fault finding for laptop by Mr tapan kumar

1. LAPTOP REPARING TIPS
By Mr Tapan Kumar Khilar

2. MAJOR PARTS OF LAPTOP
LCD Casing
Internal (unseen) Required Parts
Inverter Board
LCD Cable
Hinges and/or Brackets
External (visible) Required Parts
LCD Screen
Thumb Knob and Latch
Display Bezel
LCD Casing
Internal (unseen) Optional Parts
Wireless Antenna
Microphone
External (visible) Optional Parts
Web Cam

3. Bottom Casing
Internal (unseen) Required Parts
CPU
Memory (RAM)
Video Card
Audio Board
Hard Drive
Motherboard
Power Board
LED Board
Cable Clips
Heat Sinks
CMOS Battery
External (visible) Required Parts
Keyboard
Touch Mouse Pad
Cooling Fans
Battery
Palm Rest
DC Power Jack
Cover Doors

4. Internal (unseen) Optional Parts
Bluetooth Card
Modem
NIC
Wireless Card
External (visible) Optional Parts
Optical Drive (CD/DVD/BluRay)
Memory Card Reader
PCMCIA slot
Speakers
Fingerprint Reader Board
USB Board
A/V Port Board

5. SYSTEM BOARD or MOTHERBOARD
The system board is the main logic board in any
laptop. All internal components are connected to the
system board. This is one of the most expensive
parts in a laptop.

7. RAM
More memory you have installed – better the performance
of the laptop. The memory
is a user replaceable part.

8. HARD DRIVE
The hard drive is the main storage of information in a laptop.
All system files, personal files are stored inside the hard
drive. Faster hard drive you have installed – faster data
access you get. You can upgrade the hard drive yourself.

9. PROCESSOR / CPU
The processor is the brain of your laptop. Faster CPU
means faster data processing.

10. KEYBOARD
The keyboard is the main input device.

11. CD/DVD OPTICAL DRIVE
The CD/DVD drive allows you to read/write data
from/to a CD or DVD disc.

12. COOLING FAN
The cooling fan is a part of the cooling module in a
laptop. The fan helps to cool down the processor when
the laptop is turned on.

13. VIDEO CARD / GRAPHICS CARD
In most modern laptops the video card is integrated into
the system board. If the video card fails you have to
replace the whole motherboard. In some laptops the
video card is a discrete module and can be removed or
replaced separately from the motherboard.

14. AUDIO BOARD / SOUND BOARD
In most laptops the audio board is a part of the
motherboard. If that’s the case, all audio board
input/output components such as volume control,
microphone jack and headphone jack are soldered
directory to the motherboard.

15. WIRELESS NETWORK CARD
The internal wireless card helps you to connect to the
Internet without running a cable.

16. CMOS BATTERY or RTC BATTERY
The CMOS battery provides power to the CMOS chip
when the laptop is turned off or disconnected form
the wall outlet.

17. LCD SCREEN
The LCD screen is one of the most expensive parts in a laptop
computer. The LCD screen mounts inside the display panel.
If you accidentally cracked the screen, it has to be replaced.
You cannot repair a cracked screen.

18. SCREEN INVERTER BOARD or FL INVERTER
The inverter board is a power supply for the backlight lamp
inside the LCD screen. When inverter fails, the LCD screen
goes very very dark and you barely can see any image on the
screen. In most laptops the inverter board is mounted inside
the display panel below the LCD screen.

19. SCREEN BACKLIGHT LAMP or CCFL TUBE
The backlight lamp is the main source of light in the LCD
screen. The backlight lamp is mounted inside the screen. When
the backlight lamp fails, you have to replace the whole LCD
screen. It’s possible to replace just the lamp inside the screen
but it’s very hard and has to be performed by an experienced
technician.

20. SCREEN CABLE or VIDEO CABLE
The video cable connects the Laptop screen to
motherboard. The video cable carries data signal for
the LCD screen and power for the inverter board.

21. WEB CAMERA
Many modern laptops come with a web camera built into the
display panel. The web camera is not a part of the LCD screen.
The web cameras is located on a separate board and can be
replaced separately from the LCD.

22. DISPLAY HINGES or SCREEN HINGES
The display hinges connect two main parts of any
laptop – the display panel and base assembly.

23. AC/DC POWER ADAPTER
The AC/DC power adapter converts high voltage AC power
from the mains to low voltage DC power required by the
laptop.

24. MAIN BATTERY
The battery is a secondary source of power for a laptop. The
battery gets charged while the laptop is plugged into the mains
and keeps the laptop running when it’s unplugged from the
mains.

25. ASSEMBLING LAPTOP / CONNECTIVITY
OF LAPTOP

27. 1. Loose connection between the video cable and the LCD screen.
2. Defective LCD screen.
3. Defective motherboard (I assume the graphics card is integrated into the
motherboard).
Use the laptop with an external monitor
Laptop screen may turn white because of poor connection
between the video cable and the LCD screen.

