Siemens 3PCI Series, Operation Manual

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Troubleshooting 3PCI SCR Power Controller Series Manual
5-2
s
Version 1.2 (19000325)
ESD Sensitive Equipment!
Always be aware of electrostatic discharge (ESD) when working near or touching 3PCI
components. Printed circuit boards contain components that are sensitive to static electricity.
Handling and servicing of components that are sensitive to ESD should be done only by qualified
personnel and only after reading and understanding proper ESD techniques. The following ESD
guidelines should be followed. Following these rules can greatly reduce the possibility of ESD
damage to PC board components.
•
Make certain that anyone handling the 3PCI printed circuit boards is
wearing a properly grounded static strap. The wrist strap should be connected to ground
through a 1 megohm resistor. Grounding kits are available commercially through most
electronic wholesalers.
•
Static charge buildup can be removed from a conductive object by touching the object to a
properly grounded piece of metal.
•
Always transport static sensitive equipment in antistatic bags or along static shielding
rails. A part that is completely installed on a board does not make the part static-safe.
•
When handling a PC board, always hold the card by its edges.
•
Do not slide printed circuit boards across any surface (e.g., a table or work bench). If possible,
perform PCB maintenance at a workstation that has a conductive covering which is grounded
through a 1 megohm resistor. If a conductive tabletop cover is unavailable, a clean steel or
aluminum tabletop is an excellent substitute.
•
Avoid plastic, Styrofoam
™
, vinyl and other non-conductive materials. They are excellent static
generators and do not give up their charge easily.
•
Always use a soldering iron that has a grounded tip. Also, use either a metallic vacuum-style
plunger or copper solder removal braid when desoldering.
•
When returning components to
s LD R
, always use static-safe packing.
This limits any further component damage due to ESD.
5.4. Environmental Problems
Many reported problems with the 3PCI are the result of environmental issues. Below is a list of common
environmental problems that may cause problems with the operation of the 3PCI. Ensure that none of the
following environmental problems exist.
•
Inadequate cooling
•
Contamination
•
High ambient temperatures
•
Excessive vibration.
5.4.1. Inadequate Cooling
For models with separate power and trigger modules, allow at least an inch of air space (in any direction)
between the heat sinks and any item or structure near the 3PCI power modules. Heat sink fins should be
free of dust or dirt for proper heat transfer, and free of obstructions which could prevent proper airflow.
5.4.2. Contamination
The unit should be periodically cleaned of all dust and dirt. However, certain kinds of dust or particles are
particularly conductive. A small accumulation of conductive material can cause component failures from
arcing or complete shorts.
5.4.3. High Ambient Temperature
Lack of a proper ambient-temperature check before installation, or an increase in ambient temperature, can
result in numerous problems. Check the ambient temperature under existing conditions. If it is 122°F (50°C)
or lower, ambient temperature should not be a problem. If it is above 122°F (50°C), steps should be taken to