Lenovo ThinkCentre A52 User Manual - Page 50

Power LED ON OFF OFF (after the power button has been pressed) ON d. Observe the LEDs and refer to the following table. Green diagnostic LED ON OFF Yellow diagnostic LED Action OFF This is the normal condition of the LEDs when the power is OK. OFF Make sure the power cord is attached to a working electrical outlet. If the electrical outlet is OK, replace the power supply. ON OFF Replace the system board ON ON Replace the power supply If the Diagnostic LEDs are in the normal condition and the problem persists, replace the system board and the microprocessor, one at a time, until the computer works correctly. 8. Run the Diagnostic programs. See Chapter 5, "Diagnostics using PC-Doctor for DOS," on page 47. v If you receive an error, replace the part that the diagnostic program calls out or go to "Diagnostic error codes" on page 59. v If the test stops and you cannot continue, replace the last device tested. Problem determination tips Due to the variety of hardware and software combinations that can be encountered, use the following information to assist you in problem determination. If possible, have this information available when requesting assistance from Service Support and Engineering functions. v Machine type and model v Processor or hard disk upgrades v Failure symptom - Do diagnostics indicate a failure? - What, when, where, single, or multiple systems? - Is the failure repeatable? - Has this configuration ever worked? - If it has been working, what changes were made prior to it failing? - Is this the original reported failure? v Diagnostics version - Type and version level v Hardware configuration - Print (print screen) configuration currently in use - BIOS level v Operating system software - Type and version level Note: To eliminate confusion, identical systems are considered identical only if they: 44 Hardware Maintenance Manual