[Info-vax] Clock running very slow on an Alpha

[Peter Weaver]

I have a customer with a four node cluster of Alphas running V7.2-1.
Three of the Alphas are identical "AlphaServer 4100 5/533" machines.
All four machines have been running Multinet  V4.2 XNTP for years. The
XNTP configuration is identical on all four nodes, the SHOW LOG *TIME*
command on all four nodes yields identical results. I downloaded and
ran the TBO utility on the cluster, all three of the 4100's report;

$ tbo/info
%TBO-I-IDENT, OpenVMS Time Booster Rev 2.0
%TBO-I-INFO,  Systemtime: 25-AUG-2010 13:00:48.89
       Timeadjust: 0
       Ticklength: 8333

ANA/SYS returns the same values for these three locations on all three
4100's;
EXE$GL_TIMEADJUST:  00000000.00000000   "........"
EXE$GL_TICKLENGTH:  00000000.0000208D   ". ......"
EXE$GL_SYSTICK:  00000000.0000208D   ". ......"


One of the three 4100 machines servers recently started losing 15
minutes per day. I have restarted XNTP on this node several times,
each time the XNTPD.LOG reports that it acquired the peers (usually I
have only one peer but during my troubleshooting I added in the other
3 Alphas as peers) but nothing else. The drift file on this node shows
"0.000 0" I trield adjusting the time with TBO/DIRECTION=FORWARD/
RANGE=7200/DELTA=4500 (move the clock ahead 75 minutes over the next 2
hours) but even with that command the time on this Alpha was stil
drifting away from the other Alphas just not as quickly.

If I stop XNTP and run the ntpdate command then the clock jumps to the
correct time.

Can anyone think of anything from a VMS perspective that I missed that
could be causing this? If it boils down to hardware then what part
should I tell the hardware people I need replacing?