GRASS VALLEY 1200, Installation And Service

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4-2
Section 4 Ñ Maintenance
Overview
NOTE:
Torx-head screws are used in the manufacture of many mechanical
components on this equipment. You should have a set of Torx-head screwdrivers
(including sizes T-10 through T-30) available before attempting any mechanical
disassembly and reassembly operations.
Servicing Precautions
CAUTION
Do not operate the signal processor frame with its doors open for an extended
period of time. Failure to observe this precaution may result in overheating of
components.
Powering Down
Most maintenance operations on the Model 1200 switching system
recommend that you to turn equipment power off before making repairs to
or removing circuit modules and assemblies. Refer to System Power Down
Procedure text on page 4-16 of this manual.
WARNING
Unless specifically directed to do otherwise by a maintenance
procedure, turn power off before removing or repairing any circuit
module or assembly in this system.
Before working on any power supply assembly, turn off the power
and disconnect the power cord from the AC power source.
NOTE:
When power to the signal processor frame is turned off, all data stored in
volatile Dynamic Random Access Memory (DRAM) is lost. E-MEM data will be
retained since it is stored in battery-backed Static Random Access Memory
(SRAM), which can retain data for several years without power.
Removing any of the mezzanine modules from the Controller module results in
complete data loss from the battery-backed SRAM on the submodule removed. This
occurs because the batteries supplying power to the submodule are located on the
main Controller circuit module and not on the submodule.