Broke all of a sudden!

Hello,
I have 6 preamps, 1 DI and 1 compressor in a rack, and everything has been working very well until yesterday, when I switched on the power. All of the power lights blinked once, then went off, and there is a pulse coming across several channels of the AVID Omni (which the SCA preamps feed to).
The fuse is good.
There has been no activity in that area of the rack for months.
Any thoughts?
I have 6 preamps, 1 DI and 1 compressor in a rack, and everything has been working very well until yesterday, when I switched on the power. All of the power lights blinked once, then went off, and there is a pulse coming across several channels of the AVID Omni (which the SCA preamps feed to).
The fuse is good.
There has been no activity in that area of the rack for months.
Any thoughts?