Lenovo ThinkCentre M90n-1 Owner's manual

M90n-1
Hardware Maintenance Manual

Third Edition (January 2021)
© Copyright Lenovo 2019, 2021.
LIMITED AND RESTRICTED RIGHTS NOTICE: I data or so tware is delivered pursuant to a General Services
Administration “GSA” contract, use, reproduction, or disclosure is subject to restrictions set orth in Contract No. GS-
35F-05925.

Contents
About thi manual . . . . . . . . . . . . iii
Chapter 1. Important afety
information. . . . . . . . . . . . . . . . 1
General sa ety . . . . . . . . . . . . . . . . 1
Electrical sa ety . . . . . . . . . . . . . . . . 2
Sa ety inspection guide. . . . . . . . . . . . . 3
Handling electrostatic discharge-sensitive
devices . . . . . . . . . . . . . . . . . . . 4
Grounding requirements . . . . . . . . . . . . 4
Sa ety notices (multi-lingual translations) . . . . . . 4
Chapter 2. Important afety
information. . . . . . . . . . . . . . . 27
Strategy or replacing FRUs . . . . . . . . . . 27
Strategy or replacing a hard disk drive or a
solid-state drive . . . . . . . . . . . . . 27
Important notice or replacing a system
board . . . . . . . . . . . . . . . . . 27
How to use error codes . . . . . . . . . . 28
Strategy or replacing FRUs or CTO, special-bid,
and standard models. . . . . . . . . . . . . 28
Product de inition . . . . . . . . . . . . 28
FRU identi ication . . . . . . . . . . . . 28
Chapter 3. Product overview . . . . . 29
Top . . . . . . . . . . . . . . . . . . . 29
Front . . . . . . . . . . . . . . . . . . . 29
Rear . . . . . . . . . . . . . . . . . . . 29
Bottom . . . . . . . . . . . . . . . . . . 30
Le t . . . . . . . . . . . . . . . . . . . 30
Chapter 4. Service checkout and
ymptom-to-FRU index . . . . . . . . 31
Service checkout . . . . . . . . . . . . . . 31
Problem determination tips . . . . . . . . 31
Symptom-to-FRU index . . . . . . . . . . . 32
Hard disk drive boot error . . . . . . . . . 32
Power supply problems . . . . . . . . . . 33
Beep symptoms . . . . . . . . . . . . . 33
POST error codes . . . . . . . . . . . . 34
Miscellaneous error conditions . . . . . . . 35
Undetermined problems . . . . . . . . . 37
Chapter 5. Trouble hooting,
diagno tic , and recovery . . . . . . . 39
Basic procedure or resolving computer
problems . . . . . . . . . . . . . . . . . 39
Troubleshooting . . . . . . . . . . . . . . 39
Startup problems . . . . . . . . . . . . 40
Audio problems . . . . . . . . . . . . . 41
Network problems . . . . . . . . . . . . 41
Per ormance problems . . . . . . . . . . 44
Storage drive problems . . . . . . . . . . 45
Serial connector problems . . . . . . . . . 45
USB device problems . . . . . . . . . . 45
So tware problems. . . . . . . . . . . . 46
Diagnostics . . . . . . . . . . . . . . . . 46
Lenovo diagnostic tools . . . . . . . . . . 46
UEFI diagnostic program . . . . . . . . . 46
Recovery . . . . . . . . . . . . . . . . . 47
Restore system iles and settings to an earlier
point . . . . . . . . . . . . . . . . . 47
Restore your iles rom a backup . . . . . . 47
Reset your computer . . . . . . . . . . . 47
Use advanced options . . . . . . . . . . 47
Windows automatic recovery. . . . . . . . 47
Create and use a recovery USB device . . . . 48
Update the device driver . . . . . . . . . 48
Chapter 6. Hardware removal and
in tallation . . . . . . . . . . . . . . . 51
Handling static-sensitive devices . . . . . . . . 51
Service tool kit . . . . . . . . . . . . . . . 51
Major FRUs and CRUs . . . . . . . . . . . . 52
System board . . . . . . . . . . . . . . . 54
Removing and installing hardware . . . . . . . 54
External options . . . . . . . . . . . . . 54
Power adapter and power cord . . . . . . . 55
Heat sink cover . . . . . . . . . . . . . 57
DIN rail bracket kit . . . . . . . . . . . . 58
VESA mount bracket . . . . . . . . . . . 60
Power adapter bracket . . . . . . . . . . 62
Rear Wi-Fi antenna. . . . . . . . . . . . 65
Wireless WAN antenna . . . . . . . . . . 66
Bottom cover . . . . . . . . . . . . . . 67
M.2 solid-state drives. . . . . . . . . . . 69
Wi-Fi card . . . . . . . . . . . . . . . 70
Wireless WAN card . . . . . . . . . . . 71
System board and coin-cell battery . . . . . 74
Le t cover and ront Wi-Fi antenna cable . . . 76
Rear Wi-Fi antenna cable . . . . . . . . . 77
Right cover and ront wireless WAN antenna
cable . . . . . . . . . . . . . . . . . 78
Rear wireless WAN antenna cable . . . . . . 80
Internal speaker . . . . . . . . . . . . . 81
© Copyright Lenovo 2019, 2021 i

