Lenovo ThinkPad W541 (English) Hardware Maintenance Manual - ThinkPad T540p, W - Page 45

No-beep symptoms, LCD-related symptoms, Intermittent problems, Important, Notes, atleast10times

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No-beep symptoms Table 5. No-beep symptoms Symptom or error No beep, power-on indicator on, LCD blank, and no POST. No beep, power-on indicator on, and LCD blank during POST. The power-on password prompt appears. The hard-disk password prompt appears. FRU or action, in sequence 1. Ensure that every connector is connected tightly and correctly. 2. Reseat memory module. 3. Replace the system board. 1. Reseat memory module. 2. Replace the system board. A power-on password or a supervisor password is set. Type the password and press Enter. A hard disk password is set. Type the password and press Enter. LCD-related symptoms Important: The TFT LCD for the notebook computer contains many thin-film transistors (TFTs). The presence of a small number of dots that are missing, discolored, or always lighted is characteristic of TFT LCD technology, but excessive pixel problems can cause viewing concerns.If the LCD you are servicing has two or less visible defective pixels, it should not be considered faulty. However, if the LCD has three or more visible defective pixels, it will be deemed as defective by Lenovo and it should be replaced. Notes: • This policy applies to all ThinkPad notebooks purchased on 1 January, 2008 or later. • Lenovo will not provide warranty replacement if the LCD is within specifications because we cannot guarantee that any replacement LCD will have zero pixel defects. • One pixel consists of R, G, B sub-pixels. Table 6. LCD-related symptoms Symptom or error No beep, power-on indicator on, and a blank LCD during POST. • LCD backlight not working. • LCD too dark. • LCD brightness cannot be adjusted. • LCD contrast cannot be adjusted. • LCD screen unreadable. • Characters missing pixels. • Screen abnormal. • Wrong color displayed. Horizontal or vertical lines displayed on LCD. FRU or action, in sequence Replace the system board. 1. Reseat the LCD connectors. 2. Replace the LCD assembly. 3. Replace the system board. 1. See important note for "LCD-related symptoms." 2. Reseat all LCD connectors. 3. Replace the LCD assembly. 4. Replace the system board. Replace the LCD assembly. Intermittent problems Intermittent system hang problems can be due to a variety of causes that have nothing to do with a hardware defect, such as cosmic radiation, electrostatic discharge, or software errors. FRU replacement should be considered only when a problem recurs. When analyzing an intermittent problem, do the following: 1. Run the diagnostic test for the system board in loop mode at least 10 times. Chapter 4. Related service information 39

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No-beep symptoms
Table 5. No-beep symptoms
Symptom or error
FRU or action, in sequence
No beep, power-on indicator on, LCD blank, and no
POST.
1.
Ensurethateveryconnectorisconnectedtightly
and correctly
.
2. Reseat memory module.
3. Replace the system board.
Nobeep,power-onindicatoron,andLCDblankduring
POST.
1.
Reseat memory module
.
2. Replace the system board.
Thepower-onpasswordpromptappears.
Apower-onpasswordorasupervisorpasswordisset.
Typethepasswordandpress
Enter
.
Thehard-diskpasswordpromptappears.
A hard disk password is set. Type the password and
press
Enter
.
LCD-related symptoms
Important:
The TFT LCD for the notebook computer contains many thin-film transistors (TFTs). The
presenceofasmallnumberofdotsthataremissing,discolored,oralwayslightedischaracteristicofTFT
LCDtechnology,butexcessivepixelproblemscancauseviewingconcerns.IftheLCDyouareservicinghas
twoorlessvisibledefectivepixels,itshouldnotbeconsideredfaulty.However,iftheLCDhasthreeormore
visibledefectivepixels,itwillbedeemedasdefectivebyLenovoanditshouldbereplaced.
Notes:
•ThispolicyappliestoallThinkPadnotebookspurchasedon1January,2008orlater.
•LenovowillnotprovidewarrantyreplacementiftheLCDiswithinspecificationsbecausewecannot
guaranteethatanyreplacementLCDwillhavezeropixeldefects.
• One pixel consists of R, G, B sub-pixels.
Table 6. LCD-related symptoms
Symptom or error
FRU or action, in sequence
Nobeep,power-onindicatoron,andablankLCDduring
POST.
Replace the system board.
• LCD backlight not working.
• LCD too dark.
• LCD brightness cannot be adjusted.
• LCD contrast cannot be adjusted.
1.
Reseat the LCD connectors
.
2. Replace the LCD assembly.
3. Replace the system board.
• LCD screen unreadable.
• Characters missing pixels.
• Screen abnormal.
• Wrong color displayed.
1.
Seeimportantnotefor“LCD-relatedsymptoms.”
2. Reseat all LCD connectors.
3. Replace the LCD assembly.
4. Replace the system board.
HorizontalorverticallinesdisplayedonLCD.
Replace the LCD assembly
.
Intermittent problems
Intermittentsystemhangproblemscanbeduetoavarietyofcausesthathavenothingtodowithahardware
defect,suchascosmicradiation,electrostaticdischarge,orsoftwareerrors.FRUreplacementshouldbe
consideredonlywhenaproblemrecurs.
Whenanalyzinganintermittentproblem,dothefollowing:
1.Runthediagnostictestforthesystemboardinloopmode
atleast10times
.
Chapter 4
.
Related service information
39