ADC HMS-318 Circuit Card Preventive Measures, Handling Circuit Cards, Storing Circuit Cards

Appendix C

CIRCUIT CARD PREVENTIVE MEASURES

This appendix describes the preventive measures that should be observed for the following:

•Handling and storing of circuit cards.

•Installing/replacing circuit cards sensitive to static electricity.

HANDLING CIRCUIT CARDS

Damage to circuit cards, particularly those that are sensitive to static electricity, may occur at any time. Follow these safeguards when handling circuit cards.

•Avoid dropping a circuit card.

•Hold circuit card by ejector tabs or card edges; avoid handling components or the connector pins.

•Avoid unnecessary removal and insertion of circuit cards. Contact life is reduced by repeated removals and insertions.

•Avoid touching circuit card contacts. Handling leaves dirt and grease, causing unit failure and reduced contact life.

•Wear a properly grounded antistatic discharge strap when handling circuit cards that are sensitive to static electricity. This strap consists of an expandable wrist strap and grounding cord; its function is to rapidly dissi- pate charges to ground.

•Periodically check the resistance value of the antistatic discharge wrist strap. The resistance measurement should be between 1 and 10 Mohms.

Note: Alternate grounding methods can be used; for example, conductive carpet, conductive shoes, or heel grounders.

STORING CIRCUIT CARDS

Spare circuit cards must be left in the original shipping container until required. To prevent damage to circuit cards while they are in storage, the following necessary precautions must be observed:

•Store circuit card in a dust-free environment. Dust particles will scratch the circuit card contacts when inserted in a connector.

•Store circuit card in a dry environment at room temperature. Excessive heat will cause the circuit card to warp.

•Place circuit card in shipping container (if available) after removal. Otherwise, carefully place circuit card in a static-shielding protective bag.

INSTALLATION/REPLACEMENT

To prevent electrostatic damage, the following conditions apply during the installation/replacement of circuit cards that are sensitive to static electricity:

•All circuit cards must be enclosed in static-shielding protective bags for transportation to and from the location.

•Upon installation/replacement, installers must wear a properly grounded antistatic discharge wrist strap.

Note: Whenever possible use the original static-shielding bag, padding, and box in which the circuit card was received. If the original material was lost, use suitable packing.

LTPH-UM-1261-01 C-1