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Looking for help w/ a (Ms.) Pacman board...
gonzojoey:
Hey guys. I'm looking for a little help with Ms Pacman I recently acquired. When I got it, the video output was nothing but a screen full of P's that would wave from left to right. I checked out several troubleshooting guides and didn't see anything about "P"s, but since its similar to some other symptoms I found, I figured it must be the RAM, so I picked up a set of the 4K-R IC's from Bob Roberts (2114's). Now all i get is a flashing 0 near the top of the screen...
When i look through the troubleshooting guides, it says a flashing 0 usually means something wrong w/ 4-M, which I just replaced :banghead:
I do have another working board available to me, so I did try to swap the Z80 and VRam addresser boards to see if that makes any difference, but it didn't...so I don't really know where to go from here. Visual inspection of the board around the 4-M chip is fine, no cracks or obvious damage to the runs. I haven't tried to enter into test mode (honestly i didn't realize this board had a "test" option) but i can try that tomorrow to see if it identifies any bad RAM / ROM.
Is there something obvious I'm missing? Has anyone see this sort of issue before?
Any help you can provide would be appreciated.
Thanks Guys!
paigeoliver:
I don't have a lot of general tips to give you, however I do have a Ms. Pac hardware diagnostic daughterboard and a working boardset ready to send out and would be happy to do a board exchange or repair for $70 including shipping on my side.
gonzojoey:
Update...
I tried with the Z80 on the main board (eliminating the ribbon cable and daughter board), but it still comes up w/ a flash zero at the top of the screen...
I guess I can try swapping the 6E-6J Proms to see if perhaps one of those is causing the issue...
If i cant get this thing working, I might take you up on that offer paigeoliver.
mgb:
I'd say, try swapping the proms if you have them.
Are also cleaning the legs on the chips before you pop 'em in.
Those things get real grimey and that could cause bad contact.
Also a bad socket can be the case.
orion:
Bad socket at 4M?