Finally I have Tekken in fighting shape!
Here are some pictures of the reassembly. Getting that heavy bottom plate to its place alone was the hardest part.
Getting there...
Almost done! I also used some glue so this will be the last time this cabinet will be taken apart... If I sell the house it will go with it
While it was in parts I cut the ground wires from JAMMA 27 to add P1 and P2 number 6 buttons for StreetFighter etc.
These should be the ones HAS Extension cable uses
And BEHOLD! Today was time to test it! And it works
Except those 6-buttons are still not working...

I made sure my HAS extension cable has dip-switches on p1 and p2 b6 turned to ON and I have CPS2 kick harness on my CPS2 multi which then goes to that HAS extension. Any ideas why those 6 buttons do nothing? I tried with StreetFighter and Darkstalkers. Buttons from 1-5work just fine.