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Sparking In The CRT Tube Neck

By on January 24, 2010

picture tube gun

If you come across sparking (blue arc) internally in the CRT tube neck, there could be two causes. It could be the high voltage generated too high by the flyback transformer (due to a higher than normal B+ voltage) or the picture tube itself have problem. A leak (usually a mild crack at the neck of the picture tube) would cause the air to rush in. For your information, inside picture tube is a vacuum and assuming you accidentally break the tube neck you will hear a sound of air going in and NOT gases that are coming out.

First make sure that the anode voltage is within the spec of about 24 Kvdc. Test the anode voltage with a high voltage probe.  If the anode voltage tested good then suspect abad tube. If the anode voltage is higher than normal then check the B+ voltage or even the internal capacitor. In some Monitor design the feedback produced by the internal capacitor will send to the B+ circuitry and if this internal capacitor have problem, the B+ voltage will shoot up thus causing the anode voltage to increase. Again in some Monitor design, the high voltage shutdown circuit is not sensitive enough and will not shutdown the high voltage and this will cause arcing in the neck of the picture tube.

By the way, i did not catch any big fish, only small fishes but I’m equally happy be able to fellowship with some of my buddies.



  1. nowdaygood

    January 24, 2010 at 11:06 am


  2. Dat Tran

    October 8, 2010 at 10:41 am

    Hi Sir/Madam

    My need CRT Part naumber M36EDR320X304/6F01 / M36EDR323X130/6CF1R /
    M36LBL803X12 / M36lbl803x01/M36EDR320X130 And M36AES83X46
    How Much one each Thank you

  3. admin

    October 8, 2010 at 9:07 pm

    HI Dat,

    Sorry i do not sell spare parts and picture tube.


  4. silverthana

    May 10, 2011 at 1:17 am

    I have faced the same problem at samsung tv 29inch with crt make by samsung.
    have laser light(star war gun) and krik krik sound inside the tunnel tube.I guest the crt already shorted and damage cannot be repair.Do you guest the same condition.few years ago I have same problem with Sharp TV using samsung result the set I have given free to scrap shop.

  5. admin

    May 10, 2011 at 3:31 am

    HI Silverthana,

    Yes i guess the tube already have problem.


    • vikas

      July 8, 2015 at 2:54 pm

      Yes sir same problem with me,and picture clear but spark inside ...

  6. thoibi

    October 16, 2014 at 1:04 pm

    I have a problem in my crt 29 inch LG tv,the proble is i hear some unnatural sound like kirk kirk inside the tunnel tube and saw laser light but i can see the picture very clearly on the screen, what may be the cause ?

    • Jestine Yong

      October 18, 2014 at 9:16 am

      Do you mean the TV is good except those sound?


  7. dalganjan kurre

    April 2, 2016 at 8:55 pm

    my sansui crt tv screen is sparking what could be the problem.

    • Jestine Yong

      April 4, 2016 at 8:00 am

      Check these links: and


  8. willesstar syiem

    July 26, 2016 at 2:11 pm

    my videocon 21' inch crt tv have hissing sound inside the tube and a huge blue spark in the anode, after i changed EHT, i have already cleaned and apply some tube paste on it, but the sound (shiw shiw)inside the tube is still there, what will be the problem?

    • Jestine Yong

      July 27, 2016 at 7:29 am

      Hi Willesstar,

      The tube have problem and you need to replace it.


  9. Rajib Singh

    July 26, 2016 at 2:23 pm

    I have a china c.r.t t.v , it was sparking problem but t.v was okay , sparking from high voltage wire , but yesterday when i going to start t.v , it sparks as regular do and suddenly gonna dead , after that I have changed 2 times t.v fuse and 1 time h.o.t , but still dead and fuse burns again and again , please help me . I have repaired 6 to 7 times in last 1 years . It is almost 2 years old t.v set

    • Jestine Yong

      July 28, 2016 at 5:25 pm

      Hi Rajib,
      If it sparks from the flyback then you need to change the flyback because the spark could kill the HOT.


  10. Sagar

    September 20, 2016 at 4:42 pm

    Sparking on TV tube where plug connection coming from flyback transformer n how to connect new flyback transformer

  11. randy

    October 12, 2016 at 11:33 am

    my samsung crt tv 21" sparking in flyback cap the high voltage comes out.I replace fbt but Idoesnt change.what other possible trouble

    • Jestine Yong

      October 12, 2016 at 1:14 pm

      Hi Randy,

      It could be the tube problem or the B+ voltage too high. Make sure the anode cap area in pc tube is clean.


  12. Jason Kim

    December 1, 2016 at 11:16 am

    Hi Jestine,

    I have the same issue, I hear hissing sound on the anode cap are but there is no arc, and I can smell something also. May I know the cause why the B+ becomes too high? Thanks in advanced.

    • Jestine Yong

      December 5, 2016 at 9:02 am

      Hi Jason,
      Try clean the anode cap and flyback area. The B+ voltage too high due to the power supply. If B+ is high then other voltages from the power supply normally will go high unless the B+ is using different circuit such as buck or boost circuit.


  13. james

    December 9, 2016 at 10:11 am

    sir im from philppines my tv is when you on the button it start spark inside and there is a bad smelling smoke what is the problem

    • Jestine Yong

      December 9, 2016 at 3:44 pm

      Hi James,

      Usually the spark is from the flyback or CRT TUBE. You have to remove the cover and investigate. If you have no experience in electronics repair I suggest that you send to a repairer to check for you.


  14. himanshu

    January 6, 2017 at 7:42 pm

    if spark over final anod ..then clean it and use gusekit maker (automativ use ) on the conecting surface your problem wil be solve.

  15. manipur

    February 18, 2017 at 3:58 pm

    is problem or not ??? i cant see carbon painting tube near flyback cap it seems like erase ... help me


    May 2, 2018 at 10:22 am

    sir jestine,mine is crt tv 14inch sony hissing sound coming from area of flyback node cap,pic and sound is ok

    • Jestine Yong

      May 3, 2018 at 12:30 pm

      Hi Engineer Junior,

      Probably is the fault of the flyback if no other components that is bad in the surrounding area.



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