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About Fake Transistor

By on July 5, 2010

fake transistor

I have an ERG member who told me that he may have bought a fake transistor. Before that the monitor that he repaired have power and high voltage but after the replacement with the new HOT, now the monitor have no high voltage. Even putting the original HOT back does not make any difference and he found that the new HOT was shorted between the C,E pin. He replaced the HOT because he suspected that the HOT was the cause of the display problem (after knocking on the HOT, the  display with shadow will be gone). So he compared the HOTs and and found some differences especially the top part that was not smooth.  You may see the picture below.

 horizontal output transistor hot

Actually many years back i came across a fake HOT with the number of BU2508DF. It works only on some monitors and not all monitors. I have confirmed it in few different working monitor. When i place the fake transistor on a working Monitor, the monitor start to power blink. Putting back the original HOT, the Monitor came back to life.  If you have came across such situation i would like to hear from you.



  1. Russ

    July 5, 2010 at 2:15 pm

    Could you measure the beta and other specs on the fake with the peak meter and see if there are any differences? I wonder what is going on in side the fake. Is it just another transistor, perhaps a cheaper one with different numbers on it?

  2. admin

    July 6, 2010 at 9:11 am

    HI Russ,
    Since i do not have this transistor with me, guess i have to email him to tell us about the result.


  3. dhrupes

    July 6, 2010 at 3:30 pm

    Laptop Chip Level Repairs Training institute

  4. admin

    July 6, 2010 at 10:00 pm

    HI Dhrupes,

    Sorry we do not have the chip level laptop repair.


  5. admin

    July 7, 2010 at 2:01 am

    HI Russ,

    Yes he told me the hfe for the fake one was 14 and the original one was 23.


  6. Amir Mukhtar

    September 7, 2011 at 3:09 pm

    this above is nice guidance .

    Thanks you
    Amir Mukhtar

  7. Ty

    October 2, 2012 at 2:38 pm

    Counterfeit Electronic Components have been around since the 1960's. If I remember correctly, it stared out whit the STK-xxxx series of hybrid amplifies. Volumes have been written on this subject. Just Google “Counterfeit Electronic Components” and you can spend hours reading about it.

    • Jestine Yong

      October 2, 2012 at 8:32 pm

      Hi Ty,

      Ok thanks for the tip.


  8. Nelson Caballero

    October 15, 2012 at 7:01 am

    Speaking of fake components, we encounters them a lot like fake FBT, HOT, soldering lead, VOM, some are SANWA the ORIG and now the fake is SUNWA.  Before installing parts compare always the letters, paint used, on the body of the original components and also the cost of parts, and the supplier if you have a SHOP or service center.Tips on using / fixing H out. issues is always resolder or check condition of the HDT ckts. and  all H out  used on bigger screens CRTs   are good  for any smaller screens and not vice versa. 

    • Jestine Yong

      October 15, 2012 at 8:57 pm

      Hi Nelson,

      Thanks for the contribution of your knowledge.


  9. corriete

    May 29, 2013 at 4:07 am

    hello repair world. i have STRF6654 WHICH a tv is designed for two legs at front and three at back but this replacements i bought had same numbers. the difference was they had three legs at front and two at back. they could not be used. 1st =front 2 legs back 3 legs
    2nd =front 3 legs back 2 legs

    • Jestine Yong

      May 29, 2013 at 7:33 pm

      HI Corriete,

      Thanks for sharing.



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