MEK6800D2 restoration

I'm in the process of restoring a Motorola MEK-6800-D2 evaluation kit. The kit was adapted and has its RAM on a separate board through an EXORciser backplane. After putting everything together and verifying that all looks good, I've applied +5V from an ATX power supply. The '-' prompt appeared, the JBUG monitor program is working and I even dumped the ROM and some EPROMs over the cassette port and decoded them on a PC :) So far so good, but to do anything cool I need the RAM board going. The problem is that this (custom wire-wrapped board) is using 16 MCM4116 chips. They need also -5V and +12V. Ok, these are available on the ATX power supply but I'm affraid of doing anything stupid that might blow up something. What would you check before applying these additional power levels ? I've been verifying a bit with an ohm meter that the -5V and +12V leads are not by accident connected to anything they shouldn't but not sure if that's a good way. I also read in the datasheet that you need to apply -5V before the others and removing it after the others. How would you do that ? I was thinking on having the -5V and GND permanently connected. So after switching on the power supply it will have -5V right away. Then manually connect a additional cable having GND, +5V and +12V. On power off do the reverse. Is that a good idea ? Not very handy but if it works I'll live with it. Thanks for any advice, Wim. -- hackbox dot be slash museum