Hi MO Man,
I assume you have an M-32B or possibly a M Plus control? (the M-32A has a floppy drive on the front of the CNC card cage) And your location you list has had some bad storms around the time it was off??? Or maybe a one time battery alarm when turning on after the couple of week idle time??
I again assume from your posts that the obvious has been done, and the troubleshooting gets more complex.
I have worked on several VTC-20's, Very similar just a larger machine. None I have have worked on had an air to air heat exchanger, just fans that draw shop air thru the electrical enclosure. If this is the case, look carefully at the large board below the CNC chassis full of relays, for burns. Even shine a strong light behind the board and look for dark areas apparing as irregular dark shadows versus the defined lines of the circuit traces. I have replaced several of these boards that had burns causing strange problems. When 120 VAC gets crossed up with the 24VDC circuits takes out the input/output board in the CNC. All the sensors and solenoid control goes thru this board.
If there have been bad storms, even with power off, memory can become corrupted causing strange problems. A weak battery also causes this. For the M-32B and M Plus, home the machine, backup all programs tool offsets and then another backup with a small program and anything else you can check on the save screen, tool offsets, tool library, parameters etc. If using a microdisk make 2 copies and compare each one to memory. Obtain the initalize control proceedure and also the proceedure to save parameters to flash and save to flash. Mitsubishi is at 1-847-478-2500 and select tech support. You need the machine S/N and it is a free service from them. When cycling power for the initalize there is a small toggle switch on the CNC power supply you can use, lift to turn on and down to turn off.
Make sure you use correct proceedure for the M-32B (MC-161 card) as the MC-111 card for the M-32A does not have flash. Re-load from flash, clear program file, etc.
There will be some fiddling getting the control to know what pocket the tool magazine is on and try only an air tool change at first (no tools in magazine).
The M-32A (MC111 Cpu) does not have the program that runs the control in proms, it must be loaded from floppies using the drive on the card cage. I think there are 2 disks to do this, they are a non standard format and may be lost by now, or unreadable due to age. Proceed with caution, because the control will be brain dead after the switches are flipped and power turned on. The only way to bring it back is with those disks!!! There are machines at used machine dealers that are brain dead because of this, they don't sell for obvious reasons. Replacing those disks is $$$ and down time. Again be careful.
I am referring you to Mitsubishi not Mazak for the initalize proceedure. They made the control and many Mazak tec's refer this to Mit. if it needs to be done. The tec's there can guide you on the phone better than we can guide you on this site, if you need it. And their tech support is free!
I hope the detail isn't overwhelming,
Bill