Cautions For Circuit Boards - Quickie QM-7 Series Service Manual

Cautions for circuit boards

To help prevent Electro Static Discharge (ESD) the following proper
handling techniques should be followed:
ESD:
• Do not place Printed Circuit Boards or their containers near
sources of strong electrical fi elds (such as above a CRT).
•
To avoid the occurrence of static charge or discharge due to
friction, keep the Printed Circuit Boards separate from one an-
other and do not stack them directly on top of one another if not
protected by antistatic bags.
• Store each Printed Circuit Board in an antistatic bag with an
external cushioning bubble-wrap layer until assembled to
wheelchair. Antistatic bag must have metal content to protect
the printed circuit board. Gray bag protects from ESD, pink bag
or bubble wrap does not protect as well.
•
Always wear an ESD preventive wrist or ankle strap when han-
dling electronic components. Connect one end of the strap to
an ESD jack or an unpainted metal component on the system
(such as a captive installation screw).
•
Handle Printed Circuit Boards by the edges only; avoid touch-
ing the Printed Circuit Board and connector pins.
• Place any removed Printed Circuit Board on an antistatic sur-
face or in a static shielding bag.
•
Avoid contact between the Printed Circuit Boards and clothing.
The wrist strap only protects the card from ESD voltages on the
body; ESD voltages on clothing can still cause damage.
•
Make sure that the Printed Circuit Board power is off by dis-
connecting the seating harness prior to attaching or removing
printed circuit board.
Printed Circuit Board Flexing:
• The printed circuit board has surface-mount components that
may break when the board is fl exed. To minimize the amount
of board fl exing, observe the following precautions:
•
Hold the printed circuit board only by the edges.
• Do not place the printed circuit board on a hard surface.
•
Tighten board mounting screws only hand tight (torque12.4
in lbs/1.4Nm) in a cross pattern to reduce stress on mounting
holes and PCB board material.
SUNRISE MEDICAL
Section 1
QM-7 SERIES SERVICE MANUAL JANUARY 2012
PAGE 1.7