ULEIS

Last Friday (9/25) the ULEIS TOF-1 HV was turned off as part of a test to
investigate interference between the two time-of-flight analyzer boards.
This test requires a solar particle event to be in progress in order to
acquire sufficient statistics to characterize the instrument performance.
With the larger particle event that started on September 30, this test
is being continued, and excellent counting statistics should result.

It is anticipated that the TOF-1 HV will be turned back on sometime next week.

This test complements an earlier one carried out in April 1998, when 
ULEIS was operated with the TOF-2 HV off in order to investigate the same
problem.  Analysis of the test results will take at least several weeks
after the conclusion of the test.


S3DPU

On Monday, September 28 (DOY 98-271) the S3DPU experienced its fifth full
reset, putting SWICS and SWIMS in their Standby (no HV) Mode and causing
SEPICA to be turned off completely.  This is the same sequence of events
that has transpired for all 5 resets.  In the days preceding this reset
there were at least 7 "minor" resets, where various counters in the DPU are
set to zero.  Such minor resets have also been seen prior to earlier DPU
resets, but not in such quantity.  On Wednesday, during the reconfiguration
of the three sensors, the DPU at one point stopped accepting commands.
This condition was resolved by running a procedure that had been used in
the past to fix the same problem.

On September 2 the S3DPU had been power cycled with hopes of increasing its
stability, and in the meantime no patches were uploaded and no memory
dumping was performed.  Efforts are underway to trend the DPU HK data items
from early in the mission to search for signs of change that might help
explain the resets.  The activity level of the DPU is also being examined
to see if there is any correlation between resets and increased solar
activity.  Meanwhile, the DPU engineer at the Technical University of
Braunschweig, Germany, is sending diagnostic equipment to the University of
New Hampshire to be used with the engineering model DPU that has been under
test there, and which has also undergone resets.