Chapter 2. Important Service Information; Strategy For Replacing Frus - Lenovo ThinkPad T420 2620 Hardware Maintenance Manual

Chapter 2. Important service information

This chapter presents following important service information that applies to all machine types supported by
this manual:
• "Strategy for replacing FRUs" on page 23
- "Strategy for replacing a hard disk drive" on page 24
- "Important notice for replacing a system board" on page 24
- "How to use error message" on page 24
• "Strategy for replacing FRUs for CTO, CMV, and GAV" on page 25
- "Product definition" on page 25
- "FRU identification for CTO, CMV, and GAV products" on page 25
Important:
UEFI BIOS and device driver fixes are customer-installable. The UEFI BIOS and device drivers are posted on the
customer support site
http://www.lenovo.com/support
System Disassembly/Reassembly videos that show the FRU removals or replacements for the Lenovo
service technicians are available in the following support site:
http://www.lenovoservicetraining.com/ion/
Advise customers to contact the Customer Support Center at 800-426-7378 if they need assistance in obtaining or
installing any software fixes, drivers, and UEFI BIOS downloads.
Customers in Canada should call the Customer Support Center at 800-565-3344 for assistance or download
information.

Strategy for replacing FRUs

Before replacing parts:
Make sure that all software fixes, drivers, and UEFI BIOS downloads are installed before replacing any
FRUs listed in this manual.
After a system board is replaced, ensure that the latest UEFI BIOS is loaded to the system board before
completing the service action.
To download software fixes, drivers, and UEFI BIOS, do as follows:
1. Go to http://www.lenovo.com/support.
2. Enter the product number of the computer or press Auto-detect button on the screen.
3. Select Downloads and drivers.
4. Follow the directions on the screen and install the necessary software.
Use the following strategy to prevent unnecessary expense for replacing and servicing FRUs:
• If you are instructed to replace a FRU but the replacement does not correct the problem, reinstall
the original FRU before you continue.
• Some computers have both a processor board and a system board. If you are instructed to replace either
the processor board or the system board, and replacing one of them does not correct the problem,
reinstall that board, and then replace the other one.
• If an adapter or a device consists of more than one FRU, any of the FRUs may be the cause of the error.
Before replacing the adapter or device, remove the FRUs, one by one, to see if the symptoms change.
Replace only the FRU that changed the symptoms.
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