hit counter script
Dell ChengMing 3991 Service Manual
  1. Manuals
  2. Brands
  3. Dell Manuals
  4. Desktop
  5. ChengMing 3991
  6. Service manual
Dell ChengMing 3991 Service Manual

Dell ChengMing 3991 Service Manual

Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual
ChengMing 3991
Service Manual
Regulatory Model: D20M
Regulatory Type: D20M005
August 2021
Rev. A01

Advertisement

Table of Contents
loading

Related Manuals for Dell ChengMing 3991

Summary of Contents for Dell ChengMing 3991

  • Page 1 ChengMing 3991 Service Manual Regulatory Model: D20M Regulatory Type: D20M005 August 2021 Rev. A01...
  • Page 2 A WARNING indicates a potential for property damage, personal injury, or death. © 2020 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other trademarks are trademarks of Dell Inc. or its subsidiaries. Other trademarks may be trademarks of their respective owners.

  • Page 3: Table Of Contents

    Contents Chapter 1: Working on your computer................... 5 Safety instructions................................5 Before working inside your computer........................5 Safety precautions................................ 6 Electrostatic discharge—ESD protection........................7 ESD field service kit ..............................7 Transporting sensitive components.......................... 8 After working inside your computer..........................8 Chapter 2: Technology and components..................9 USB features..................................
  • Page 4 Removing the system board............................. 46 Installing the system board............................48 Chapter 4: Troubleshooting......................51 EC Diag LED Behavior ..............................51 Dell Enhanced Pre-Boot System Assessment — ePSA Diagnostic 3.0...............52 System error messages..............................53 Recovering the operating system..........................53 Real-Time Clock (RTC Reset)............................53 Backup media and recovery options..........................54...

  • Page 5: Chapter 1: Working On Your Computer

    Damage due to servicing that is not authorized by Dell is not covered by your warranty. Read and follow the safety instructions that came with the product.

  • Page 6: Safety Precautions

    Standby power Dell products with standby power must be unplugged before you open the case. Systems that incorporate standby power are essentially powered while turned off. The internal power enables the system to be remotely turned on (wake on LAN) and suspended into a sleep mode and has other advanced power management features.

  • Page 7: Electrostatic Discharge-Esd Protection

    ESD protection is an increasing concern. Due to the increased density of semiconductors used in recent Dell products, the sensitivity to static damage is now higher than in previous Dell products. For this reason, some previously approved methods of handling parts are no longer applicable.

  • Page 8: Transporting Sensitive Components

    It is recommended that all field service technicians use the traditional wired ESD grounding wrist strap and protective anti-static mat at all times when servicing Dell products. In addition, it is critical that technicians keep sensitive parts separate from all insulator parts while performing service and that they use anti-static bags for transporting sensitive components.

  • Page 9: Chapter 2: Technology And Components

    Technology and components Topics: • USB features • HDMI 1.4- HDMI 2.0 USB features Universal Serial Bus, or USB, was introduced in 1996. It dramatically simplified the connection between host system units and peripheral devices like mouses, keyboards, external drivers, and printers. Table 1.

  • Page 10: Hdmi 1.4- Hdmi 2.0

    HDMI 1.4- HDMI 2.0 This topic explains the HDMI 1.4/2.0 and its features along with the advantages. HDMI (High-Definition Multimedia Interface) is an industry-supported, uncompressed, all-digital audio/video interface. HDMI provides an interface between any compatible digital audio/video source, such as a DVD player, or A/V receiver and a compatible digital audio and/or video monitor, such as a digital TV (DTV).

  • Page 11: Chapter 3: Disassembly And Reassembly

    Disassembly and reassembly Topics: • Cover • Front Bezel • Hard drive • Fan assembly • Optical drive • M.2 SSD card • Power supply unit • Speaker • Heat sink assemblyassembly • Memory modules • Expansion card • WLAN module •...
  • Page 12 Steps To remove the cover: a. Loosen the two (#6-32) captive screws that secure the cover to the computer. b. Slide the cover towards the back of your computer. Disassembly and reassembly...

  • Page 13: Installing The Cover

    Installing the cover About this task The following image indicates the location of the side cover and provides a visual representation of the installation procedure. Steps 1. Align the side cover with the guide lines on the chassis. 2. Slide the side cover towards the back of the system to install. Disassembly and reassembly...

  • Page 14: Front Bezel

    3. Replace the thumbscrew (6x32) to secure the side cover to the system. 4. Follow the procedure in After working inside your computer. Front Bezel Removing the front bezel Prerequisites 1. Follow the procedure in Before working inside your computer. 2.

  • Page 15: Installing The Front Bezel

    Installing the front bezel Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the front bezel and provides a visual representation of the installation procedure. Steps 1.

