Interestingly enough, it mentions checking the
temperatures of the RAM (ICs
Z27 through Z34) as part of the official RAM troubleshooting procedure - hot
RAM -> "REPLACE RAM", apparently. Replacements are to be "4116 type
Dynamic
The Radio Shack technical manual warns you that a RAM with supply line
shorts can get up to soldering-type temperatures, and that you should be
careful touching the RAMs to detect a bad one...
To reset the machine, apparently it's necessary to
hold down 'Break' and
'Reset' at the same time.
On a TRS-80 with a disk controller, this will cause it to ignore the disk
system and run the ROM BASIC. It's the way to start up a disk-based
machine (or any M1 with an expansion interface, which contains the disk
controller) without a system disk.
-tony