch does not make a difference. I will try removing the Pokey chip after work to see if that makes a difference. The Other Board is missing one of the 40 pin chips but I don't know if its the CPU or the Pokey. What do you charge to repair these boards? Is it a flat rate or does it...

No the crystal does not seem to be loose. At one point the screen was completely Orange. That was the only time it was different from the blank raster.

I removed the go7 FBO from the centipede cocktail and plugged it into my ms.pacman and here is proof positive that there's nothing wrong with it.

I plugged my Pac-Man test rig into the monitor and got video. My game has no start buttons and the ones I do have are in bad shape. Not excited about hooking them up. I did coin it but got no sound. Pede does have a coin up sound, right?