Hi - I’m tackling a very similar, battery bombed SE/30 and have managed to get it to boot to the “Welcome to Macintosh…” splash screen after many hours repairing tracks and vias, not to mention cleaning up corrosion damage. The worst thing is that the corrosion renders the solder “unmeltable” if that’s a word. It turns into a grey powder which can only be removed by physically picking it away with a very sharp scalpel point or pin.
From my experience, the broken PCB tracks you can see are a bit like the tip of an iceberg because there will be 10x as much damage below the surface so to speak. I ended up using a multimeter to buzz out all the address bus and data bus lines between the ROM SIMM and the CPU as well as between ROM SIMM and the F258 chips. I found lots of breaks which I repaired with either fine tinned copper wire to repair tracks or enamaled wire-wrap wire to repair the vias by jumping between the ROM SIMM pins and CPU or expansion slot depending on where the break was.
This is my first classic Mac refurb but I am an experienced electronics hobbyist and have a degree in electronics. However, I really was close to giving up by the time I heard the boot chime and got the floppy drive with question mark. I then attached a configured SCSI2SD device to get to the first stage of booting.
Unfortunately the boot process doesn’t get very far but I’m hoping that’s due to the fact my RTC/PRAM chip doesn’t yet have power restored as I’m waiting on some diodes arriving to replace D1 and D2 which were dissolved by lithium hydroxide or whatever is produced by an exploding batttery. I’ll see if I can upload some photos to show just how bad my board was when I got it. I had to replace Y2 and had to remove the RTC chip to clean out the corroded solder from the through holes before tinning the holes and refitting the chip. I also had to reflow the solder on the ROM SIMM holder which was challenging to say the least. Ideally I would have removed it but that’s far from easy.
Anyway, my message is mainly to encourage you but also to make it clear this will probably be a bit of a challenge to get working. I’m not there yet either and for all I know I might never get my SE/30 fully working but it was a fantastic feeling to hear that boot chime late on Sunday evening! Fist pumps all round at that moment!
Good luck to both of us!