How to Check Parts of a Mobile Phone for Fault

Santosh Das

Santosh Das is an Engineer, Blogger, Young Entrepreneur and Founder of this Mobile Phone Repairing Website. Santosh possesses vast experience in the field of electronics, telecommunication, Soldering, SMT, ESD Safety, and electronics manufacturing tools, equipment and consumables. Santosh left his job in 2014 and started his own Private Limited Company that deals and supplies PCB Assembly and Rework Tools, Equipment and Consumables. Keep visiting for daily dose of Tips and Tutorials.

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130 Responses

  1. Jose Albogado says:

    Hello sir, my Samsung J7 Pro 2017 fell off from my pants pocket to the floor while I was sitted down on work (it fell with the screen facing upwards). When it hit ground, this weird white squares appeared on the screen, but they instantly disappeared, and the screen didn’t showing anything., except for a strange red/white flash every 10 seconds or so. The phone also vibrated whenever the flashes occured (a short vibration, like the one that happens when you turn on the phone, or put it to charge). At this point, I thought that it was the screen that had broken up, but later, some loud, annoying sounds could be heard from the phone, they were like strong buzzing sounds. They eventually stopped, but came back every now and then, and only stopped completely when the phone finally ran out of battery. Could you please help me with this problem? Could the motherboard have been damaged with the fall, being that the reason of the sounds? Or are they related to the screen?

  2. Hemasurya says:

    How to find out if fault in mobile phone sir

  3. Nayan Jain says:

    Sir,my phone Gionee M5 lite switched off after the battery went 0%.I tried to charge it but ,it didn’t charge and so never turned on.I took it to a local repair shop,he told me that the ‘Power IC ” has got damaged so you’ll need to change the mother board.It’ll cost around Rs.5000!!What should I d0.

  4. Hari says:

    Hi sir, this is harish. My Micromax canvas express 2, is getting heated very much, if I speak continuously for 10 minutes, is there any solution for this?

  5. Ceena says:

    hello sir
    i have dead Huawei p8 mobile phone, when i trying to insert a new battery or old its getting hot like burning in 3 to 10 seconds, same heating with connecting to power supply also. if connect to supply more than 10 seconds there is smell like burning.
    i jave trace the charging section is heating.
    please help sir , which part is faulty

    • Santosh Das says:

      Change the battery connector.

    • Ceena says:

      hello sir
      i also replace the sim connector, but still same issue.
      before charging connector replacing the consuming current (amp) is around 4.5 now around 2.4 , but heating same.
      the charging connector value is around 290. and another side no value. its look like ok.
      same value when i remove connector and check the connector point.

  6. Simon says:

    Good day Sir, how can I fix Nokia C2 displaying contact service

  7. Mohamed akidh says:

    Sir can we solve any mobile phone without fail.?

  8. Davies says:

    Sir please can have your email address so i can send you some Chinese mobile pcb board pictures that i am having problem solving the charging system so that you can show show me how to go about it. Thank you sir i like your site Alot it has made to become the best mobile repairer in my area for now thanks.

  9. Vijay says:

    Sir can you please help me?

    I have samsung cdma sch b339, the mobile is full short.

    I have go to many mobile shop but nobody repair it. So I have decided to repair by myself.

    I have seen many video on YouTube and I have checked that my phone PCB has many shorting capacitor and ragistance, so I have removed those by checking multimeter.

    Now my phone is on but phone is not showing the network tower.

    The phone is accepting the sim on starting like Tata or MTS but after starting the phone, the phone showing searching and after that phone shows that No service……..

    So can you please help me in this problem, I want to repair it…..

  10. Malik berry says:

    but sir ,i need a job i know how to repair

  11. esb 199798 says:

    Nokia c1 01 No screen &keypad light problem after water damage what is solution ?

    • Santosh Das says:

      Disassemble the Phone. Take out the PCB. Clean with IPA or Alcohol and allow to dry. Now Apply FLUX all over the PCB and Apply Heat from some distance using Hot Air Blower. Assemble Back and Check.

  12. mali ali says:

    Sir plz tell me how to remove half shortage…..

  13. amit says:

    How to confirm Mobile phone pcb is ok

  14. farman says:

    Sir ,How To check Handsfree Interface On Nokia 230 pcb

  15. Ritam Roy says:

    My phone touch screen is passing obstructively what to do ?

  16. AMAN KUMAR says:

    Hello sir my android mobile spice 525q is no service bta rha hai. .how to check contiti. .or kitni contiti honi chahiye. .. plc btaye…thanks

  17. UTECH says:

    help me my phone PC just stopped to power on

  18. Mayur says:

    Is it possible to repair fully shorted mobile?

