Nortel Passport 15000, Hardware Installation And Maintenance, Page: 453 / 874

Chapter 17 Hardware procedures 453
Passport 15000, 20000 Hardware Installation, Maintenance, and Upgrade 5.2S2
— a flashlight to see inside the cooling unit while using one hand to put
electrical tape on the temperature sensor connector
• The location of the mounting screw is different for each version of the
lower and upper cooling units. Refer to these figures:
— “Location of the fan controllers inside a cooling unit NTHR51AA or
NTHR52AA” (page 456)
— “Location of the fan controllers inside a cooling unit NTHR51AB or
NTHR52AB” (page 457)
— “A fan controller for inside a cooling unit NTHR51AA or
NTHR52AA” (page 458)
— “A fan controller for inside a cooling unit NTHR51AB or
NTHR52AB” (page 459)
• When a fan controller is removed to increase access to removing a
temperature sensor, insert the same controller instead of a replacement.
This ensures that a working controller operates with the replaced part.
Procedure steps
1 For an NTHR10AA fan controller as shown in the figure “A fan controller
for inside a cooling unit NTHR51AA or NTHR52AA” (page 458), examine
the replacement fan controller to determine if it is already mounted onto a
carriage plate.
• If the controller is already mounted, continue.
• If the controller is not, remove the faulty controller from the carriage
plate by unfastening its 6 M3 screws. Mount the replacement
controller in its place using the same screws. Tighten the screws to
snug (no extra turn). Tightening beyond snug can crack the carriage
plate.
2 When installing an NTHR10AB into an upper (front) cooling unit
NTHR52AB, you must unplug the temperature sensor that is on the
module as shown in the figures “A fan controller for inside a cooling unit
NTHR51AB or NTHR52AB” (page 459) and “Cable connections inside an
upper cooling unit NTHR52AB” (page 461). This also applies to the fan
controller of the upper cooling unit that is used in the lower position of a
shelf-based (rack-mounted) Passport 15000 or 20000 in switch packages
NTQS04 or NTQH04.