Pacman Just a Color Prom issue?

Zinfer

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Started working on Pacman yesterday. Replaced a couple bad Eproms with original proms. It fired up, and plays fine, but it looks really whacked. Is this just a color prom issue or do I have other problems here?
Can color proms affect the eyes of the ghosts running home? I recorded a demo to help describe the problem:
I think I'm right on with 4A and 7F needing replaced, but you tell me..

http://www.youtube.com/user/zinfer1?feature=mhum
 
Am I just seeing things or does it look like the ghosts return back to their home really fast after being eaten?
This could be a color prom issue but I think there is something else going on with the board. If you notice pacman is blue but changes color only when going up. I have seen this before on a mspac board. I might have it in my repair logs, I can check in a day or so.
At first thought I figured you had pac plus proms on there but the colors dont look right for that. If I had it on the bench the first thing I would do is swap in some known good proms and go from there. If you need the proms I have them in stock.
 
I had ordered some Eproms some time ago, however 5F and 6F were proven bad last night, so I threw the old proms back in. At least it runs now, but yea, those are supposed to be just the eyes running back home, instead it's the full image ghost, all of them in white.
The colors are all whacked, so I'm just presuming if I replaced 4A and 7F proms that maybe it'd fix it. The maze is also supposed to be blue, not white.
Notice that you can't see your score either. Color is too dark.
When eating a power pill, the ghosts turn transparent with green dots and squiggly mouths but no blue.
I'm hoping it's just the color proms. I'll try replacing those first. I contacted hobbyroms and he says he can send me the 5F, 6F and the Color Proms for $20 shipped. I'm probably going to need to order some sockets though too.
Wierd looking ain't it?
 
Although I dont think its a monitor issue....have you proven the monitor to be good?
Replace those proms and let us know what the outcome is.
 
I just got a mail from Steph and he said that it would probably be more time proficient if I ordered the color 4A and 7F Proms from you Riptor, being he's in Canada. As far as I know the other Eproms tested out good, but 6F and 5F need replaced. I could just put the 2532's in stock and go with a whole new set.
As I said earlier I've thrown the old original proms in there for now and the results are what you've seen.
I'm going to try one more thing. I'll put the good Eproms 5E,6E,6H and 6J in place of the Proms and see what happens with that. So, if you can send me some color proms (4A and 7F) that'd be a good start. I'll know more tonight after I try replacing those Proms with the Eproms. I really don't expect a change.
 
Yea, no change. So I'm thinking the problem could be in 5F, 6F, or 4A and 7F Color Proms. If it's not there, then I'm stumped. I haven't capped the monitor yet, but it's another G07-CBO and I will be recapping it. I should have ordered 2 G07-CBO cap kits, I have another in a Dragon's Lair I was going to recap first.
 
Alot of programmers wont do proms. If you get the proms from me they will be programmed, labeled and ready to go. Pm me and let me know what parts your looking for and I will give you a price.


Thanks,
Mike
 
Am I just seeing things or does it look like the ghosts return back to their home really fast after being eaten?
They looked normal to me, just the wrong color. I believe when it does the eyes, it turns the ghost color invisible, so all you see is eyes when they go back (in the graphics, there's no separate sprite for just eyes). On a few of the bootlegs, you also see white ghosts going back to the pen. (here's one on Galaxian hardware, from MAME)
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Okay, well I ran the cap kit on the G07 and that did help considerably as far as fuzziness as well as brightness and I actually got my red back again which now displays a score.
I then recieved the 4A and 7F color Proms. I replaced the old proms that were in there and to my surprise it did not affect it in the slightest. So, I guess I have to wait a couple days for my Eprom eraser to arrive so I can clear out these old Eproms and attempt to burn an entire set.
I was for sure the problem was in the color proms. Damn!
If my Eproms turn out to be bad I'll need to order an entire set Riptor.
 