28. Situation - 1
The laptop appears to be dead. You plug the AC adapter but the LEDs
(power light, hard drive light, battery charge light, etc…) do not light up
and the laptop will not react at all if you press on the power button.
Laptop does not start
First of all in this situation check the AC adapter. You can test
the output voltage with a voltmeter.
If you know that the AC adapter is working properly and it
outputs correct voltage but the laptop is still dead, most likely
you have a power issue on the motherboard

29. Situation 2.
When you plug the AC adapter the power LED and the battery
charge LED light up. When you press on the power button the
laptop powers up but will not start. There is no video on LCD or
external monitor.
Make sure the output voltage of AC adapter is correct.
Unplug the AC adapter, remove the battery and wait for 1 / 2 minutes.
After that plug the AC adapter and try starting the laptop again.
Try reseating the memory module, just remove it from the slot on the
motherboard and install it back. Try installing the memory module into the
other slot (if it’s available). If you have two memory modules installed, try
removing them one by one and start the laptop just with one memory
module installed.

30. Situation 3.
When you press on the power button, the laptop makes a
series or short and long beeps and will not start up. There is
no video on the screen.
Solution:-
Try installing a known good memory module. Most likely you are getting a
beep error because of a faulty memory.
Situation 4.
You start the laptop. It sounds like the laptop is booting normally (hard
drive LED is flashing) but there is no video on the screen
In this situation test the laptop with an external monitor. If the external screen
works fine but there is no video on the laptop LCD, most likely there is a problem
inside the laptop display assembly.

31. Situation 5.
You start the laptop and it starts making repetitive clicking noise or grinding
noise.
Most likely you hear this noise because of a faulty hard drive. You can remove the
hard drive and start the laptop without it. If the noise is gone, the hard drive is
your problem. Replace it.
Situation 6.
The laptop boots into Windows and works for a while, but after that it
shuts down by itself without any reason or warning. You restart the laptop
but the same problem appears again
Most likely it’s a heat related issue. Listen for the cooling fan, make sure it works.
Also this problem might appear because of a faulty memory module.

33. Situation 7
The laptop starts normally but video on the screen has lines, some strange
characters or other defects
It could indicate a problem with the laptop LCD screen, video cable, graphics card
or motherboard.

34. Removing and replacing keyboard
If your keyboard is missing a key, it’s not necessary to replace the whole
keyboard. You can fix a single key without replacing a keyboard.
Warning!
– if your laptop is still covered by the manufacturer’s warranty, do not open
the case or you can loose the warranty.
– always remove the battery and unplug the AC adapter before you open
the laptop case.
– if you damage the keyboard connector on the motherboard you’ll have to
replace the whole motherboard.
– proceed on your own risk.

35. Carefully remove the cap from any other working key so
the key retainer stays connected to the keyboard.
Take a closer look at the key retainer, it’s connected to
the keyboard at four different points.
Assemble the disconnected retainer the same way as one
on the keyboard and put it back in place.
Put the key cap on the retainer and snap the cap back in
place.

37. LAPTOP IS OUT OF NETWORK
Check network driver is installed correctly
Check network cable is plugged tightly
Check your local area network is not disable
Check NIC by ping command (127.0.0.1)
IF BOTH ARE CORRECT
Check your IP address i.e laptop network should be in your local
area network
IF IP SECTION IS CORRECT
Give a ping command to your default gateway and then DNS
server address

38. IF WI-FI IS NOT WORKING
Check wifi driver is installed correctly
Check wifi is not disable
Ensure wifi password enter correctly ( if wifi is protected)
Check IP address
Ping to gateway ( if pinging)
Ping to DNS server

39. IF INTERNAL SPEAKER IS NOT WORKING
Ensure sound driver is installed correctly
Ensure speaker is not muted
IF BOTH ARE CORRECT
Internal sound card may be faulty
IF INTERNET IS NOT WORKING
Ensure your Local area network and WIFI is working properly
If both are working
Check your browser setting , your browser may be corrupt

41. CHECK POWER CABLE IS OK BY MULTIMETER OR TESTOR ( IF OK)
CHECK SMPS IS WORKING PROPERLY
CHECK CONNECTIVITY OF INTERNAL COMPNENTS
REMOVE RAM AND CLEAN THEN REINSERTED PROPERLY
CHECK VGA CABLE IS FIXED PROPERLY
CHECK POWER IS ON TURNED ON THE MONITOR
REMOVE ALL THE RAM AND CLEAN THEN INSERT ONE BY ONE RAM
INTO THE SLOT
SOMEIMES RESOLUTION IS THE CAUSE FOR NOT DISPLAY DUE TO HIGH
RESOLUTION

