Super Pang PCB problems

[arakissun]

Hello to everyone,now I need your help.
I have problems with SuperPang PCB.The game work normaly but today after 30min. gameplay it freeze suddenly and after turn off/turn on the power of the cabinet the screen shows this:

http://img194.imageshack.us/i/picture004vk.jpg/

This is the PCB:
http://img130.imageshack.us/i/picture005gm.jpg/

The one EPROM that is in the socket,after checking with programer it says that the ROM cannot be found(I use RomIdent).I dont know wich rom is this,or may be because the PCB is bootleg this rom is not in the MAME database.
http://img804.imageshack.us/i/picture009c.jpg/

This is some repairs that I see and dont know are they can be a problem,before this the PCB works
http://img16.imageshack.us/i/picture011do.jpg/
http://img39.imageshack.us/i/picture012fl.jpg/
As you can see this is chip on chip soldering

One more thing,the sound of the PCB.It was strange.The harpoon shoot and the pang of tbe ballons was normal like sound,but the background musik was a little bit fast than a normal.I think this is connected with the sound chip,but I dont know is this chip can cause the problem.Here is some reapirs too:
http://img130.imageshack.us/i/picture010cx.jpg/



For final I can say that I have one more PCB(Thunder Dragon),that was gave me without pay,with the same problem with the picture.So I think the to problems are similiar,and If I can find the fix for the SuperPang will find th fix the other PCB


So,I need to know from where to begain to check for eventual problems.Every sugesstions will be helpfuly