  • Page 16: Hard Drive

    Hard drive 2.5 inch hard drive Removing the 2.5 inch hard drive Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the side cover About this task The following images indicate the location of the side cover and provide a visual representation of the removal procedure. Steps 1.
  • Page 17 3. Press the release tabs on the hard-drive assembly and slide it towards the front of the system to disconnect it from the connector on the system board [2] 4. Slide [3] and lift the hard drive away from the computer [4]. Removing the hard-drive bracket Prerequisites 1.
  • Page 18 3. Loosen the two M3 x 3.5 screws from the second 2.5 inch hard-drive [3]. 4. Lift the hard-drive out of the bracket [4]. Installing the hard-drive bracket About this task Steps 1. Place the second 2.5 inch hard-drive into the bracket [1]. 2.
  • Page 19 2. Install the side cover. 3. Install the front bezel 4. Follow the procedure in After working inside your computer. Installing the 2.5 inch hard drive About this task Steps 1. Insert the 2.5 inch hard drive into the slot on the computer [1]. 2.

  • Page 20: 3.5 Inch Hard Drive

    3.5 inch hard drive Removing the 3.5 inch hard drive Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the side cover. 3. Remove the front bezel. About this task Steps To remove the 3.5 inch hard drive: a.

  • Page 21: Fan Assembly

    Installing the 3.5 inch hard drive About this task Steps 1. Insert the 3.5 inch hard drive into the slot on the computer. 2. Tighten the two screws(6-32xL3.6) to secure the hard drive to the computer. 3. Connect the hard drive data cable and power cable to the hard drive. Next steps Next steps 1.

  • Page 22: Installing The Fan Assembly

    Steps 1. Press the blue tabs on both sides of the fan, and slide to lift the fan to release it from the system. 2. Turn the fan assembly over. 3. Disconnect the fan cable from the connector on the system board. Lift the fan assembly out of the system. Installing the fan assembly About this task The following images indicate the location of the fan assembly and provide a visual representation of the removal procedure.

  • Page 23: Optical Drive

    Steps 1. Connect the fan cable to the connector on the system board. 2. Turn the fan assembly over. 3. Press the release tab on the fan assembly and place it on the system until it clicks into place. Next steps Next steps 1.
  • Page 24 Steps 1. To remove the optical drive: 2. Disconnect the optical drive data and the power cable from the optical drive [1]. 3. Remove the bracket that secure the optical drive to the computer [2]. 4. Pull the optical drive out of the computer [3]. Disassembly and reassembly...

  • Page 25: Installing The Optical Drive

    Installing the optical drive About this task Steps 1. Insert the optical drive into the slot on the computer. 2. Replace the metal bracket to secure the optical drive to the computer. 3. Connect the optical drive data cable and power cable to the optical drive. Next steps Next steps 1.
  • Page 26 About this task Steps 1. To remove the M.2 PCIe SSD: 2. Remove the screw (M2 x 3.5) that secures the M.2 SSD card to the system board [1]. 3. Slide and lift the SSD from the system [2]. Disassembly and reassembly...

  • Page 27: Installing The M.2 Ssd Card

    Installing the M.2 SSD card About this task Steps 1. Slide the M.2 2230 SSD card into the connector on the system board. 2. Replace the screw (M2 x 3.5) to secure the M.2 SSD card to the system board. Next steps Next steps 1.
  • Page 28 Disassembly and reassembly...
  • Page 29 Steps 1. To disconnect the cables: 2. Disconnect the power cables from the system board and unroute them from the routing guides on the chassis 3. Remove the three (#6-32) screws that secure the power-supply unit to the chassis. 4. Press the securing clip and slide the power-supply unit away from the back of the chassis. 5.

  • Page 30: Installing The Power Supply Unit

    Installing the power supply unit About this task Disassembly and reassembly...

  • Page 31: Speaker

    Steps 1. Slide the power-supply unit into the chassis until the securing tab snaps into position. 2. Replace the three screws (#6-32) that secure the power-supply unit to the chassis.. 3. Route the power cable through the routing guides on the chassis and connect the power cables to their respective connectors on the system board.
  • Page 32 About this task speaker Steps 1. To remove the speaker: 2. Disconnect the speaker cable from system board [1]. 3. Press the securing tab on the speaker and remove the speaker from the chassis [2]. Disassembly and reassembly...

  • Page 33: Installing The Speaker

    Installing the speaker About this task Steps 1. Slide the speaker module into the slot. 2. Connect the speaker cable to the system board. Next steps Next steps 1. Install the front bezel. 2. Install the side cover. 3. Follow the procedure in After working inside your computer.
  • Page 34 Steps 1. To remove the heat sink assembly: 2. Disconnect the cable from the connector on the system board. 3. Loosen the captive screws in a sequential order [4,3,2,1]. NOTE: Remove the screws that secure the heat sink to the system board in the order of the callouts shown . 4.

  • Page 35: Installing The Heat Sink Assembly

    Installing the heat sink assembly About this task Steps 1. Align the heat sink assembly with screw holders and place the heat sink assembly on the system board. 2. Tighten the captive screws in a to secure the heat sink assembly to the system board . NOTE: Tighten the screws on the system board in the order of the callout numbers [1, 2, 3, 4].
  • Page 36 2. Remove the side cover. About this task Steps 1. To remove the memory module: 2. Pull the securing clips from both side of the memory module until the memory module pops up. 3. Slide and remove the memory module from the memory-module slot Disassembly and reassembly...

