Wednesday, 6 July 2016

SAMSUNG CRT TV With H-Line

Hi,

Again welcome back .Today's topic is How i solved a Noisy  H-Line in SAMSUNG CRT TV 21"

When customer brought the tv  it was in the condition as in below picture photo.

Generally we came across such kind of many complaints and found the solution which is common  in almost crt TV's.The common route cause is filter capacitors in vertical sections.But here the route cause is not a filter capacitors.It is some what extra ordinary,Later on i will tell you about this fault route cause.Before that let us see the schematic diagram.

Please go through the above vertical circuit diagram.As usual checked all the electrolytic capacitors with my ESR found ok.Then  checked all the voltages as per spec found abnormal at pin 6 measured zero volts.Suspected diode between 2&6 of ic pins faulty.Checked with my fluke meter measured 0.4volts in diode option which is showing ok.Now suspected LA78040 vertical ic faulty which is pulling down to zero @ pin 6. Now  replaced the same and even at this stage no good result fault remain unchanged.Question in mind why voltage is not coming at pin 6 even after checking diode ok & vertical ic replacement.Since Diode is the main component which is carrying voltage to pin 6  Checked the voltage at both anode & cathode pins.But here i am not getting any voltage at cathode pin.  

Directly replaced the diode with new 1N4007. At this stage now i got 17.5Volts DC .Here point to be noted the main culprit is Diode.Even it is OK in bench test but remains faulty.Same is applicable for transistors ,Zenar diodes.So strongly i recommend to our repair technicians not to believe bench tested components bare data.One comes such situations while DE-bugging its better to use voltage testing methods as i did in this model.

Ultimately i got all the required voltages & signals from vertical ic .Nice to see TV is re-life back .Happy to see smile at customer face after delever.This is how i repaired SAMSUNG CRT TV 21.

I will be back with one more intersting topic take care.

 

With best regards 

Basavaraj:BM

basavarajradiotech @gmail. Com

 

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14 comments:

  1. Shuvo19 April 2018 at 19:36

    thanks bro.

    ReplyDelete
  2. juanfer25 April 2018 at 12:36

    ok muy buen aporte

    ReplyDelete
  3. Unknown28 August 2018 at 10:55

    Thnxx

    ReplyDelete
  4. Unknown16 September 2018 at 14:07

    Merci de m'avoir ajouter un plus sur ma connaissance

    ReplyDelete
  5. Unknown16 September 2018 at 14:09

    Merci de m'avoir ajouter un plus sur ma connaissance

    ReplyDelete
  6. Unknown5 April 2019 at 05:58

    Good

    ReplyDelete
  7. Fluke 4430 May 2019 at 20:29

    Thanks

    ReplyDelete
  8. Fluke 4430 May 2019 at 20:29

    Thanks

    ReplyDelete
  9. Unknown15 September 2019 at 02:55

    Thanks for the good INFO..

    ReplyDelete
  10. Unknown10 December 2019 at 07:43

    Thanks. But my problem is different, The screen displays at the middle, straight and solidly wide line at centre horizontally.
    I do all what you have listed above,but still no solution

    ReplyDelete
  11. Unknown22 March 2020 at 20:25

    Thank you for that insight. I learned important troubleshooting technique.

    ReplyDelete
  12. Unknown27 October 2020 at 22:39

    thanks for the good tips.

    ReplyDelete
  13. ANAND KUMAR PRABHAKAR21 November 2020 at 05:29

    SIR IN PHILIPS ULTRA SLIM CRT TV OH LINE HEIGHT ONLY ONE INCHES PICTURE ROLLING SYSTEM IC USED IS TDA 12155PS/N3/3. VERTICAL IC LA78141 IF I PUT NEW IC SAME PROBLEMS. FROM LOT -14V AND +14 VOLTS OK. BUT LOT SECTION INSTEAD OF 180VOLTS ONLY 169VOLTS PRESENT I THINK SYSTEM IC WAS FAULTY COULD ANY ONE KNOWS THIS FAULT

    ReplyDelete
  14. Unknown13 January 2022 at 19:13

    Thank you

    ReplyDelete

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