a while ago i bought a 5 IIsi's lot on ebay, One of them had no video, no bong...

So after closer examination, there was no ROMS soldered on the mainboard.

I ended up looking inside the other machines and its ROM simm was inserted into another machine, with roms already onboard.

so poped that out, and poped it in the one with no roms, and it booted up.

The IIsi rom simm definitely looks different then the SE/30 rom simm.

I think the SE/30 has a rom simm slot, purely because they could not find another square inch of space to solder roms on the PCB

the SE/30 is a cramed PCB.