Hi everybody! I'm facing another sys 6 cpu with another trouble
It was installed on a Time Warp, some acid around battery pack, completely blocked.
So I started with the usual first steps: remove all the damaged components, clean the tracks and stopped the oxide with water/vinegar solution. Once replaced the ICs it's time to perform the test: with both test roms (Leon and Andre Boot) the board is ok, also the rams and roms are ok, but... once in the pin, the game is freeze: no controlled lights on the playfield, all the display shown zeroes, and I cannot use the diagnostic button on the coindoor.
At the bench I noticed that with the multimeter setted to "check continuity" the pin 20-21-22 of IC19 has continuity when the battery are installed. Of course I've done all the test without battery, new 5101, check tracks... but the game still freezy as described above: no lights and display blocked with all zeroes.
Some suggestions about where to check and act?
Thanks as always!

IMG_20170330_234855 (resized).jpg

Thanks for your prompt reply!
I will check the IRQ signal. About the GND hole, I've faced some board with this trouble but the symphtoms are different, especially the LEDs behavior. Here, this board acts as if is completely good!. The LEDs remain lit after flashing without driver board, and gone off if putted in the game.
The selection chip is carried by IC15 (74LS139). With green roms, if there is any problem, I think the CPU remain locked. Right?

... the test is ok also with the 3 green roms installed so it means that nothing crash apparently... strange thing

Hi guys! Finally, in the poor time available, I've found the culprit...
It was the IC 25 (4020). Once replaced the pinball started to work properly again. Of course, also the killed 5101...
I want to thank Marco for its support and for his kindness in sharing with me his knowledge
Thanks!!!
Ciao