Q*Bert background jumbled

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Ok so now that my Q*Bert is back together again I need to try and do a few repairs to the board. The first thing I did was make sure the +5 was okay and it's 5.02 measured across a TTL chip on the board. Looks like I'm having a problem with the main board. I guess the first thing I'll ask is should jumper jp12 be jumped or not? I ask because with it jumped the text is legible and the game looks more normal so it would seem that's the case, but I read jp12 isn't supposed to be. Here's a few pics of the background graphics issue....first with jp12 not jumped and then with it jumped. I have brand new mostek ram chips are new, sockets were metered and had continuity and each leg, and finally I verified the background roms were good compared to the MAME set. I'm not sure if the sockets could still be an issue even with continuity checks passing. Any thoughts on this issue? If it comes down to checking the 7400 TTL chips I have a logic probe, but would really appreciate advice on what to look for. Thanks everyone. I know Q*Bert questions get asked often.

Here's 2 screens with JP12 jumped. I will note the 0's on the far right cubes change to 1's as you jump on them....maybe a clue?

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Now the same basic screens without JP12...you can see it looks much worse, but from what I read, I thought it wasn't supposed to be jumped.

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Edit: Doing some general troubleshooting, I noticed H5 and H6 (SN74S161N) are running considerably warmer than other 74 series chips. I mean we all know something running really warm isn't good so maybe those are related to the problem(s) I'm having. From what I'm reading it looks like those are related to foreground.
 
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For fun I did some testing with my eprom burner on the current set of eproms installed and another set I've had for a while. Long story short is I verified and have a solid set of roms in with no joy. I think I'll take a look at the other sockets especially now that I'm looking at more than just background issues.
 
Any acid damage on that board?
Some yeah. Wouldn't you know the thing still had the battery attached when it was given to me...an old buddy of mine gave it to me and had sprayed wd40 on it for some reason. I can only assume it was an attempt to stop corrosion. It's not severe at least but I have wondered what factor could be playing. I haven't seen anything that jumped out at me as an obvious problem.
 
Pull rom 0-3 and check for corrosion in the sockets. Depending on how bad it is the corrosion usually runs all the way down rows 16 & 17. Post a close up pic of the top left corner of the board so we can see how bad it is.
Yes, most qbert boards I run across still have the original batterys.
 
Thanks again for the reply, Riptor. I'll take a look at those rom 0-3 sockets later on today. Here's a a few pics from the left side of the board. You can see it's definitely had some acid corrosion. Hopefully this thing isn't so bad I'm better off just replacing it.

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Thats not too bad, I have seen much worse still working perfectly. Also, correction on what I said. I should have said roms 0-2...three roms starting with #0.
It wouldnt hurt to go ahead and verify all the roms on the board. If you have several that wont verify you might have a different rom revision than whats in mame. I have run across this a few times. I might have both versions on my computer but cant remember for sure.
 
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Thats not too bad, I have seen much worse still working perfectly. Also, correction on what I said. I should have said roms 0-2...three roms starting with #0.
It wouldnt hurt to go ahead and verify all the roms on the board. If you have several that wont verify you might have a different rom revision than whats in mame. I have run across this a few times. I might have both versions on my computer but cant remember for sure.
Thanks again for the reply, Riptor. I didn't have much time to mess with it yesterday but hopefully I can get some more done this week. I did take a minute to do the test listed in that Gottlieb "On Target" newsletter where you remove JP21 to get rid of the foreground and put it on JP22 to get rid of the background. When I did that all my problems were definitely on the background section; foreground looks good. I'm wondering what kind of clue jp12 might provide. As you mentioned, it's not supposed to be jumped, but when it is, the background section improves significantly, especially the text.
 
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