Routine Maintenance; Status And Alarm Lamp Maintenance; Other Indicator Lamps - Northern Telecom DMS-100 Series Maintenance Manual

Routine maintenance

Procedures
Routine DPP system maintenance may include the following procedures:
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Status and alarm lamp maintenance

The lamps for the status and alarm indicators on the switch and status panel
are special light bar devices, composed of four light emitting diodes (LEDs)
in each lamp. Since these LEDs are individually powered, if one quadrant
fails, the remaining quadrants will continue to operate and light the
indicator.
Periodically test the Status and Alarm Lamps using the Lamp Test (LT)
rocker switch on the front of the panel. Figure 7-1 shows the status panel.

Other indicator lamps

The red or green lamp on the Winchester disk drive is an LED and is not
field replaceable.
The LED on the Error Control II PCA (slot A5), Error Control II Jumper
PCA (slot B5), and LED display on the CPU with DMA PCA (slots A1 and
B1) are components of those PCAs and are also not field replaceable.
Testing and replacing the Status and alarm lamp
Use Procedure 7-1 to test and replace the status and alarm lamp.
testing (and replacing, if necessary) the status and alarm lamps
checking other indicator lamps
checking system temperature alarms
cleaning (and replacing, if necessary) the fans
DPP Recovery and Routine Maintenance Guide BCS35 and up
7-1