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Mosquito Killer Racket Repaired For Low Sparking

By on February 16, 2021
d882 transistor

mosquito racket repair

Another racket repaired for above stated problem. When press the button and touch the net it gives very low spark that means no sufficient power is present on the net. Because of low killing power mosquitoes are escape from the net. So I have opened the racket for repair. On physical inspection there is no visible sign of burnt out or broken parts.

how to fix mosquito  racket

As per my previous experience I doubt on Big Capacitor that is 223j2KV.(Most of the time it degrades if racket is in frequently in use for year or two because here we use it for high current spark by shorting two legs of the capacitor).

So on doubt I replaced the Capacitor for further testing. (Always remove the Battery while you are replacing any parts of the PCB and do not forget to discharge the capacitors before working on them).

no high voltage in mosquito racket

how to repair mosquito racket

After replacing the capacitor I have connected the battery and for testing I pushed the button and shorted the net with using screwdriver still the same low spark problem. Now it is time to test all the components on high current oscillator side.

Tested 3 diodes near capacitor marked with RFC4K all are ok. Tested oscillator transformer that is also in normal reading.

transformer reading ohm

Now what remains is Transistor. So I removed the transistor (SD965 NPN) for testing. On testing I did not found any leakage or Shorting but I noticed the reading pattern.

transistor reading pattern

Here reading is bit confusing it should be same. I am not having this transistor with me right now hence I arranged one transistor form my storage where I salveged parts form highly damaged non repaired equipments. so arranged D882 NPN transistor.

Here are some transistors which are commonly used in this type of rackets 2SD965, D882, 8050, BEL188, 2N2222, SL100, BC182, BC338……..

So I have replaced the transistor for the testing. On testing I found loud bang noise of the spark. Tested for few sparks & this is how I revived this racket and now it is time for re assembling……. but suddenly I have one question in my mind about Reading of the Bad transistor so decide to test the reading of this replaced transistor also.

So I removed D882 Transistor from the circuit.

capacitor problem in mosquito racket

D882 transistor bad

And here are the readings of D882 NPN Transistor.

  transistor checking using multimeter

After testing & replacing the transistor I reassembled the racket. Now it is ready for the attack…………

This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.

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Note: You can check his previous repair articles in the link below:

https://jestineyong.com/9w-led-bulb-repaired/

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17 Comments

  1. Parasuraman S

    February 16, 2021 at 1:24 pm

    The mosquito committee would have passed a resolution to 'harm' you! (LOL) So take care!2 (LOL) Many thanks for sharing. Changing the transistor for proper arcing is new to me! Many thanks for sharing!

    Likes(4)Dislikes(0)
    • Yogesh Panchal

      February 16, 2021 at 6:22 pm

      Thank you! sir
      Due to low switching process it does not provide proper power to Transformer.

      Likes(0)Dislikes(0)
      • Ivan

        February 26, 2021 at 6:32 pm

        Wow thanks sir

        Likes(0)Dislikes(0)
  2. Albert van Bemmelen

    February 16, 2021 at 1:24 pm

    Interesting read, good to know. So in this case it wasn't the HV capacitor at fault but the transistor that must have been causing the low sparking problem.

    Likes(3)Dislikes(0)
    • Yogesh Panchal

      February 16, 2021 at 6:25 pm

      Yes Albert.
      In these type of rackets Major Components going bad for Low or No arching are capacitor,transformer & switching Transistor.

      Likes(3)Dislikes(0)
  3. Waleed Rishmawi

    February 16, 2021 at 3:20 pm

    a good device to repair and use. I like the sound of the spark in it. I used to have one but they do not sell these in my area any more sad to say. have a blessed day

    Likes(1)Dislikes(0)
    • Yogesh Panchal

      February 16, 2021 at 6:28 pm

      Waleed,
      I think you do not need it because you already use High Current Transformers with big sparks!(Lol)ha ha ha

      Likes(1)Dislikes(0)
  4. Chris

    February 16, 2021 at 5:24 pm

    Mosquito 0 Yogesh 1

    Likes(1)Dislikes(0)
  5. Yogesh Panchal

    February 16, 2021 at 6:28 pm

    Thanks! Chris

    Likes(1)Dislikes(0)
  6. Gary Gemmell

    February 16, 2021 at 11:19 pm

    Interesting and well laid out i like your photos and explanation it is very well presented!

    Likes(0)Dislikes(0)
    • Yogesh Panchal

      February 22, 2021 at 6:37 pm

      Gary Gemmell,

      Thank you! Sir

      Likes(0)Dislikes(0)
  7. Michael G

    February 17, 2021 at 11:46 am

    Good Job! I have to say your transistor readings for the SD965 NPN were interesting. I would have assumed the transistor was good. I observed similar readings on a TIP 147 used in a subwoofer amplifier, which I still haven't fixed. Perhaps I should replace it. Anyway, thanks and keep the good articles coming!

    Likes(1)Dislikes(0)
    • Yogesh Panchal

      February 22, 2021 at 6:48 pm

      Michael G,
      Sometime Components are behaving very strange On load & out of the circuit.Now a days Rather wasting time in assumption simple way is to replace component and check the equipment if you have same or equivalent in your stock.

      Likes(0)Dislikes(0)
  8. tino

    February 19, 2021 at 12:09 am

    very interesting your explanation of the transistor
    thumb up dear

    Likes(0)Dislikes(0)
    • Yogesh Panchal

      February 22, 2021 at 6:48 pm

      Thanks! Tino

      Likes(0)Dislikes(0)
  9. biju

    February 21, 2021 at 9:26 pm

    From were you got the capacitor 223j 2kv.

    Likes(0)Dislikes(0)
  10. Yogesh Panchal

    February 22, 2021 at 6:51 pm

    It is easily available in our local electronic component shop.

    Likes(0)Dislikes(0)

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