Surprise repair call - Neve 8078

Got a surprise repair call for tomorrow, a Neve 8078 apparently having power supply issues. Regular tech not available, this is not my usual beat but the boss wanted to help the guy out.

From the best I can find out, it's an 8078 console, from 1978, 62 channels. Has four Coutant power supplies, probably 4 rack spaces with a green/gray blank front panel. Most functions on the console suddenly not working, like mute lights work individually but not from automation such as solo in place.

The owner isn't technical enough for information much beyond that. Has a whole box of schematics but probably can't find relevant ones to send before tomorrow.

Advice welcomed.

This might not be relevant to the 8078  but I used to work with an 8068 at a TV company which suffered from strange problems with switches not working intermittently.
We eventually found that there were earth buses connected to screw terminals which had worked loose over the years. Tightening the screws fixed a whole load of seemingly unrelated faults.
The  terminals were located at the right hand end of the desk as you look from the operating position and I recall that they were low down by the bottom of desk. There was a bundle of green wires (one for each group of eight channels) going into large screw terminals.
Good luck! Dave.

I don't recall if he 8078 has a bipolar power supply or not, but I would be willing to guess one or more supplies is no longer outputting what it is supposed to.

Turned out to be a GFCI wall outlet tripped. It tripped again while I was there, so I swapped everything between the two outlets powering the beast.  Likely it's the GFCI going bad, so basically it's left in the next stage of searching out the problem.

Total of 5-6 power supplies, one with bipolar for an updated center section and then four +24vdc (and only +24vdc) for the original parts of the console, plus one more at the bottom I didn't look too closely at.

In a round about way I was correct. power supply no longer working. 

glad it's the outlet and not the supply.