PacMan Resetting

jeff412

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I've searched all of the troubleshooting websites and I can't find my exact problem. I've got good voltage. The game constantly resets before going into attract mode. Occasionally, (very rarely) it will go to attract mode, then when I try to coin up, it will reset. I reseated everything. Replaced all the ROM's. I resoldered 8B and 9C. Haven't replaced those yet. I guess it's worth a try, but I wanted to see if anyone here had this problem. I saw where Dockert had a similar problem, but there was no solution posted.

Thanks,
Jeff
 
I can't find a wiring diagram of Pacman, but do they have a tilt switch inline with the test switch similar to Galaga and Ms.Pacman? If that's shorting out it could cause resets.

The pinout's i'm finding online shows a reset switch on connection #6, no idea how/if that's wired in but could also be worth tracing.

-Hans
 
I have also seen this happen with Pac/MsPac due to bad fuse blocks and attendant connectors and dirty/worn out edge connector.

Replace the fuse blocks and re-terminate the QD connectors and clean or replace the fuses.

Thoroughly clean the PCB fingers and edge connector, or better yet replace the edge connector entirely with a new one and new crimped pins. Pac and similar Bally games of that era are notorious for the edge connectors going loose/bad.

They take a 22/44 connector, I think.

RussM
 
I've got a new connector. I haven't installed it yet. I don't have a crimper that works worth a flip with it. I will check the fuses. I know they are all good, but I'll clean up the connections and see if that makes a differnce. However, I do have good voltage at the connector.

Jeff
 
I had a simular problem took my board to riptor for repair turned out to be a bad Z80 put in a new one and problem solved
 
I also tried a new z80B. It didn't fix the problem. It actually seemed to get worse. Perhaps the new processor was bad too. I'll try another one just to be sure. Can someone verify that the z80B is backward compatible to the z80? I believe they are.

Jeff
 
I also tried a new z80B. It didn't fix the problem. It actually seemed to get worse. Perhaps the new processor was bad too. I'll try another one just to be sure. Can someone verify that the z80B is backward compatible to the z80? I believe they are.

Jeff

Yes, they are. Maybe it's the Z80 socket.

Edward
 
Boy did I screw up. I desoldered the cpu socket and when I pull it out I pulled up about 8 of the traces on the top side of the board. Now I've got to go back and patch all of that. Ughh! All of the legs appeared to be free from solder, but evidently there was still some on the top side. I wouldn't have been able to see it because every trace I broke was under the socket.

Jeff
 
Boy did I screw up. I desoldered the cpu socket and when I pull it out I pulled up about 8 of the traces on the top side of the board. Now I've got to go back and patch all of that. Ughh! All of the legs appeared to be free from solder, but evidently there was still some on the top side. I wouldn't have been able to see it because every trace I broke was under the socket.

Jeff

A properly desoldered socket should fall off on its own. You should never pull on them as you just learned. If anything a slight twist back and forth with break any remaining solder and minimizes the chance of pulling traces.
 
Boy did I screw up. I desoldered the cpu socket and when I pull it out I pulled up about 8 of the traces on the top side of the board. Now I've got to go back and patch all of that. Ughh! All of the legs appeared to be free from solder, but evidently there was still some on the top side. I wouldn't have been able to see it because every trace I broke was under the socket.

Jeff

Next time, especially on those cheap-ass sockets midway used, pull the plastic off and remove the pins individually.
 
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A properly desoldered socket should fall off on its own. You should never pull on them as you just learned. If anything a slight twist back and forth with break any remaining solder and minimizes the chance of pulling traces.

every pin moved individually. I could move them from the underside. The top side looked desoldered. I didn't have to pull very hard to remove it, but I did have to pull. Oh well. Just a little more work.

Jeff
 
Next time, especially on those cheap-ass sockets midway used, pull the plastic off and remove the pins individually.

Agreed. I HATE those bally PCBs. The slightest heat lifts those traces right off the board. I do the same for TTL removal. Clip the IC off from the top and then remove the legs one at a time.
 
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