> When I check voltages of PSU, -12 v is slightly out of range of spec
> (manual says, all voltages should be in +(-)5% tolerant.
> Can this be a problem?

Hard to say without intimate knowledge of everything on the board, but
I'd guess that the -12V is probably only for the RS-232?  (Anyone know?)
If so, it is probably okay, since RS-232 is supposed to work anywhere
in the 5-15 Volt range.

You could try different baud rates, etc.  I think the default
is 9600?

You could try plugging in a video board.  Maybe the rs-232
chip died?  Do you know if the previous owner was using SRM or ARC?
Will ARC even talk to an RS-232 console?

> said all of them has broken rom

You could try the fail-safe loader.  The 164lx has a jumper that you
add or remove, no idea on the up1100.

> even mmj cable

What is an mmj cable?