Started working on Pacman yesterday. Replaced a couple bad Eproms with original proms. It fired up, and plays fine, but it looks really whacked. Is this just a color prom issue or do I have other problems here?
Can color proms affect the eyes of the ghosts running home? I recorded a demo to help describe the problem:
I think I'm right on with 4A and 7F needing replaced, but you tell me..

http://www.youtube.com/user/zinfer1?feature=mhum

Hi Zinfer

Is it an original Midway board?

:)
 
Well I never have been able to replace Proms 5F or 6F. That's why I thought that at least burning those may yield some results as the checksums, if memory serves, were not what they should have been.
The board is marked PacMan by Midway Manufacturing.
 

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Back on the 19th of this month I posted in this thread about 5F and 6F. But with running between working on 4 different cabinets it all starts getting fuzzy anymore. I'll probably have to recheck the original Proms again.
I'm thinking that Eprom eraser will arrive probably tomorrow. So I'll get into the the thick of it again then. I have 1 bad set of Pacman Eproms with 5F and 6F checksums wrong. I'll need to go back and retest the original Proms, which I have in there now.
If it's not 5E, 5F,6E,6F,6H,6J,4A or 7F then I'm on the verge of being stumped. 1m - 3m??
I'm going to give it one go of having a complete working replacement Eprom set of 5E, 5F,6E,6F,6H and 6J before I'm ready to say it's not the Eproms/Proms.
I can't see a Ram error doing this, but stranger things have happened.
 
Color issues like that are more likely in logic or ram. 2125 ram and supporting chips is where I would be looking.
FYI, if I remember right I had issues trying to read some of those factory proms. Known good proms wouldnt verify. I dont remember the exact details its been a long time, I usually chuck those old rotton proms in the trash.
 
All my Pacman boards I have fixed by swapping parts between boards

If you have access to a known working board you can swap the ICs mentioned one at a time.

I have fixed many doing this :)
 
yea I'm the same way, but I need to get a good working set of Eproms going in there first before I decide to chuck any Proms. :D
Those old rotten Proms are the only thing keeping this thing alive atm. Unfortunately I don't think the Ram is socketed, so I'd have to actually KNOW which one is acting up. I do have a logic probe and an oscilloscope and a guitar. One day I hope to learn how to use them.
As far as having two Pacman boards, nope just the one that came with the cabinet presently. But yes I've fixed a few boards myself. Having known good components to swap with makes a world of difference. I think the most difficult was the 'Sounds Good' board used in Rampage and Xenophobe. Only way I fixed it was by having a second GOOD pcb. I was lucky with that in that the IC was socketed. I shudder to think of swapping parts by unsoldering them without knowing what readings I should be getting from such things as a logic probe. In this case I think you'd find the problem with a FLUKE 9010A if you knew how to use one.
Either that or taking voltage readings with a multimeter on each RAM component. But then that's how I've found bad RAM in Williams games. I dunno if Midway Pacman RAM would be anywhere similar.
But this is a bit academic at this point until I get that Eprom eraser in hopefully by tomorrow, definitely this week. I want to see how it acts with a good checksum set of standard Eproms.
Unless I get a better idea on ram testing or such, I'm going to do the Eprom rewriting and after that, pack the board up and send it off. I'd love to fix it, but not going to fritter away dollars needlessly.
 
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Your not going to have much luck testing the 2125 rams with a logic probe. No, they are not socketed unless someone else installed sockets there. Sometimes you can find a bad ram by piggybacking them one at a time. There are certain symptoms associated with certain rams but I cant help you narrow it down with your problem. Worst case you can replace all 4 rams and rule them out. You should socket them if you replace. I sell D2125 pulls for dirt cheap on my site if you need some.
http://store.pacmandotcom.com/ram/45-2125-ram.html
 
Well if there's only 4 of them then it's worth a shot to try replacing them. Your talking about 2K, 2L & 3F, 3H?
 
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