42. COMPUTER IS OUT OF NETWORK
Check network driver is installed correctly
Check network cable is plugged tightly
Check your local area network is not disable
Check NIC by ping command (127.0.0.1)
IF BOTH ARE CORRECT
Check your IP address i.e computer network should be in your
local area network
IF IP SECTION IS CORRECT
Give a ping command to your default gateway and then DNS
server address

43. How to recognize the beep errors
Very short beep
This problem is linked to your motherboard. It can also mean that
you are facing a problem with your system memory (BIOS AWARD)
Long beep followed by three sequential short beeps.
This issue is linked to your graphics card configurations.
Short beep followed by three sequential long beeps
You are facing a system memory problem.
Beep, pause, beep, pause, two sequential beeps
This error is linked to your CPU.
Three beeps, pause, three beeps, pause, four beeps
You have an issue with the video memory.

44. One long beep and nine short
Problem with the ROM (Bios AWARD).
Three beeps, pause, four beeps, pause, beep
This is linked to an error with your graphics card.
Four beeps, pause, three beeps, pause, beep
You have a system memory problem.
Five short beeps
You are facing a problem with your CPU.
Long constant beeps
It's a system memory problem.
Tips
If your PC beeps after the OS has been launched, it may be due to the
fact that your CPU is overheating and that could be a serious matter.

45. Beep Code: Description of Problem:
No Beeps Short, No power, Bad CPU/MB, Loose Peripherals
One Beep Everything is normal and Computer POSTed fine
Two Beeps POST/CMOS Error
One Long Beep, One Short Beep Motherboard Problem
One Long Beep, Two Short Beeps Video Problem
One Long Beep, Three Short Beeps Video Problem
Three Long Beeps Keyboard Error
Repeated Long Beeps Memory Error
Continuous Hi-Lo Beeps CPU Overheating

46. NO SOUND FROM SPEAKERS
Open Start, enter Device Manager, and select it from the list of results. Under Sound,
video and game controllers, select your sound card, open it, select the Driver tab and
select Update Driver. If Windows doesn’t find a new driver, look for one on the device
manufacturer’s website and follow their instructions.
If those steps didn’t work, try uninstalling your audio driver: open Device Manager, right-
click (or tap and hold) the audio driver, and select Uninstall. Restart your device and
Windows will attempt to reinstall the driver.
If that didn’t work, try using the generic audio driver that comes with Windows. Here’s
how: in Device Manager,right-click (or tap and hold) your audio driver > Update driver
software… > Browse my computer for driver software > Let me pick from a list of device
drivers on my computer, select High Definition Audio Device,select Next, then follow
the instructions to install it.
2. Check Power and Cables
3. Re-seat Audio Cables
4. Check Volume Levels
5. Check Device Drivers
6. Run Diagnostics
Run DirectX Diagnostics

47. Computer powers up but nothing on screen
1. check the RAM is seated
2. Try any other RAM
3. still the same problem check the video or graphics card , if any
4. if no graphics card and problem stiil changing it clear your CMOS by removing
battery
6. still problem , check the processor heat sink
7. still problem then suggesting checking motherboard and processor
2. make sure your monitor is working properly.
3. verify that the power supply voltage switch is set correctly. If the input voltage for
the power supplyis not correct (based on your country) then your computer may
not turn on completely.
4. Reseat the CPU only if you suspect that it might have come loose or might not have
been installed properly.
5. Start your computer with essential hardware only. The purpose here is to remove
as much hardware as possible while still maintaining your PC's ability to power on.

48. The LCD monitor has shadows, lines, or ghostly, blurry, fuzzy, hazy,
tinted, or faded images or colors.
1. Ensure the monitor cables are correctly connected.
2. Remove any monitor extension cables.
3. If the monitor accepts more than one input source, press the INPUT button on the
monitor to cycle through input modes.
4. If using the AC adapter, disconnect the AC adapter from any power strip or
surge protector and connect it directly into a wall outlet.NOTE: If this eliminates the
display issues then the problem lies with the power strip or surge protector. Contact the
manufacturer of the power strip or surge protector device for further assistance.
5. Remove any magnetic devices, electrical devices, speakers, lamps or fans from
the vicinity of the computer.
Remove any devices connected to the same wall outlet or electrical circuit as the monitor.
6. If the issue is that the fonts and text are distorted or blocky, it may be necessary
to adjust the pitch and phase settings of the monitor.
7. Reset the LCD to the factory default settings.
8. Perform a self test.
9. Wiggle the cable where it connects to the LCD panel.
NOTES:The LCD has two possible connection methods, using either the HD-15 cable or
the DVI-D cable.
Ensure the input selected corresponds to the input port being used.
If wiggling the cable causes the problem to go away and then come back, the cable
may be damaged or have an electrical short, or the connector on the LCD is faulty.