  19. Shankar says:

    Hi sir mujhe mobile repair Kaise karte hai Sabh Mail me dona

  20. Anas says:

    I havr asus zenfone 5 , it has 2150 mh bettry backup , but actully it does’t work only 2 hrs , although it have to works minimum 6 hrs , but thier bettery not working good , although i changed the charger and its Data cable for fast charging and keep maximum time on bettry time duration . But still not stays for long hrs ? What should i do ?

  21. Maas Safraz Naveed Weerabangsa says:

    I just insert the dc power suppley to a samsung galaxy y phone to check but i just forgot to regulate the voltage for 3.7 and at that time the voltage was 11 so waht may be happend to that phone??

  22. vijay says:

    hi sir

  23. Ali says:

    my mobile flash light is not working i change the led bulb but still not working and usb malfunction jab pc say connect karain gay tu message ata hai usb device is not recognize Please tell me is ko kaisay repair karain gay

  24. Ptarul says:

    my nokia 1100 ringer is not working after first step jumpering

  25. Navod Naveendra says:

    Hello Sir

    My mobile phone is draining its battery really soon.
    I replaced the battery but it didnt make much of a difference.
    I also replaced the charger and the cables.

    According to your knowledge, Do you think its Power IC fault?


    • Santosh Das says:

      I don’t think there is any fault in the power IC. Which Phone are you using? See if the battery is Loose or Not. Also remove unwanted Apps and make proper settings for display, wi-fi, Bluetooth etc.

  26. samuel segun sonayon says:

    i want to apply for a certificate training from you sir, if u don’t mine pls.

  27. Milan Das says:

    Hello sir, can call you ?

  28. MUDIT GUPTA says:

    Hi Santosh, I have Samsung Galaxy Note 2 4G model # SGH-I317 (AT&T model from US) which I had been using for past 5 years. Recently phone fell down and stopped responding. When connected with charger over night no progress is shown on the screen other than Samsung Galaxy Note II message. I recently got it check in open market and some said motherboard is not working, charging IC, is not working,etc. No one have this model component and telling to change with Indian component which is 3G. Now I have decided to self repair my phone. Can you guide me and help in this project to idenfy and rectify what part or component on the circuit board need to be replaced so that this carrier locked phone can become reusable. Thanks in advance.

  29. kishan says:

    Bhai mere pas ampear vala DC he mujhe power ic ya cpu karab he kese pta clega….

  30. mtata says:

    sir i find out power on/of is under voltage what to do.

  31. shaikh sayeed says:

    please let me know various problem solutions of a smart phones and the way to check it through multimeter and PCB it will be very kind of you

  32. ganesh says:

    Repair and maltimitar solution reply

  33. shaikh sayeed says:

    thanx a lot sir I am from Maharashtra Latur dist. Udgir. Generally ICS are not available so from where should we buy and LCDs and touch of good quality c/c mic speakers please suggest

  34. shaikh sayeed says:

    fine sir its great to have you may God bless you . Sir how to learn a chip level work where is your institute and how much fees .please respond .

    • Santosh Das says:

      I had my own institute but in West Bengal but it is closed now because I am too busy with my other projects. I don’t know your location but there are many institutes in India providing Chip Level Training. I will suggest you to visit any Samsung Service Center and talk to the person doing chip level repairing and ask for some good institute in your location.

  35. Meelan says:

    Why Nokia Mobiles short using after DC supply machine. After that mobile short only in Nokia tell me pls. Why happen

  36. wasswaz says:

    Thanks soooooooo much i like you!

  37. shajahan says:

    Hi sir How to identify power ic , network ic etc….. Pls tell me sir

  38. Muideen says:

    tecno y4 is decreasing charging, what is the solution

  39. Anakh Ajayan says:

    Really good site

  40. Right says:

    Thanks.. God bless you

  41. Danny says:

    Got a broken phone and it is probably the Power ic. Now, is it possible to take the Power ic from another used phone (same modell) or is it just a bad idea?
    I just want to make it work so I can recover pictures and stuff. So it does not have to be a “good” fix that make the phone work for a long time.

  42. Asif says:

    Sir ,

    i started learning ,mobile phone repairing ,my question is -if customer brings mobile phone which is not working and he may not knowing the exact problem what are all the things we need to check first ,can u pls. explain me with steps .

  43. Krishnamurthyk says:

    V nice brother

  44. Alan says:

    Thank you very much for all your work, Santosh. It really helps.

    Best regards from Brazil.

  45. Hashmat says:

    sms mein “r” Key kaam nahi kar raha hai

    mi a120 Hai plz help me

  46. subho ghosh says:

    Hello sir any death mobile solution please

  47. saqib says:

    How to check whether a mobile is short or not, by both analog and digital multimeter?
    And i got 2 new mobiles like a month ago but when i check them by connecting opposite colour probs to the opposite colour battery connector of them, the needle of analog multimeter moves slightly and go forward and remain there, i have read that if the needle of analog multimeter moves forward even a little, it means that the mobile is faulty and short, but both of them work fine. When i checked them through dc power supply, there was no sign of any short. So plz clarify?

