I don't want to hijack the thread but I repaired a battery bombed SE/30 a little while back and everything works except I can't boot into system 6.0.8 without getting an error relating to "Responder" which I believe is an Appletalk extension. I also can't boot into 7.5.5 as it hangs during the bootup progress bar at around 15%. I also get errors related to the modem and printer ports if I use the "Snooper" diagnostic tool.I strongly recommend that, once you have a bootable machine, you check whether or not your serial ports work. Both the serial transceivers in my machine looked completely fine but had in fact been tanked by capacitor juice. Again, replacements are cheap and readily available.
So, this all points to a serial issue. However, I have tried replacing the 8530 SCC chip, the two SN75175 differential receivers and one of the 26LS30 differential drivers. I also replaced the RP2 and RP3 resistor packs which were shorted on some lines. The remaining 26LS30 seems to be working so I didn't bother replacing that last chip but maybe it's worth a shot? Was it the 26LS30s that you replaced or something else? Did you see any weird symptoms like mine?
Thanks.