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Set Top Box Repaired

By on June 11, 2015
set top box repairing








The complaint of this X.Vision set top box was it can’t boot thus no video and audio from the output port: A/V and HDMI.

set top box repair

I opened the cover and checked on the important voltage test points.

set top box repairs

The output of power supply were good  : 5V , 12 V. So the focus now was on the mainboard. The first voltage test point that I checked was the Flash IC (W25Q32(SO8)) pin 7,8 and it reads only 2.01 volt. It should be 3.3 volt.

Below are the measurements of the output voltages from the SMD voltage regulator ICs: U1, U3 and U4.

set top box repairings

Output of U3 is 5v for mainboard. Output of U4 is 1.8 v for CPU but now it was zero volts. This means the IC have problem and need to replace. I wanted to replace the U4 IC (AB3F1) but I can’t find it in electronic stores so I used a substitute part number SY8009A/SY8009B. You can check out the IC data below:

set top boxrepair

Therefore, I replaced U4 with SY8009B/2A/6PIN , and VCC output of W25Q32(SO8) became: 3.3 v and the set top box came back to life again.









This article was contributed by M.Reza from Iran.

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  1. farhad rigi

    June 11, 2015 at 12:32 pm

    m.reza tanks.

  2. Albert

    June 11, 2015 at 1:30 pm

    Thank you M.Reza. Short but also very interesting repair. These power ic's are always good to know for equivalent replacements. Especially when you do not have Service manual available like in comparable devices such as Dreambox Sat recievers,etc.

  3. Luciano

    June 11, 2015 at 2:13 pm

    Hi M. Reza,
    this is a very educative and informative repair article. Keep it up!

  4. Humberto

    June 11, 2015 at 8:07 pm

    Good repair Mr. Reza, congratulations and keep up.

  5. Waleed Rishmawi

    June 12, 2015 at 12:39 am

    thanks for the repair info. keep up the good work

  6. Andre Gopee

    June 12, 2015 at 2:02 am

    Thanks for the article Mr. Reza. Nice job and well done.

  7. Debirt Maynard

    June 12, 2015 at 8:41 am

    Your article addresses an area in which I have a keen interest. A lot of the clone STBs out of China develop the same problem sooner or later. Good work.

  8. Yogesh Panchal

    June 12, 2015 at 2:55 pm

    Good attempt thanks for sharing.

  9. reza

    June 13, 2015 at 1:06 pm

    Hello to all
    I am sorry the U1 is defective.
    I replace U1 and the set top box came back to life again.
    thank u very much.

  10. parminder singh

    June 13, 2015 at 10:42 pm

    ya this is good knowledgeable article
    i also repaired my airtel dth setup box their was problem of detction of
    viewing card.

  11. Anand Palkar

    June 15, 2015 at 12:38 am

    Excellent article and good logic how did you get the substitute that's also important moreover the voltage that has been pulled to zero could be by two reasons one is as you have pointed out that U1 is defective and the other reason is shorted component in the output. Its sometimes a gamble and you are not lucky always thats why i think a leak detector becomes useful.
    Thanks for sharing

  12. amin

    June 15, 2015 at 9:27 pm

    salam m-reza tank you

  13. mmoni Diphera

    June 18, 2015 at 1:43 pm

    i like it ,keep it up

  14. Mo

    July 3, 2015 at 11:05 pm

    Hello Mr.Reza
    I thank you for this post very helpful presentation.

  15. suraj

    October 10, 2015 at 5:00 pm

    Hello Sir, I am facing the problem that my flash IC bootloader is corrupt. The box turns on and then again gets off. Do I need to change the flash? If I change it then how will I provide it the bootloader? If not then what could be the solution to it?

  16. shahid ahmad

    May 8, 2016 at 3:37 am


  17. Addas momin

    September 18, 2016 at 2:07 pm

    Well i have a problem with my smps setoff box which is a channel locked, parental lock, how to reset setoff box i can't reset it in the menu option which is lock itself how to reset? It's 4 digit pin box appear when i open menu or a channel. Plz help

  18. dayanand

    April 29, 2017 at 5:56 pm

    we servicing set top box. due high volts the microcontroller is short .we replace by new mcu. the set top box is but its box number is change. in mcu memory is there in that unique number is store how to delete this number and how to add new number

  19. ashish kanoja

    July 15, 2017 at 9:05 pm

    sir i want to changhong ch-8501M stb for siti cable . circuit diagram and foult finding .

  20. Nitin

    August 29, 2017 at 9:50 pm

    Hatway C9000n dead problem

  21. ashish kanoja

    April 12, 2019 at 2:39 pm

    Gospel GCR L316 set top box Foult finding please........


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