Precautions When Servicing; Damage Due To Electrostatic Discharge - Canon LASER CLASS 3175 Service Manual

LASER CLASS 3170/3175/3175MS Chapter 1: Safety and Precautions

2.3 Precautions when Servicing

2.3.1 Damage due to electrostatic discharge

This fax contains contact sensor and printed circuit boards that use many
electrical components such as ROM, RAM and custom ICs. A static charge can
damage these components, so, care must be taken to prevent damage caused by
electrostatic discharge when disassembling the fax.
Static electricity
Electrostatic discharge damages electronic components and alters
their electrical characteristics. Even plastic tools and hands without
grounding wrist straps will generate enough static electricity to
damage electronic components.
The following equipment is needed to prevent electrostatic discharge damage:
• An earthed conductive mat
• Grounding wrist straps
• Alligator clip cable for earthing metal parts on the fax
Carry out the following countermeasures if the above equipment is not available,
(for example, during on-site servicing):
• Use an anti-static bag for storing or carrying printed circuit boards or electronic
devices.
• Avoid wearing silk or polyester clothing, or leather-soled shoes. Wear cotton
clothing and rubber-soled shoes.
• Avoid servicing the fax in carpeted rooms.
• Before starting servicing, touch grounded earth terminals to discharge any
static electricity charges.
• Wear grounding wrist straps, and earth metal parts on the machine.
• Handle printed circuit boards and electronic devices by their edges and
packages. Do not directly touch terminals of electronic devices with your
fingers.
Electric shock when carrying out work with the fax turned on
When you must service the fax with the power cord plugged in, you
must not ground your body with grounding wrist straps. This is to
prevent electricity passing to your body and causing electric shock.
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