SE/30 Welcome to Macintosh

[Chopsticks]

I would take a good look at UL11 (ADB) and check all the pins are connected to the right place, there is a cap right next to it that can leak out and go underneath that chip, If possible remove and and then resolder it, also it connects to one of the3 VIA chips, so I'd check out the connections on UK12 as well, also checkout Q3 next to the ADB chip

 

[Cinan]

I reinstalled OS 7.5 and all seems good,  took the opportunity to wipe all the partitions an clean it up.  Looks like that has fixed the bus error issue.

 

[Cinan]

BTW,  the trace fix also fixed the lack of sound.