Lenovo ThinkPad T400s 2823 Hardware Maintenance Manual

Contents

Use the following strategy to prevent unnecessary expense for replacing andservicing FRUs:v If you are instructed to replace a FRU but the replacement does not correct theproblem, reinstall the original FRU before you continue.v Some computers have both a processor board and a system board. If you areinstructed to replace either the processor board or the system board, andreplacing one of them does not correct the problem, reinstall that board, andthen replace the other one.v If an adapter or a device consists of more than one FRU, any of the FRUs maybe the cause of the error. Before replacing the adapter or device, remove theFRUs, one by one, to see if the symptoms change. Replace only the FRU thatchanged the symptoms.Attention: The setup configuration on the computer you are servicing may havebeen customized. Running Automatic Configuration may alter the settings. Notethe current configuration settings (using the View Configuration option); then,when service has been completed, verify that those settings remain in effect.Strategy for replacing a hard disk driveAlways try to run a low-level format before replacing a hard disk drive. This willcause all customer data on the hard disk to be lost. Be sure that the customer has acurrent backup of the data before doing this task.Attention: The drive startup sequence in the computer you are servicing mayhave been changed. Be extremely careful during write operations such as copying,saving, or formatting. If you select an incorrect drive, data or programs can beoverwritten.Important notice for replacing a system boardSome components mounted on a system board are very sensitive. Improperhandling of a system board can cause damage to those components, and maycause a system malfunction.Attention: When handling a system board:v Do not drop a system board or apply any excessive force to it.v Avoid rough handling of any kind.v Avoid bending a system board and hard pushing to prevent cracking at eachBGA (Ball Grid Array) chipset.How to use error messageUse the error codes displayed on the screen to diagnose failures. If more than oneerror code is displayed, begin the diagnosis with the first error code. Whatevercauses the first error code may also cause false error codes. If no error code isdisplayed, see whether the error symptom is listed in the Symptom-to-FRU Indexfor the computer you are servicing.40 ThinkPad T400s Hardware Maintenance Manual