Central Processor Unit Led Display; Replacing Cpu Circuit Pack - Nortel DMS-100 Series Manual

2-2 Central Processor Unit (CPU) circuit pack (NT6M62BA)

Central processor unit LED display

The CPU circuit pack contains a seven-segment display Light Emitting Diode
(LED) that provides a visual display of error control status. Five hardware
status lines are decoded to display CPU fault conditions. The display also
contains a decimal point feature that provides a visual display of the CPU
clock. See Table 2-1.
Output to the display must occur within 0.5 seconds for the display to remain
valid. This time frame is compatible with the 0.5 second status request time
interval of the error control circuit pack. The data byte and hardware status
lines are decoded by an Erasable Programmable Read Only Memory
(EPROM). Output conditions may appear as shown in Table 2-2.
There are various option settings on this circuit pack. See Table 2-3. Figure
2-1 shows the option locations and circuit pack layout.

Replacing CPU circuit pack

To replace the CPU circuit pack, use the following procedure.
Procedure 2-1
Replacing CPU circuit pack (NT6M62BA) - slot 1
Step Description
CAUTION
Since all DPP circuit packs are static sensitive, be careful when handling them.
Wear a wrist grounding strap when working with the DPP.
WARNING
Since the DPP is powered up during this procedure, observe all safety procedures
for operations on live equipment.
6
To remove the front panel of the DPP, loosen the four screws located on the left and
right hand sides. Once removed, put the front panel in a safe place to avoid damage,
bending and scratching.
7
Get the replacement circuit pack from the spares kit.
8
Remove the protective electrostatic bag and place it on a suitable, grounded surface.
297-1001-539 Standard 01.03 September 2000
Sheet 1 of 4