  48. GHAJINI says:


  49. Mohd. Anish says:


  50. MAHER says:

    HI , Thank you for your help ! How do i know the components name ? for an example : if i have galaxy device and if i want to locate the power IC , how do locate that component ? I will waiting for your response . Thanks mate!

  51. karthikeyan says:

    1)In Multimeter which one is good digital or Analogy
    2)If digital meter first Where can i set the for check ohms

    • karthikeyan says:

      1)In Multimeter which one is good digital or Analogy
      2)If digital meter first Where can i set the for check ohms(In multimeter)
      3)If Analog meter first Where can i set the for check ohms(In multimeter)

  52. Gabal Babaji says:

    Hi sir i like ur site very much.body of my cell phone is short .how can i solve this problem.

  53. Gabal Babaji says:

    Hi sir i like ur site very much.but i have a problem,body is short how can i solve this problem

  54. thaunghtay says:

    thank you

  55. .saeed ahmed says:

    Hi sir where r u?

  56. .saeed ahmed says:

    Aoa Sir very nice l like it. Sir plz send me Iphone like 4 4s 5 5s repairing tips to my this Gmail address plz.

  57. yogendra garg says:

    Sir mujhe mobile ki pcb track check kaise krte fuse coil capcatrs digital mieter me kiase check krte hai video chahiye

  58. jitprakash says:

    jai bigyana…

  59. raheem says:

    Sir how to check series current in tablet

  60. YORDANOS says:


  61. rahul says:

    this is a great site,

  62. H.Murugan (mtrendz) says:

    iam not a technician but i visit this this web page. Now i would like to achive a tech..
    very very thanks to all.this articles very usefull…….

  63. amit says:

    Hi samsung v3303 no network problem

  64. Murphy martins says:

    My blackberry turch1 phone is draining fast the battery., pls what’s your advice.?

  65. amit says:

    My nokia c1 is dead on/off swicht voltag 1.43v how to solv

  66. manoj goyal says:

    Can u explain the cool testing,hot testing,parallel track and series track

  67. Fred says:

    Hi, Great site. My Samsung Galaxy Y. switches on but will not get past opening flash and SAMSUNG letters will not go beyond this and when I press off/on with operation key it just goes back to same. Any ideas.

    • Santosh Das says:

      Reset the phone and check. It the problem is not solved by flashing then you may have to reload the software.

  68. kamal says:

    Iphone 3g heating problem near power control ic, check the capacitor as said beeps ?, battery charging connector on logicboard shows 0.7 v on charger plugged , charging port Ok .pls help

  69. amit says:

    How to solv problem

  70. amit says:

    Tellme. How solv the problem

  71. amit says:

    Yes i reset the phone and other sim check but not ok

  72. amit says:

    My nokia mobile problem
    “Invalid sim” how to problem solv

  73. Sayyed Ismail says:

    Hello thanks for detail this is very help full for me

  74. sanjay says:

    Cant hear callers voice in mobile earpiece ,but can hear in loud speaker what is the problem and how to rectify

  75. Suresh says:


    I have Karbon a21 the power on mother board is OK but no display. I changed the display but still it is blank and the display is getting hot at the bottom. What to do now?

    • Santosh Das says:

      There is some short in the phone. The phone Karbon A21 has faults in its design and manufacturing. This is a common problem in all A21. It is better to get rid of the phone and buy a new one. Any money you spend on its repairing will be waste. Never trust Karbon.

  76. A karthik Srinivas says:

    Very useful tutorials… Thanks a lot…

  77. Roki says:

    My mobile phone is turning off. when headphone jack through 9v dc supply.whats the problem.
    thank !!!

  78. raj says:

    is ur collage in jalandhar punjab state thanks

  79. Sushil Kumar says:

    good site.I like.


  80. safwan says:

    hi ray,

    is there any institute of urs where i can learn mobile repairing course


  81. James Imaga says:

    Hi,I’m highly impressed by your tutorials they’re are top class and easy to understand and moreso highly factual I want to say its one of the best I’ve come across on mobile phone repairing tech.Keep the good work up.Please can you send me some tutorials on mobile phone jumper setting I’ll be very grateful.Thanks.U can use my email to reach me.

  82. Eyayu says:

    Very very thanks it is great knowledge in this site .

  83. yemane says:

    you done it best thanks!!

  84. Raju Jat says:

    I love This site

  85. modou says:

    this offers useful guide to beginners in cellphone repair.we would be glad if the info is more comprehensive. thanks a lot

  86. sanyog salve says:

    Hi sir
    I like this site and i learnt so many things .
    and i m very great full to you.

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