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About Thermistor

By on September 13, 2009


Normally most of the electronic components like capacitors, bridge rectifiers, transistors, IC, diodes, resistors and etc have their own code which is quite easy to read. For example, a 104 capacitor we know that it is a .1 microfarad capacitor, a 1n4007 have the spec of 1000 volt with 1 ampere and so forth. However, for the Thermistor there are so many part numbers and almost all of them have different code which make us as electronic repairer have a hard time trying to locate the part.  Usually what i did was to get a replacement from a junk board and i have plenty of junk boards!

I wish that those Thermistor manufacturers could set a standard code so that it would make our life easier especially for those who are new in this repair field. Beginners might have thought of the component could be a Varistor and a wrong replacement might cause the equipment not to function. For your information, if you did not look at the board location you would think that a Varistor is a Thermistor and a Thermistor is a Varistor!



  1. Papo

    September 21, 2009 at 3:35 pm

    Hello Jestine,
    Currently I have a problem with a Genexxa CTV10 10" color TV. The volume up/down is not functioning. It's permanently loud. The sound IC is AN5265. Volume control pin 4 is permanently on 2.5V. I traced to pin 20 of M34300-012SP (a 42 pin IC). The voltage is permanently 1.8V even when the volume button is pressed continuously.

    What do I do.

  2. admin

    September 23, 2009 at 9:56 pm

    Hi Papo,
    I have not come across such problem before but one of my repair friend told me that a bad eeprom data could cause such problem. Have you replace the sound IC?


  3. azmoeen

    January 19, 2010 at 3:00 pm

    ineed book help me to find addifrent betoween compunt viue.

  4. admin

    January 19, 2010 at 9:04 pm

    Hi Azmoeen,

    I don't understand your question, could you elaborate?


  5. Peter

    October 19, 2010 at 11:36 pm


    Maybe you can help me, I have a CRT monitor that suddenly stopped working and I found that the board is a bit brown where the thermistor is at, so I tested it with a multimeter and the resistance is 20ohm at room temperature, then I heated it a bit and it came down to 5 and then it went back to 18, do you believe it could be bad?

    Also I hear a cricket-like sound every half second when the monitor is connected so I believe it could be a bad capacitor instead but I can't visually find any bulging. I don't want to remove them unless necessary.

  6. admin

    October 20, 2010 at 4:47 am

    HI Peter,

    It should be good. The best test is power on and test the ac supply to the bridge rectifier to see if the ac supply change when the monitor stop working.

    As for the sound, it can comes from any components. Try power it on and use the handle of screw driver and gently tap on the transformer and flyback to see if the sound will go away or not.


  7. Peter

    October 21, 2010 at 11:39 am

    I finally found the sound is coming from the switching transformer, then I tested the DC voltage and I got 0 so I guess I need a new switching transformer, the fuse, bridge rectifier and other componets seem to be ok.

    Thank you.

  8. admin

    October 21, 2010 at 7:16 pm

    HI Peter,

    Sometimes secondary side components shorted also could cause the transformer to have sound. I suggest that you check the secondary section too.



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