NBA Jam TE crapping out

[Malenko]

game starts fine, passes all rom checks and diagnostic screens, the kids play for a few minutes then the game just has scrambled video but still plays blind and the sound effects play as normal. Ive tried the game in both my MKII cabinet and my Killer Instinct 2 cabinet. Despite the fact the game passes all ROM checks I pulled cleaned and reseated them, same thing happens.

Any ideas or do you guys need pix?

I find it hard to believe people are getting Galaga from 1981 to run by hitting it with a can of air and I cant get NBA Jam TE from 1993 to run right no matter what I do


this is the ONE game my nephews love and I made the mistake of Selling my NBA Jam boardset thinking this TE version would last a while

[Mauzy]

There's too much to go wrong with newer boards as opposed to the good old Galaga and Pac boards. That and the old boards have been around long enough that every problem under the sun has been documented.

Another example like that is my parents' 04 Yukon with every feature possible added to it. Something goes out on that thing at least once a month. My 99 Cherokee with has 144K miles on it and it runs damn near perfect. The only thing Ive done to it in over a year was put on an exhaust. All my Jeep is is a metal box with a straight 6 and a heater. None of the fancy crap that goes wrong on my parents' vehicle.

Good luck with your board. I had an MKII board that had sprite issues I never resolved. Just sold as partially working on ebay a few months ago...

[MonMotha]

Check your power supply voltages and perhaps replace the power supply if it is questionable.  Bad power can cause all manner of mysterious corruption issues.  If that fails, you may have a bad RAM or something like that.  Upon startup, there is a scratch RAM test, but I don't think it checks video RAM.  There may be an option in the test menu for that.  Of course, run any tests you find to see if it'll come up with anything.

Does power cycling the game fix things immediately, or do you have to let it "rest" before it'll work again?

[Malenko]

I only doubt the power supply because it happens on 2 different cabinets, also the game has ran fine for almost a year, this was sort of "out of the blue"  I havent had the time to test the voltages (but I will) but both cabs are factory wired Midway Cabs.

my luck its something small, simple, and EXPENSIVE

[channelmaniac]

Try putting slight pressure on the surface mount chips to see if pushing on one makes the video come back. If it does, that chip will need to be reflowed.

Also, get a can of component cooler or use a can of air turned upside down so the liquid comes out and spray the chips one by one to see if you have a component with a heat related failure. Once you figure out which one it is then post back here with details and part #s off the chip and someone should be able to help you.

RJ

[Malenko]

The plot thickens..................


just to be sure I ran every test they had in the operator menu everything came up green, including the scratch ram. Ive check the voltages, everything was fine, I cleaned and reseated all the chips, I even switched from NBA Jam TE V1.0 to NBA Jam TE 2.0 (I have all 4 rom version thanks to hobbyroms.com) and things have gotten just a LITTLE better.

I let the machine run for a while, then started a game (with Scorpion ) about 1/2 way through the second quarter the video dropped out but the sound kept going. the screen was basically all black with some random garbled stuff popping up for a few seconds. I grabbed my camera and started to take a pic when MAGICALLY the video came back! Ive had the machine running for a while now Im gonna check on it occassionally to see if the video scrambles again and if I can get an image of it.

Any ideas what could cause this?

[MonMotha]

Sounds like it could be a heating related issue as channelmaniac brought up.  As things warm up, a loose solder joint or internal chip interface will expand at a rate that is usually different from what it is supposed to be in contact with.  This can lead to an open connection.

I hesitate to rapid cool irreplacable chips using the canned air method, though, as such actions can easily break internal bonds or delaminate package interfaces from the rapid, uneven temperature change.  Pressing on the chips can be effective, though and is safe.  A visual inspection can also work, but you have to know what to look for.  The surface mount chips are the ones of interest, here.

If you find a chip with a loose interface, reflow all the pins.  If you found a possible problem visually, you might want to start with just that one pin.

[Malenko]

I think I found the problem, thanks to you guys!

when the video scrambles, I applied some pressures to UJ7 surface chip and the scrambled video  goes away and the regular video comes back. I'm going to reflow the solder tonight and hope I dont make it worse. I appreciate all the help guys!