CPS 275 has a fuse, a voltage select switch, and from what I can see, a removable power mains cord. Check the fuse, check the setting of the voltage switch, try replacing the power cord (it's the same type as a computer power cord). The plug on the power cord may have been damaged when it was pulled out, if somebody tripped over the wire, or if the wire was pulled hard.
If that fails, the 275 manual is here:http://www.soundcraft.com
take the spaces out of the above link before copy paste to browser.
A tech who works in a music shop or electronics shop should be able to get it working.