Laser 128 problem

["Col.Brewster" <Macvsog@cris.com>]

I have a Laser 128 and it seems that the power supply might be getting
weak or starting to fail. What is happening is that the computer loses
part of its power after its been on for a while. Usually, if I access the
internal disk drive the screen goes blank and the internal disk drive
keeps spinning but it dosen't seem to be reading or writing. This happened
a few times when I didn't access the internal disk drive, so this is why I
think its the power supply. 
Should I replace it or try to repair it?

Thanks