Nortel Passport 15000, Hardware Installation And Maintenance, Page: 58 / 874

58 Chapter 2 Safety considerations and best practices
241-1501-240 5.2S2
Unless otherwise specified, all screws are unfastened counter-clockwise and
fastened clockwise. Some screws require a hand tool to fasten or unfasten
them (for example, an air filter cover).
Fastening captive screws
Most screws on Passport 15000 or 20000 plug-in field replaceable units
(FRUs) or service replaceable units (SRUs) are captive. A captive fastener
means the fastener stays attached to the unit after it is unfastened.
Do not use any kind of power tool on a captive screw. The screw is necessary
to keep the card, module, or cover properly seated. If the screw is
overtightened by stripping it or its hole:
• the hardware assembly that accommodates the unit will need to be
replaced (for example, a cooling unit for a fan controller or a BIP for a
BIM)
• the unit with the captive screw will need to be replaced (for example, a
fabric for its cover)
• if the unit or what it fastens to is not replaced, the hardware will not likely
operate correctly (for example, the reset button on a Passport 20000
fabric would not be engaged) and EMI containment is jeopardized
Fastening termination panels
When fastening a fanout panel or a sparing panel to a Passport 7400 cabinet,
you will need EIA screws instead of the 10-mm (3/8-inch) screws that were
provided with the sparing panel.
When fastening a Passport 15000 or 20000 fanout panel or sparing panel to a
Passport 7400 cabinet (for example, an NTQS31), you must ground the panel
by fastening a No. 6 AWG (13.3 mm
2
) cable between the screw head and the
CAUTION
Risk of equipment damage and service loss
Do not use any kind of power tool on a captive screw. The
screw is necessary to keep the card, module, or cover
properly seated. If the screw is overtightened (stripping it
or its hole), the hardware cannot operate correctly.