NBA Jam Graphics ROMs Failed Test

Tkaz

New member
Joined
Jul 10, 2024
Messages
3
Reaction score
1
Hi all, I have a 1993 NBA Jam that is working, but has some jumbled graphics. Chips UJ22, UG23 & UJ23 all fail, is it as easy as replacing the chips or are these three connected and I need to look at the PCB for bad traces?
 

Attachments

  • IMG_9892.jpeg
    IMG_9892.jpeg
    231.4 KB · Views: 5
  • IMG_9886.jpeg
    IMG_9886.jpeg
    191.8 KB · Views: 4
if you have the capacity to replace (eprom burner) I would take them out, read and compare with romident to see if they are bad.
If chips pass romident, look at sockets and tone each leg front to back.
If still jacked up, look for legs on solder side touching, some are long enough to be bent down and touch where they shouldnt (shout out @mecha )

If STILL jacked up, then i would look for damaged traces.
 
Unfortunately I don't have a way to test with a burner, I've reseated a few times with no luck. Anyone close to Charlotte NC that could help out?
 
Ordered, I figure I'll have many uses for it over time, need to check a sound ROM on my Grand Lizard as well
 
Ordered, I figure I'll have many uses for it over time, need to check a sound ROM on my Grand Lizard as well
GQ4x4 isn't the best programmer, but for the money it's a great value. the games you intend on using it with should have 100% compatibility. when you get into the older, smaller roms like 2716 or 2732, you need a 9V transformer (external power) and depending on manufacturer things can get a little weird. 2764 I've found is the worst. lol

I had a Mortal Kombat II single board years ago where I believe the UG22 rom showed bad, and it wound up being a bad trace between UG20 and UG22 causing the error. you should have continuity between all the pins except the data lines, which run to the UE13 Williams Custom Chip. you can find the schematics on arcarc

I would venture if you have popped legs to UE13 that can cause rom errors too
 
Back
Top Bottom