Heat sink . . . . . . . . . . . . . . . 83 Chapter 7. Notice and
trademark . . . . . . . . . . . . . . . 85
ii M90n-1 Hardware Maintenance Manual

About thi manual
This manual provides service and re erence in ormation or ThinkCentre® computers listed on the ront cover.
Illustrations in this manual might look di erent rom your product.
Use this manual along with the advanced diagnostic tests to troubleshoot problems.
Important: This manual is intended only or trained service technicians who are amiliar with ThinkCentre
computers. Use this manual along with the advanced diagnostic tests to troubleshoot problems e ectively.
Be ore servicing a ThinkCentre computer, be sure to read and understand Chapter 2 “Important sa ety
in ormation” on page 27.
© Copyright Lenovo 2019, 2021 iii

iv M90n-1 Hardware Maintenance Manual

Chapter 1. Important afety information
General afety
Follow these rules to ensure general sa ety:
• Observe good housekeeping in the area o the machines during and a ter maintenance.
• When li ting any heavy object:
1. Ensure you can stand sa ely without slipping.
2. Distribute the weight o the object equally between your eet.
3. Use a slow li ting orce. Never move suddenly or twist when you attempt to li t.
4. Li t by standing or by pushing up with your leg muscles; this action removes the strain rom the
muscles in your back.
Attention: Do not attempt to li t any objects that weigh more than 16 kg (35 lb) or objects that you
think are too heavy or you.
• Do not per orm any action that causes hazards to the customer, or that makes the equipment unsa e.
• Be ore you start the machine, ensure that other service representatives and the customer's personnel are
not in a hazardous position.
• Place removed covers and other parts in a sa e place, away rom all personnel, while you are servicing the
machine.
• Keep your tool case away rom walk areas so that other people will not trip over it.
• Do not wear loose clothing that can be trapped in the moving parts o a machine. Ensure that your sleeves
are astened or rolled up above your elbows. I your hair is long, asten it.
• Insert the ends o your necktie or scar inside clothing or asten it with a nonconductive clip, approximately
8 centimeters (3 inches) rom the end.
• Do not wear jewelry, chains, metal- rame eyeglasses, or metal asteners or your clothing.
Remember: Metal objects are good electrical conductors.
• Wear sa ety glasses when you are: hammering, drilling, soldering, cutting wire, attaching springs, using
solvents, or working in any other conditions that might be hazardous to your eyes.
• A ter service, reinstall all sa ety shields, guards, labels, and ground wires. Replace any sa ety device that
is worn or de ective.
• Reinstall all covers correctly be ore returning the machine to the customer.
CAUTION:
Keep finger and other part of your body away from hazardou , moving part . If you uffer an injury,
eek medical care immediately.
CAUTION:
Avoid contact with hot component in ide the computer. During operation, ome component
become hot enough to burn the kin. Before you open the computer cover, turn off the computer,
di connect power, and wait approximately 10 minute for the component to cool.
© Copyright Lenovo 2019, 2021 1

Electrical afety
CAUTION:
Electrical current from power, telephone, and communication cable can be hazardou . To avoid
per onal injury or equipment damage, di connect the attached power cord , telecommunication
y tem , network , and modem before you open the computer cover , unle in tructed otherwi e
in the in tallation and configuration procedure .
Observe the ollowing rules when working on electrical equipment.
Important: Use only approved tools and test equipment. Some hand tools have handles covered with a so t
material that does not insulate you when working with live electrical currents. Many customers have, near
their equipment, rubber loor mats that contain small conductive ibers to decrease electrostatic discharges.
Do not use this type o mat to protect yoursel rom electrical shock.
• Find the room emergency power-o (EPO) switch, disconnecting switch, or electrical outlet. I an electrical
accident occurs, you can then operate the switch or unplug the power cord quickly.
• Do not work alone under hazardous conditions or near equipment that has hazardous voltages.
• Disconnect all power be ore:
– Per orming a mechanical inspection
– Working near power supplies
– Removing or installing Field Replaceable Units (FRUs)
• Be ore you start to work on the machine, unplug the power cord. I you cannot unplug it, ask the customer
to power-o the wall box that supplies power to the machine and to lock the wall box in the o position.
• I you need to work on a machine that has exposed electrical circuits, observe the ollowing precautions:
– Ensure that another person, amiliar with the power-o controls, is near you.
Remember: Another person must be there to switch o the power, i necessary.
– Use only one hand when working with powered-on electrical equipment; keep the other hand in your
pocket or behind your back.
Remember: There must be a complete circuit to cause electrical shock. By observing the above rule,
you may prevent a current rom passing through your body.
– When using a tester, set the controls correctly and use the approved probe leads and accessories or
that tester.
– Stand on suitable rubber mats (obtained locally, i necessary) to insulate you rom grounds such as
metal loor strips and machine rames.
Observe the special sa ety precautions when you work with very high voltages; these instructions are in
the sa ety sections o maintenance in ormation. Use extreme care when measuring high voltages.
• Regularly inspect and maintain your electrical hand tools or sa e operational condition.
• Do not use worn or broken tools and testers.
• Never assume that power has been disconnected rom a circuit. First, check that it has been powered-o .
• Always look care ully or possible hazards in your work area. Examples o these hazards are moist loors,
nongrounded power extension cables, power surges, and missing sa ety grounds.
• Do not touch live electrical circuits with the re lective sur ace o a plastic dental mirror. The sur ace is
conductive; such touching can cause personal injury and machine damage.
2M90n-1 Hardware Maintenance Manual

