Some people will disagree with me on this.
But I used a company called GALCO to repair our power supply in our MV45.
They are located in Michigan and I belive they are a GE Fanuc certified repair company.
They were about half the price of Yaskawa to do the repair. ( $900 compared to $1800 )
I would definately see what the OEM would charge to do the repair first.
The OEM may be able to test it better and know of common problems before the repair.
They may even test it to see if it even is the problem.
In our case it was a little more painfull, our machine would intermitantly shut down.
Sometimes every 5 min other times 15 hours before it would shut off.
We replaced the obvious possible causes, door interlocks, swithces, moved relays, replaced relays, replaced cooling fans, inspected limit switches, ran new wires, rebuilt the power supply.
Nothing seemed to help.
Because the repair of the power supply was done by a private rather that Yaskawa, Yaskawa is still saying it may be the problem because they did not repair it.
Be prepared to get the run around if the power supply does not solve your problem, if it is not rebuilt be the OEM.
Now we are to the point where it may be a board, we sent this straight to Yaskawa for inspection then repair.
My advice for you is this, make absolutey sure that it is the power supply before you start heading that way.
Most service techs will quickly blame the power supply, and it is a real commmon problem.
But it could be so many other things, bad power, bad relay, broken wire, bad door interlock, bad off button, the list goes on forever.
You are already better off than we were because your machine is staying dead and not powering back up like ours was.
http://www.cnczone.com/forums/showthread.php?t=41086 (Mori Seiki MV45)