[Info-vax] Alphaserver ES47: Suspected broken CPU, unable to stop/cpu 2

[Robin Schrievers]

One of our Alphaserver ES47's is showing spontaneous crashes since a few days. As soon as we start queues and make the box work, it will crash within the hour with a machinecheck.

Every time that happens it seems CPU 2 is the issue:
~ERL-E-(logupdate) Logging PAL EV7Logout from cab: 00 drw: 01 instance: 00
 
**** OpenVMS (TM) Alpha Operating System V7.3-2   - BUGCHECK ****
 
** Bugcheck code = 00000215: MACHINECHK, Machine check while in kernel mode
** Crash CPU: 02    Primary CPU: 00    Active CPUs: 0000000F

I tried stopping that cpu with:
 
stop/cpu 2

but it won't let me. stopping 1 and 3 works.
I also tried it using the MBM console with this command:

SET CPU_ENABLED FFFFFEFF

as stated here: https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c03645983

any other way i can force that CPU to not be used to see if we are stable then?

Any suggestions would be greatly appreciated