Canon MultiPASS C50, Service Manual

Page: 62 / 272

5.3 Servicing Cautions
5.3.1 Damage from static charge
This unit contains contact sensors and printed circuit boards equipped with ROM, RAM,
custom chips, etc. These electronic components are susceptible to damage caused by static
charge.
When disassembling this unit, take care to prevent static charge.
Static electricity
Static charge can damage electronic components or alter their electrical
characteristics. Even plastic tools and hands without grounding wrist straps
can generate damaging static charge.
The following items are required to prevent static charge:
• A grounded, conductive mat
• Grounding wrist straps
• A cord with alligator clips to ground this unit’s metal chassis
If you do not have any of the above on hand (during on-site servicing), follow the alternate
measures below:
• Use a grounding bag to store and transport printed circuit boards and electronic devices.
• Avoid wearing silk or polyester clothing and leather-soled shoes. Wear cotton clothing
and rubber-soled shoes instead.
• Avoid servicing this unit in a carpeted room.
• Before servicing this unit, touch this unit’s grounded terminals to discharge any static
charge.
• Wear grounding wrist straps and ground this unit’s metal chassis.
• Always handle the circuit boards and devices along their edges. Do not touch the
components and terminals with your fingers.
Shock hazard during power on
If servicing must be performed while this unit is turned on, do not wear any
grounding wrist straps. This is to prevent electricity from passing through
your body.
5.3.2 Scanner unit
a) General Precautions
• Handle contact sensors with care to prevent scratching or smudging of the scanning
surface. Scratches or smudges can cause vertical stripes, etc., to appear on the scanned
image.
• Be careful not to scratch the ADF rollers. If the rollers are scratched, paper jams may
result.
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