• 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.
Attention: The setup conguration on the computer you are servicing may have been customized. Running
Automatic Conguration may alter the settings. Note the current conguration settings (using the View
Conguration option); then, when service has been completed, verify that those settings remain in effect.
Strategy for replacing a hard disk drive
Always try to run a low-level format before replacing a hard disk drive. This will cause all customer data on
the hard disk to be lost. Be sure that the customer has a current backup of the data before doing this task.
Attention: The drive startup sequence in the computer you are servicing may have been changed. Be
extremely careful during write operations such as copying, saving, or formatting. If you select an incorrect
drive, data or programs can be overwritten.
Important notice for replacing a system board
Some components mounted on a system board are very sensitive. Improper handling of a system board can
cause damage to those components, and may cause a system malfunction.
Attention: When handling a system board:
• Do not drop a system board or apply any excessive force to it.
• Avoid rough handling of any kind.
• Avoid bending a system board and hard pushing to prevent cracking at each BGA (Ball Grid Array) chipset.
How to use error message
Use the error codes displayed on the screen to diagnose failures. If more than one error code is displayed,
begin the diagnosis with the rst error code. Whatever causes the rst error code may also cause false error
codes. If no error code is displayed, see whether the error symptom is listed in the Symptom-to-FRU
Index for the computer you are servicing.
Strategy for replacing FRUs for CTO, CMV, and GAV
Product denition
Dynamic Congure To Order (CTO)
This provides the ability for a customer to congure a Lenovo solution from an eSite, and have this
conguration sent to fulllment, where it is built and shipped directly to the customer. The machine label,
Product Entitlement Warehouse (PEW), eSupport, and the HMM will load these products as the 4-digit MT
and 3-digit model, where model = “CTO” (Example: 1829-CTO).
Custom Model Variant (CMV)
This is a unique conguration that has been negotiated between Lenovo and the customer. A unique 4-digit
MT and 3-digit model is provided to the customer to place orders (Example: 1829-W15). A CMV is a special
bid offering. Therefore, it is NOT generally announced.
• The MTM portion of the machine label is the 4-digit MT and 3-digit model, where model = “CTO”
(Example: 1829-CTO). The PRODUCT ID portion of the machine label is the 4-digit MT and 3-digit CMV
model (Example: 1829-W15).
• The PEW record is the 4-digit MT and 3-digit model, where model = “CTO” (Example: 1829-CTO).
24 ThinkPad T520, T520i, and W520 Hardware Maintenance Manual