Ok I'm kind of stuck with getting my BSD back to working and hoping for the pinside hivemind to come up with some ideas.
First of I'm still learning the ropes of repairing games. So i might need some further help as I can not 100% read and understand the schematics.

Ok what has happened and what has been done so far in a short summary:

- Working BSD was in Attract mode. Suddenly a ballsearch went off with solenoids firing and it smelt burned.
-> Machine turned off.
- When turning back on again, ballsearch goes on and the game is showing error on the optos #53 Top right Lane and #73 L Ramp entry
- Found a burnt C10 condensator on my 24 Switch opto assembly.
-> Replaced C10 and C7 with new condensators
-> Problem remains
- Noticed acid damage on the CPU from a former Battery damage (Has been this way when bought, had no clue what to look for back then, BSD worked for a year with it up to the problem)
-> Replaced almost all of the components of the CPU from the height of U12 downwards including IC's Resistors, diodes etc.
- Furthermore I noticed the missing LED light on 24 switch opto assembly, found a blown F116 fuse
-> Replaced fuse, Problem remains.
- Tested the switch Matrix on the CPU with a jumper cable from J207 to J209.
-> All switches showing off correctly
- Run a switch test on the game with everything plugged in
-> All switches register normally. I can even open and close switch #53 T R lane and #73 L Ramp entry. So I got no clue why I still get them as an error message.

This is about it. Any ideas or help for a fellow beginner

Thanks. Was my first solder job on boards but I'm pretty sure it turned out good.
I made an external battery holder that is placed on the side of the backboard.

Damn I'm sure I checked the leads on one side. But not sure if on both (edit: I checked pictures. Should be ok damage was not that big, pic attached)

The LED is lit on the 24 switch opto board after changing F116.

IMG_20200727_131524 (resized).jpg

IMG_20200727_131532 (resized).jpg

No Problem. Appreciate your help. Have a good sleep.

Yes this is the 24 switch opto board acrding to the manual and that was what I was referring to.

There i changed both capacitors and got the LED back on. But still got the ballsearch and switcherrors.

Ok will change this one too. Has the same specs as the others.
Will also check C 2 on the PDB

I will report back some time later when I did a reset.

Ok did a factory reset game starts up normal now.

Wow. If it was really that...