Jr Pac-Man graphical glitch

CrazyKongFan

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I've got a bootleg Jr Pac-Man board that I'm borrowing from a friend, and it's got a slight graphical glitch. It's fully playable, but all the moving sprites (junior, ghosts, prize) look like a Picasso painting (all scrambled). I'm attaching a couple pics. The board itself looks like it's laid out like a regular Midway Jr Pac board, so I assume the parts are the same (I don't have a real one to compare it to, but it looks almost the same as the one on the KLOV page. It's also missing the DC conversion area, since it runs on straight DC). I assume it's one of the TTL's on the board, but I don't know enough about them to know which one. Last photo shows bottom, static junior and prize in corner look normal, but you can see the players junior in the maze just above it is scrambledThanks!

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I have never seen a bootleg jr board but the midway board uses a couple 7489 rams that always have leg rot. There are actually 4 on the board, 2 are sound and the other two are the ones you want to look at. The are on the end opposite of the edge connector on the midway board. Post a picture of the board if you can.
 
Here's a pic of it. It's probably not detailed enough to read the chips (the original file is though ;) ) Which positions are the 7489's located on a real Jr Pac board? I can only seem to find 3 on this one, although some of the chips are faded enough they're hard to read. I've found them at 2H, 7R and 7S. None are socketed and the legs look solid (they do have some black corrosion on the outside, but they're soldered to the board, underside looks ok too)

bootleg:
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for a comparison, here's a real Jr Pac board, from the KLOV page:
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Looks like they copied that board to the T. The 7489's are at 2J, 2H, 7R, 7S. Those bottom two eproms are probably the character roms and I believe the 2J and 2H rams are the moving sprite rams.
 
Yeah, I'd compared it to a pic of a real one and it looked almost identical. It's missing column 12, and has some of the stuff moved over a bit (and missing the DC conversion section), but everything else is almost identical (a cap here or there might be different or missing). Anyway, there's a different chip at 2J, labeled 825300 M53289P. I see googling M53289P, it's a 7489 equivalent. Unfortunately my local electronics shop is closed today thru Jan 3rd :( I've got a couple of those Pac-1/Pac-2 boards with some 7489's, but they're soldered on those too. Do any other common boards use them?
 
Lots of boards used them but they usually are soldered on. The midway Jrpacs were all socketed. Got an eprom burner? I would verify those roms first.
 
Doesn't it do a self test on all the ROM's on bootup? I do have one, I can try and verify them. I'll check with my friend who I'm borrowing the board from too...he might have some dead Pac boards in his stash to borrow the RAM off of.
 
It probably only checks the program roms. The game will actually run without the character roms on the board. The 7489 are soldered on pac boards, needs to be a jr pac.
 
OK, thanks. I'll try dumping the graphic ROM's first and see if they verify ok before I go hunting for RAM.
 
Just an update, no changes, but I just got a real Jr Pac board, and used a few parts to test. I swapped the eproms at 2E and 2C (6 and 7 on the bootleg board), assuming those are the graphic eproms, with no change. 6 and 7 looked good on the real board, and 2C and 2E looked the same (scrambled) on the bootleg board. I also popped out one of the 7489 RAM's on the real board and piggybacked it over one, then the other, in the graphic section on the bootleg board, with no noticeable changes. I didn't want to mess with them too much, because they have the above described leg rot, one of the legs on the one I removed felt pretty flimsy and I was afraid it'd break off with much more handling, so it's back in the socket on the real board. Guess I'll let my friend worry about it, since it's his board, now that I have a real working one...just was hoping it was a simple fix ;)
 
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