We inherited a 5973N (turbopump), and it had been working well as of a year ago. After an extended period of vented shutdown, I powered it back up, and found that the MSD will not initialize past "loading OS" on the local control panel. The power light in the back is on, but the heart light also stays on constant (no "heartbeat" or SOS light pattern). The turbopump and rough pump are pulling vacuum well (2 x 10^-5 on an external gauge). Chemstation can find the GC but not the MS.
I have tried (but have not resolved the problem):
1) power cycling the MS, power cycling the computer, and power cycling the GC to see if the error would clear.
2) unplugging the LAN connector to see the MS could not load the OS due to a communication problem.
3) Holding the menu button down on the local control panel to see if I could enter controller mode or reboot the MS.
I assume have some problem with the memory on the MS. Any suggestions of what this could be, and what I could do to diagnose the problem?