Lenovo 21BU Manuals

Manuals and User Guides for Lenovo 21BU. We have 1 Lenovo 21BU manual available for free PDF download: Hardware Maintenance Manual

Lenovo 21BU Hardware Maintenance Manual

Lenovo 21BU Hardware Maintenance Manual (102 pages)

Brand: Lenovo | Category: Laptop | Size: 43.22 MB

Table of Contents

Table of Contents
3
About this Manual
5
Chapter 1. Safety Information

7
Chapter 2. Important Service Information

27
Chapter 3. General Checkout

29
- What to Do First
  29
- Checkout Guide
  30
- Diagnosing Problems
  30
- Quick Test Programs
  31
- UEFI Diagnostic Program
  31
- Bootable Diagnostic Programs
  31
- Power System Checkout
  32
- Checking the Ac Power Adapter
  33
- Checking the Built-In Battery and Operational Charging
  33
- Checking the Coin-Cell Battery
  33
Chapter 4. Related Service Information

35
- Reset or Restore Windows
  35
- Passwords
  35
- Power-On Password
  35
- Nvme Passwords
  36
- Supervisor Password
  36
- System Management Password
  36
- How to Remove the Power-On Password
  37
- How to Remove the Nvme Password
  37
- How to Remove the System Management Password
  37
- Power Management
  38
- Sleep Mode
  38
- Hibernation Mode
  39
- Symptom-To-FRU Index
  39
- Numeric Error Codes
  40
- Error Messages
  41
- Beep Errors
  41
- No-Beep Symptoms
  43
- LCD-Related Symptoms
  43
- Intermittent Problems
  44
- Undetermined Problems
  44
Chapter 5. Special Keys

47
Chapter 6. Locations

49
- Locating Computer Controls and Connectors
  49
- Front
  49
- Left and Right
  50
- Rear
  51
- Bottom
  52
- Locating Frus and Crus
  53
- Major Frus and Crus
  54
- LCD Frus and Crus
  57
- Miscellaneous Parts
  59
- Connector and Cable Guide
  59
- Looking up FRU Information
  62
Chapter 7. FRU Replacement Notices

63
- Service Tool Kit
  63
- Screw Notices
  63
- Retaining Serial Numbers
  64
- Restoring the Serial Number of the System Unit
  64
- Retaining the UUID
  65
- Reading or Writing the ECA Information
  65
Chapter 8. Removing or Replacing an FRU

67
Appendix A. Notices

97
Appendix B. Abbreviation Table

99

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