Went to storage to paw through some more 110 and Portable Plus
bits and came up with another tidbit from the manual for the 82984A
128K Memory Card (p/n 82984-90004).
Turn the Portable Plus off with PAM f8. Press and hold Extend char
and Shift, then press and hold f8 for at least five seconds. When you
let go it will start up with a diagnostic menu. Note that the
Software/Memory Drawer test on Shift-f2 takes five minutes per 128KB
RAM, but it will tell you what sockets it thinks have ROMs in.
-Frank McConnell