
AC Repair and Adjustment Procedures
FRP 6: Daughter Card Replacement
HMM-168-A
Cray Research/Silicon Graphics Proprietary
47
Figure 20. Tightening the Retaining Screws
6.
Check for a voltage-to-ground short on the PEM after you install each
daughter card (a voltage-to-ground short can be caused by a bent pin on
the daughter-card connector):
a.
Measure the resistance between the PEM’s input power bus and
ground to ensure that no voltage-to-ground short exists. Refer to
NOTE:
In most cases, EV5 PEMs indicate less resistance than EV5.6
PEMs.
b.
If the resistance on any PEM is 10 ohms or less, remove the daughter
cards one at a time and check for bent pins. Retest after you remove
each daughter card. Repair any bent pins if possible. If either the
daughter card or motherboard is faulty, replace it immediately.
7.
Install the module (refer to
).
Step 5
Tighten this
screw first.
Tighten this
screw second.
Tighten this
screw last.
Tighten this
screw third.