Lenovo T420 Tablet User Manual


 
Notes:
1. Use product-specic ESD procedures when they exceed the requirements noted here.
2. Make sure that the ESD protective devices you use have been certied (ISO 9000) as fully effective.
When handling ESD-sensitive parts:
Keep the parts in protective packages until they are inserted into the product.
Avoid contact with other people.
Wear a grounded wrist strap against your skin to eliminate static on your body.
Prevent the part from touching your clothing. Most clothing is insulative and retains a charge even when
you are wearing a wrist strap.
Use a grounded work mat to provide a static-free work surface. The mat is especially useful when
handling ESD-sensitive devices.
Select a grounding system, such as those listed below, to provide protection that meets the specic
service requirement.
Note: The use of a grounding system to guard against ESD damage is desirable but not necessary.
Attach the ESD ground clip to any frame ground, ground braid, or green-wire ground.
When working on a double-insulated or battery-operated system, use an ESD common ground or
reference point. You can use coax or connector-outside shells on these systems.
Use the round ground prong of the ac plug on ac-operated computers.
Grounding requirements
Electrical grounding of the computer is required for operator safety and correct system function. Proper
grounding of the electrical outlet can be veried by a certied electrician.
4 ThinkPad T420 and T420i Hardware Maintenance Manual