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VPAP® III, VPAP III ST, VPAP III ST-A Service Manual
4
Static Precautions
Warning
Prior to disassembly or assembly, make sure that the power is not connected to the flow
generator.
Integrated circuits (ICs) within the various PCBs can be badly damaged by electrostatic discharge
or transient voltages. The following procedures are recommended to avoid component damage:
1 Work benches where handling and repairs are done must have surfaces of suitable conducting
material connected via a 1 M
Ω
resistor to an electrical ground.
2 The area under and also in front of the work bench must be coated with a suitable conductive
floor paint, or alternatively covered with a conductive floor mat. The conductive paint coating
or floor mat must be connected to an electrical ground.
3 Soldering irons or solder baths must be at the same reference (ground) potential as the work
bench.
4 A wrist strap must be worn by service personnel working at the bench. The wrist strap must
have a conductive lead (1 M
Ω
) connected to the bench surface. Alternatively, a heel grounding
strap to ground the operator to the floor may be used. (Such a wrist or heel strap should not
create an electrical hazard for the wearer).
5 Handling of ICs should be kept to a minimum. If handling is required, avoid directly touching the
leads. The recommended procedure is to first touch the container in which the ICs are stored,
or the PCB in which they are mounted, before touching the ICs. Service personnel should take
every precaution that the items will see the same reference potential when moved.
6 All ICs and PCB assemblies containing ICs should be stored in antistatic bags until use.
7 Service personnel should wear clothing which minimizes the build up of static charges. Cotton
is preferable to wool or synthetic fibres.
8 Service personnel should avoid electrostatic build up through the movement of air over plastic
material.
9 Plastic materials should wherever possible be kept away from the ICs as they develop and
maintain high levels of static charge.
10 Low humidity increases potential static problems. Maintaining humidity levels above 60% is one
of the most effective ways to guard against static handling problems.
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