Ideas? Yes.....get a multimeter and start measuring voltages. You cannot "guess" a problem like this and simply shotgunning parts is not a fast, easy or sensible way to find the fault.
These are very simple, regulated supplies so a measurement of all the voltages should reveal exactly what area your fault is in which will narrow it down to a few components.
OH yes I forgot to say I tested the voltages
All is good bar the 68v, is only reading 22v.
