Lenovo ThinkCentre M55 Hardware Maintenance Manual - Page 78

No-beep symptoms Symptom/Error No beep during POST but computer works correctly. No beep during POST. FRU/Action System board 1. See "Undetermined problems" on page 76. 2. System Board 3. Memory Module 4. Any Adapter or Device 5. Riser Card 6. Power Cord 7. Power Supply POST error codes Each time you power-on the system, it performs a series of tests that check the operation of the system and some options. This series of tests is called the Power-On Self-Test, or POST. POST does the following operations. • Checks some basic system-board operations • Checks the memory operation • Starts the video operation • Verifies that the diskette drive is working • Verifies that the hard disk drive is working If the POST finishes without detecting any problems, a single beep sounds and the first screen of the operating system or application program appears. If the POST detects a problem, an error message appears on the screen. A single problem can cause several error messages to appear. When you correct the cause of the first error message, the other error messages probably will not appear on the screen the next time you turn on the system. In the following index, X can represent any number. POST Error Code 162 Configuration error 164 Memory Size Error 166 Boot Block Check Sum Error 167 No Processor BIOS update found 175 Primary Copy of Secure Data is damaged 176 The System has been tampered with FRU/Action Select the default settings in BIOS. See Chapter 6 "Diagnostics, Test and Recovery Information" on page 47. 1. Run the Extended Memory Diagnostic tests 2. Replace memory modules 1. Perform a flash update to update the BIOS level 2. System board 1. Run Setup. Check Stepping level for the BIOS level needed, then perform the flash update. 2. Replace the microprocessor 1. Run Setup and select default settings 2. System board 1. Covers were removed from the computer 72 Hardware Maintenance Manual