  • Page 37: Installing The Memory Module

    Installing the memory module About this task Steps Align the memory module with the connector on the system board [1] and nsert the memory module into the memory module socket until the clips secure the memory module. Next steps Next steps 1.
  • Page 38 Steps 1. To remove the expansion card: 2. Pull the metal card-retension latch from the computer [1]. 3. Push the release tab [2] and lift the expansion card from the system board [3] . Disassembly and reassembly...

  • Page 39: Installing The Expansion Card

    Installing the expansion card About this task Steps 1. Insert the expansion card in the connector on the system board and press down until it is secured [1]. 2. Push the PCI bracket back to its position [2]. 3. Pull and close PCI bracketmetal card-retension latch to the computer [3]. Next steps Next steps 1.

  • Page 40: Wlan Module

    WLAN module Removing the WLAN module Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the side cover. About this task The following images indicate the location of the WLAN module and provide a visual representation of the removal procedure. Steps 1.

  • Page 41: Installing The Wlan Module

    Installing the WLAN module About this task Steps 1. Connect the antenna cables to the WLAN card [1] 2. Place the WLAN card bracket to secure the antenna cables [2] 3. Align the notch on the WLAN card with the tab on the WLAN card slot. Insert the WLAN card into the connector on the system board [3] 4.

  • Page 42: Coin-Cell Battery

    Coin-cell battery Removing the coin cell battery Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the side cover. About this task The following images indicate the location of the coin cell battery and provide a visual representation of the removal procedure. Steps 1.

  • Page 43: Installing The Coin Cell Battery

    Installing the coin cell battery About this task Steps 1. Insert the coin cell battery with the "+" sign facing up and slide it under the securing tabs at the positive side of the connector . 2. Press the battery into the connector until it locks into place. Next steps Next steps 1.
  • Page 44 Steps 1. To remove the processor: 2. Press the release lever down and then move it outward to release it from the retention hook [1]. 3. Lift the processor cover and remove the processor from the socket. Place it in an antistatic bag [3]. Disassembly and reassembly...

  • Page 45: Installing The Processor

    Installing the processor About this task Steps 1. Insert the processor in the processor socket. Ensure the processor is properly seated [1]. CAUTION: Do not use force to seat the processor. When the processor is positioned correctly, it engages easily into the socket. 2.

  • Page 46: System Board

    System board Removing the system board Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the side cover. 3. Remove the front bezel 4. Remove the M.2 SSD card 5. Remove the heat sink assembly 6. Remove the 7.
  • Page 47 Steps 1. Lift the hard drive caddy support away from the system board 2. Remove the eight screws (6-32xL6.35) and one standoff screw (6-32xL4.8) that secure the system board to the computer [1]. 3. Push the system board towards the front of the system Disassembly and reassembly...

  • Page 48: Installing The System Board

    4. Lift the system board away from the chassis Installing the system board About this task Disassembly and reassembly...
  • Page 49 Steps 1. Align and lower the system board into the system until the connectors at the back of the system board align with the slots on the chassis, and the screw holes on the system board align with the standoffs on the system 2.
  • Page 50 Next steps Next steps 1. Install the processor 2. Install the coin cell battery 3. Install the 4. Install the memory module 5. Install the expansion card 6. Install the heat sink assembly 7. Install the M.2 SSD card 8. Install the front bezel 9.

  • Page 51: Chapter 4: Troubleshooting

    Troubleshooting Topics: • EC Diag LED Behavior • Dell Enhanced Pre-Boot System Assessment — ePSA Diagnostic 3.0 • System error messages • Recovering the operating system • Real-Time Clock (RTC Reset) • Backup media and recovery options • WiFi power cycle...

  • Page 52: Dell Enhanced Pre-Boot System Assessment - Epsa Diagnostic 3.0

    ECI message • If problem persists, replace the system board Dell Enhanced Pre-Boot System Assessment — ePSA Diagnostic 3.0 You can invoke the ePSA diagnostics by either of the following ways : ● Press the F12 key when the system posts and choose ePSA or Diagnostics option on One Time Boot Menu.

  • Page 53: System Error Messages

    It enables you to diagnose hardware issues, repair your computer, back up your files, or restore your computer to its factory state. You can also download it from the Dell Support website to troubleshoot and fix your computer when it fails to boot into their primary operating system due to software or hardware failures.

  • Page 54: Backup Media And Recovery Options

    Backup media and recovery options It is recommended to create a recovery drive to troubleshoot and fix problems that may occur with Windows. Dell proposes multiple options for recovering Windows operating system on your Dell PC. For more information. see...

  • Page 55: Chapter 5: Getting Help And Contacting Dell

    Getting help and contacting Dell Self-help resources You can get information and help on Dell products and services using these self-help resources: Table 4. Self-help resources Self-help resources Resource location Information about Dell products and services www.dell.com My Dell app...

This manual is also suitable for:

D20m

Table of Contents