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Showing posts from March, 2014

Delayed boot

When I power  on a PC the very first screen of Intel splash logo  stays there on more than 3 minutes then it boots the windows. normally this screen only take few seconds. there is no beep sound hear while booting. I suspect some  hardware problem the PC .so while performing post test the problematic area  cause the lengthy boot. so i did the  following procedure to  pin point the problem switch off the PC  removed hard disk ,CD ROM  and floppy connectors remved all internal USB  and front audio connection switch on the Mother board ,  still problem is there Replace BIOS Battery found it is 2.7 v instead of 3 volt but it is not the culprit. Clean RAM and  and check CPU FAN ,even apply enough heat sink compound to the processor. Remove dust in the mother board with compressed air Inspect any visible burnt or damaged component in motherboard . check capacitor in the motherboard.  power on the PC still the problem is there.wait more than 3 minutes to load windows completely.

Hard disk not spiinning due to SMPS fault

Today one of my costumers PC  I found the following problem A message on  the screen saying that there is no bootable disk. To troubleshoot I did the fallowing procedure 1) open the case 2)check the hard disk. i cannot sense any vibration of hard disk spinning. and hear small moaning from the disk. 3) check voltages in power cable for hard disk , found the 5 V supply is less than normal 4) evidently there is  some problem in 5v regulated supply of  SMPS  power supply. 5) Replace the SMPS  box with new one solved the problem 6) Hard is now spinning.and computer booting without any complaints 

DVD RW Drive Icon missing

After installing a DVD writing software in my system  I lost the DVD RW Drive  icon in"my computer" window. Even after restarting the problem is still there. In device manager the DVD RW Drive  device is marked with an yellow exclamation. It  seems like some driver problem But reinstalling the driver not solve the problem.After some Google search i got the right information here. http://support.microsoft.com/kb/314060/en-us My problem is solved in this way Press the Windows logo key + R to open the Run dialog box. Type regedit in the Run dialog box, then press Enter. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow In the navigation pane, locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318} In the right pane, click UpperFilters . Note You may also see an UpperFilters.bak registry entry. You do not have

Nokia cell phone secrets codes

These Nokia codes will work on most Nokia Mobile Phones *3370# Activate Enhanced Full Rate Codec (EFR) - Your phone uses the best sound quality but talk time is reduced my approx. 5%  #3370# Deactivate Enhanced Full Rate Codec (EFR) OR *3370# *#4720# Activate Half Rate Codec - Your phone uses a lower quality sound but you should gain approx 30% more Talk Time. *#4720# Deactivate Half Rate Codec. *#0000# Displays your phones software version, 1st Line : Software Version, 2nd Line : Software Release Date, 3rd Line : Compression Type. *#9999# Phones software version if *#0000# does not work. *#06# For checking the International Mobile Equipment Identity (IMEI Number). #pw+1234567890+ 1# Provider Lock Status. (use the "*" button to obtain the "p,w"and "+" symbols). #pw+1234567890+ 2# Network Lock Status. (use the "*" button to obtain the "p,w"and "+" symbols). #pw+1234567890+ 3# Country Lock Status. (use the "*&qu

How to read value of a Capacitor ?

Capacitance is the ability to store electrons and is measured in Farads.One Farad is a very large value! So most capacitors used in electronic circuits  are measured in MicroFarads (uF) or even Picofarads (pF). Capacitance = Q / V Where Q is the charge and V is the voltage. Thus the capacitance is the charge divided by voltage. The important parameters of the capacitor are 1. Value -Value is marked on the capacitor directly or in colour codes 2. Tolerance -It indicates how much more or less the actual capacitance of the capacitor 3. Working voltage -It is the maximum voltage a capacitor can withstand before the dielectric breakdown 4. Leakage current .There is always small leakage current in all capacitors. Ideally this should be zero. But no capacitor is perfect without leakage current. Tantalum capacitor is comparatively better with minimum leakage current  Value 1pf (Pico Farad)    = 0.001nf (Nano Farad) 1nf (Nano Farad)   = 0.001μf (Micro Farad) 1μf (Micro farad) =