• Do not service the ollowing parts with the power on when they are removed rom their normal operating
places in a machine:
– Power supply units
– Pumps
– Blowers and ans
– Motor generators
and similar units. (This practice ensures correct grounding o the units.)
• I an electrical accident occurs:
– Use caution; do not become a victim yoursel .
– Switch o power.
– Send another person to get medical aid.
Safety in pection guide
The intent o this inspection guide is to assist you in identi ying potentially unsa e conditions on these
products. Each machine, as it was designed and built, had required sa ety items installed to protect users
and service personnel rom injury. This guide addresses only those items. However, good judgment should
be used to identi y potential sa ety hazards due to attachment o eatures or options not covered by this
inspection guide.
I any unsa e conditions are present, you must determine how serious the apparent hazard could be and
whether you can continue without irst correcting the problem.
Consider these conditions and the sa ety hazards they present:
• Electrical hazards, especially primary power (primary voltage on the rame can cause serious or atal
electrical shock).
• Explosive hazards, such as a damaged CRT ace or bulging capacitor
• Mechanical hazards, such as loose or missing hardware
The guide consists o a series o steps presented in a checklist. Begin the checks with the power o , and the
power cord disconnected.
Checklist:
1. Check exterior covers or damage (loose, broken, or sharp edges).
2. Power-o the computer. Disconnect the power cord.
3. Check the power cord or:
a. A third-wire ground connector in good condition. Use a meter to measure third-wire ground
continuity or 0.1 ohm or less between the external ground pin and rame ground.
b. The power cord should be the appropriate type as speci ied in the parts listings.
c. Insulation must not be rayed or worn.
4. Remove the cover.
5. Check or any obvious alterations. Use good judgment as to the sa ety o any alterations.
6. Check inside the unit or any obvious unsa e conditions, such as metal ilings, contamination, water or
other liquids, or signs o ire or smoke damage.
7. Check or worn, rayed, or pinched cables.
Chapter 1.Important sa ety in ormation 3

8. Check that the power-supply cover asteners (screws or rivets) have not been removed or tampered
with.
Handling electro tatic di charge- en itive device
Any computer part containing transistors or integrated circuits (ICs) should be considered sensitive to
electrostatic discharge (ESD). ESD damage can occur when there is a di erence in charge between objects.
Protect against ESD damage by equalizing the charge so that the machine, the part, the work mat, and the
person handling the part are all at the same charge.
Note :
1. Use product-speci ic ESD procedures when they exceed the requirements noted here.
2. Make sure that the ESD protective devices you use have been certi ied (ISO 9000) as ully e ective.
When handling ESD-sensitive parts:
• Keep the parts in protective packages until they are inserted into the product.
• Avoid contact with other people while handling the part.
• Wear a grounded wrist strap against your skin to eliminate static on your body.
• Prevent the part rom touching your clothing. Most clothing is insulative and retains a charge even when
you are wearing a wrist strap.
• Use the black side o a grounded work mat to provide a static- ree work sur ace. The mat is especially
use ul when handling ESD-sensitive devices.
• Select a grounding system, such as those listed below, to provide protection that meets the speci ic
service requirement.
Note: The use o a grounding system is desirable but not required to protect against ESD damage.
– Attach the ESD ground clip to any rame ground, ground braid, or green-wire ground.
– Use an ESD common ground or re erence point when working on a double-insulated or battery-
operated system. You can use coax or connector-outside shells on these systems.
– Use the round ground-prong o the ac plug on ac-operated computers.
Grounding requirement
Electrical grounding o the computer is required or operator sa ety and correct system unction. Proper
grounding o the electrical outlet can be veri ied by a certi ied electrician.
Safety notice (multi-lingual tran lation )
The caution and danger sa ety notices in this section are provided in the ollowing languages:
• English
• Arabic
• Brazilian/Portuguese
• Chinese (simpli ied)
• Chinese (traditional)
• French
• German
• Hebrew
4M90n-1 Hardware Maintenance Manual