Service Manual

GSM-205-523
Digital module replacement (MCUF, NIU, FMUX, BPSM, Alarm)
31st Oct 01
Maintenance Information: Horizon macro indoor
68P02902W09-B
CONTROLLED INTRODUCTION
Maint. 2–33
Replacing
digital modules
Removing a faulty digital module
To remove a digital module:
WARNING
There is a possibility of laser radiation when fibre optic
cables are disconnected. Do not look directly into cables
with or without the use of any optical aids. Radiation can
come from either the data in/out connectors or
unterminated fibre optic cables connected to data in/out
connectors.
CAUTION An earthing wrist strap must be worn when handling digital
modules. An ESP earthing connection point is provided
above the leftmost PSM.
1. If the faulty digital module is still partially functional, due to no redundancy
option, inform the OMC-R before proceeding.
2. Locate the faulty module, as shown in Figure 2-13.
3. Note location of any fibre optic cable connections to the module, (MCUF or
FMUX modules only), to enable correct reconnection to the replacement
module.
4. Disconnect each fibre optic cable by gently pushing the knurled connector
in and rotating it through a quarter-turn anticlockwise to disengage, then
withdraw the cable carefully.
NOTE
It is advisable to protect the tips of the fibre optic cables
with a protective cover and secure the cables to one side.
5. Unseat the module by gripping the upper and lower pair of ejectors
between the thumb and first finger of each hand, then gently squeeze and
pull on the ejectors until the module unclips at the top and bottom of the
front panel and unplugs from the rear connector.
6. Carefully slide the module from its location and place it in an anti-static
storage container.