To prove it's the CPU socket, Turn the amiga on without pressing the CPU. At the point where the GURU comes up, press the CAPS lock key at a constant pace. It should go on, then off, then on then off then on. If the CPU socket is dodgey, you will loose control of the CAPS lock key light. Obviously, if the LED on that key stays on or off, the CPU has stopped responding. If the Miggy boots fine with pressure on the CPU itself, then yes, there is every chance your socket needs re-working.
Please be absolutely 100% sure the Mobo & CSMKII connectors are pressed firmly together & if this persists for you, then you really need to Email this guy at the bottom of this page:
Anthony HoffmanI had these same symptoms on a CSMKIII & A.H. repaired it & for a very reasonable price too! Good luck m8! :-)