49. 10. If a video pass-through card is being used, bypass the video pass-through
connection and connect the monitor directly to the video card.
NOTE: If this eliminates the display issues then the problem lies with the video pass-
through device. Contact the manufacturer of the video pass-through device for further
assistance.
11. Move the computer and monitor to a different room.
NOTE: If this eliminates the display issues then an EMI or AC voltage problem exists in
the original room. A line conditioner may help, but is not guaranteed to resolve voltage
problems.
12. Connect the monitor to a different computer.
NOTE: If this eliminates the display issues then a software or video card problem exists
on the original computer.
13. Replace the monitor cable being used with either a different cable of the
same type, or a cable of another type (HD-15/DVI-D).

50. REASONS WHY PCS CRASH
Fatal error: the system has become unstable or is busy," it says. "Enter to return to
Windows or press Control-Alt-Delete to restart your computer. If you do this you will lose
any unsaved information in all open applications."
You have just been struck by the Blue Screen of Death. Anyone who uses Microsoft
Windows will be familiar with this.
1.) Hardware conflict
The number one reason why Windows crashes is hardware conflict. Each hardware device
communicates to other devices through an interrupt request channel (IRQ). These are
supposed to be unique for each device.
For example, a printer usually connects internally on IRQ 7. The keyboard usually uses IRQ
1 and the floppy disk drive IRQ 6. Each device will try to hog a single IRQ for itself.
If there are a lot of devices, or if they are not installed properly, two of them may end up
sharing the same IRQ number. When the user tries to use both devices at the same time, a
crash can happen.
Start-Settings-Control Panel-System-Device Manager.

51. 2.) Bad Ram
Ram (random-access memory) problems might bring on the blue screen of death
with a message saying Fatal Exception Error. A fatal error indicates a serious
hardware problem. Sometimes it may mean a part is damaged and will need
replacing.
3.) BIOS settings :
Once inside the BIOS, great care should be taken. It is a good idea to write down
on a piece of paper all the settings that appear on the screen. That way, if you
change something and the computer becomes more unstable, you will know what
settings to revert to.
A common BIOS error concerns the CAS latency. This refers to the Ram. Older EDO
(extended data out) Ram has a CAS latency of 3. Newer SDRam has a CAS latency
of 2. Setting the wrong figure can cause the Ram to lock up and freeze the
computer's display.
4.) Hard disk drives :
After a few weeks, the information on a hard disk drive starts to become
piecemeal or fragmented. It is a good idea to defragment the hard disk every
week or so, to prevent the disk from causing a screen freeze.
Go to
Start->Programs->Accessories-> System Tools-> Disk Defragmenter

52. Some lockups and screen freezes caused by hard disk problems can be solved by
reducing the read-ahead optimisation. This can be adjusted by going to
Start->Settings->Control Panel->System Icon-> Performance->File System->Hard Disk
Hard disks will slow down and crash if they are too full. Do some housekeeping on your
hard drive every few months and free some space on it. Open the Windows folder on the
C drive and find the Temporary Internet Files folder. Deleting the contents (not the
folder) can free a lot of space.
Empty the Recycle Bin every week to free more space. Hard disk drives should be
scanned every week for errors or bad sectors. Go to
Start->Programs->Accessories->System Tools->ScanDisk
5) Fatal OE exception errors and VXD errors are often caused by video card problems.
These can often be resolved easily by reducing the resolution of the video display. Go to
Start->Settings->Control Panel->Display->Settings
6.) Viruses :
Often the first sign of a virus infection is instability. Some viruses erase the boot sector of
a hard drive, making it impossible to start. This is why it is a good idea to create a
Windows start-up disk. Go to
Start->Settings->Control Panel->Add/Remove Programs

53. 8.) Software :
A common cause of computer crash is faulty or badly-installed software. Often the
problem can be cured by uninstalling the software and then reinstalling it.
Often a Windows problem can be resolved by entering Safe Mode. This can be done
during start-up. When you see the message "Starting Windows" press F4. This should
take you into Safe Mode.
Safe Mode loads a minimum of drivers. It allows you to find and fix problems that
prevent Windows from loading properly.
Remember to restore all the BIOS settings back to their former settings following
installation.
9.) Overheating :
Central processing units (CPUs) are usually equipped with fans to keep them cool. If the
fan fails or if the CPU gets old it may start to overheat and generate a particular kind of
error called a kernel error. This is a common problem in chips that have been
overclocked to operate at higher speeds than they are supposed to.
CPU problems can often be fixed by disabling the CPU internal cache in the BIOS. This
will make the machine run more slowly, but it should also be more stable.
10.) Power supply problems :
With all the new construction going on around the country the steady supply of
electricity has become disrupted. A power surge or spike can crash a computer as easily
as a power cut.