Nortel Passport 15000, Hardware Installation And Maintenance, Page: 733 / 874

Chapter 17 Hardware procedures 733
Passport 15000, 20000 Hardware Installation, Maintenance, and Upgrade 5.2S2
Removing a temperature sensor for an upper cooling unit
Remove an upper (front) cooling unit temperature sensor to replace it or as
part of removing a shelf assembly.
Prerequisites
• You must be familiar with “Safety considerations and best practices”
(page 53).
• The upper sensors are located in the airflow space beneath the rear of the
breaker interface panel (BIP). The sensors are labeled S1, S2, and S3
from left to right looking at the rear of the BIP. See the figure “Location
of upper temperature sensors” (page 734).
• Minimize the impact or risk of having an out-of-service temperature
sensor by “Installing a temperature sensor for an upper cooling unit”
(page 542) immediately.
• You need a step ladder to see the top of the upper shelf assembly and a
medium non-magnetic one-piece Phillips screwdriver with a very short
shaft.
Procedure steps
1 At the rear top of the upper shelf, locate the upper temperature sensor to
be replaced.
2 Unplug the cable connector from the temperature sensor assembly. Apply
gentle, even, steady, and straight force. There are no tabs on the
connector to engage it. Refer to the figures:
• “A temperature sensor on the bracket assembly NTHR68AA for a
cooling unit NTHR52AA” (page 735)
• “A temperature sensor on the bracket assembly NTHR68AB for a
cooling unit NTHR52AB” (page 736)
3 Unfasten the sensor’s 2 Phillips retaining screws. If you drop a screw, you
must retrieve it to prevent equipment damage.
4 Put the screws aside for re-use.