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Stand By Red Light In LCD TV Repaired

By on June 11, 2020

how to fix sanyo lcd tv problem

This Sanyo LCD TV 24″ came in for repair with the complaint of red light problem. Red light means stand by power fault. It also mean no display until you have sort the problem out. Stand by problem usually can be caused  by bad power supply or the main board. If the power supply is supplying good 5 volt DC then the fault is in the main board.

If the power supply have only few volts ( 2 to 3 volt) this could mean the power DC rail filter capacitor could have fault. So in this case, I got 5 volt DC output from the power supply and I measured it at the output connector pin 4 and 5 (see the photo below):

3.3 volt lcd tv connector

The DC 5 volt is going to the two boards (tuner and main board):

lcd tv board  sanyo for repair

Tuner and Main board

The easiest point to check in the mainboard is the SMD voltage regulator IC. Look at the part number and see what will be the output voltage.

In my case, it was the 3.3 volt voltage regulator IC. It has the input 5 volt but does not have 3.3 volt. The voltage that I got was lowered than 3.3 volt!

3.3 volt voltage regulator ic

Since the output voltage was lowered than 3.3 volt this mean this particular IC could have problem. You also need to know that sometimes the lowered voltage could be caused by a leaky component along the 3.3 volt line.

new 3.3 volt voltage regulator ic replacement

To confirm it, I simply replaced the IC and do a check on the output voltage. It was 3.3 volt! So this means there is nothing leaky in the 3.3 volt rail.

3.3 voltage regulator replaced in lcd tv

I lifted the LCD panel and saw the display. I put back everything  and powered it on. The next photo was what I saw and happy with the result.

how to repair lcd tv sanyo

how to fix and repair lcd tv

Conclusion- If after fixing the new 3.3 volt voltage regulator IC and the output voltage is still low then I need to check on the components that is connected to the 3.3 volt power rail. It could be a shorted cap, leaky IC and etc. If  you want to know  more about  LCD TV Mainboard power faults  you can check out on Damon’s ebook HERE.


This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.

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  1. Bobby Y

    June 11, 2020 at 8:42 pm

    This is very helpful.
    Thank you


  2. Parasuraman S

    June 11, 2020 at 8:55 pm

    Another professional straightforward job! Well done!

    • Kirti Navrang

      June 13, 2020 at 10:49 am

      Very good

  3. Albert van Bemmelen

    June 11, 2020 at 10:41 pm

    I guess that sometimes these regulators just quit working. Or maybe it is because of an increasing power consumption on the 3.3V output connection that shortens its life? (possibly if it was designed with too critical tolerance levels).

  4. Andrew F. Ali

    June 12, 2020 at 12:48 am

    I always appreciate how simple you explain each step. Thanks. Good job.

  5. Ivan

    June 12, 2020 at 2:55 am

    thanks for the lecture

  6. Patrick Ribbsaeter

    June 12, 2020 at 7:53 am

    very nice... thank you

  7. Humberto

    June 12, 2020 at 10:50 am

    Good job, Suranga

    • Prabu

      June 16, 2020 at 1:10 am

      Good explanation

  8. Daniel Vera

    June 15, 2020 at 5:05 am

    Tienes canal YouTube?
    Do you have a YouTube channel?

  9. Akbar

    June 26, 2020 at 3:31 pm

    again a nice job thanks fr sharing

    • ivan

      August 19, 2020 at 10:35 pm

      What if all the regulators output stable voltage and also stb voltage from psu is stable? which component should i suspect next

  10. Issah Shitanda

    November 30, 2020 at 9:00 pm

    Good job bro.

  11. DOĞAN

    December 17, 2020 at 1:24 am

    You're great, master. Greetings from Turkey...


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