User Manual

7 Maintenance
ID No: 163511 Page 33
7. MAINTENANCE
7.1. MAINTENANCE
Read the health and safety warnings in chapter 1.2 Health and Safety Warnings.
) Note: The remote unit does not require preventative maintenance
measures.
Maintenance of the MMR8L L should be performed on a FRU (Field Replaceable
Unit) basis only. Do not damage the warranty labels on the components, as this voids
the warranty.
The spare parts list contains only units that can be replaced without tuning or
soldering work.
) Note: Defect parts should only be replaced by original parts from the
supplier. All interventions inside the housing are at one’s own risk.
)
Note: During maintenance ensure that the unit has been disconnected
from mains.
To open the cabinet of the MMR8L L, observe the instructions in chapter 4.1.1
General.
) Note: Before disconnecting any cables, label any unlabeled cables to
ensure correct reconnection.
To replace an FRU, use the appropriate tools. Replacement tools may be ordered
from the supplier. All screws have a right-hand thread, turn the tool clockwise for
tightening and anti-clockwise for loosening.
SMA connectors have a specified torque of 100 Ncm. Use an appropriate tool to
fasten and unfasten these connectors. Do not over-tighten the connectors or screws.
The table below shows various screws with their respective torques.
Screw Type Tallow-drop Socket head cap Countersunk head
Thread size Specified Torque (in Ncm)
M 2.0 40 not in use 40
M 2.5 82 not in use 82
M 3.0 145 100 145
M 4.0 330 330 330
M 5.0 650 tbd. 650
table 7-1 Specified torques for various screw types
) Note: Do not forget to reinstall the front cover after the replacement
procedure to ensure safe operation.
If any FRU not contained in the following chapter needs to be replaced, contact
customer service for additional instructions.