Author Topic: Tv flyback transformer making a ticking noise and tv won't turn on  (Read 562 times)

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Offline Ravichandran

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Hi guys,
I had an old tv which doesn't turn on the display. Also the flyback transformer was making a small smoke. Then i replaced the flyback transformer with a new one and the tv worked fine for few minutes. Then suddenly the tv turned of and the flyback transformer started to make a ticking noise. Still the problem is same. Can you guys help me with finding the problem? :(
 

Offline jjohannes

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #1 on: June 25, 2018, 12:06:15 am »
I'm no TV repair expert, but it sounds to me like you have a short in your flyback. I recommend taking a look at the Sam's Repair FAQ site, it has loads of info on fixing TV:s and has helped me a lot in the past! For instance: https://www.repairfaq.org/REPAIR/F_flytest.html
 
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Online james_s

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #2 on: June 25, 2018, 02:08:55 am »
I would start by looking for shorted semiconductors near the flyback, particularly diodes that rectify the various outputs. Check the soldering on the horizontal drive transformer, and if you have an oscilloscope you should check the horizontal drive waveform. Keep in mind many TVs use a "hot chassis" design so an isolation transformer is needed. 
 
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Offline stj

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #3 on: June 25, 2018, 12:10:36 pm »
check the flyback transistor and all the diodes & electrolytics on the accillary windings for shorts.
 
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Offline andy2000

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #4 on: June 26, 2018, 01:06:24 am »
Is the replacement flyback a genuine part, or a generic replacement?  I have seen generic flybacks fail to work out of the box, or fail shortly after installation. 
 
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Offline lordvader88

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #5 on: June 26, 2018, 06:32:22 am »
Here's a guy with ton's of experience repairing TV's
http://www.youtube.com/user/ATVVideoProductions/search?query=crt+tv
 
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Offline Ravichandran

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #6 on: June 26, 2018, 04:32:35 pm »
it was a generic replacement.
 

Offline Ravichandran

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #7 on: June 26, 2018, 05:18:58 pm »
Also i found out that the horizontal output transistor has burnt.
 

Online james_s

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #8 on: June 27, 2018, 02:30:30 am »
That's a fairly common problem. It can be caused by a bad flyback but other problems in the circuit can make it fail too. The horizontal section is a resonant circuit so everything has to be just right or it smokes.
 
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Offline Ravichandran

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #9 on: June 28, 2018, 01:15:29 pm »
I replaced the failed HOT with a new one and turned on the tv. Then the screen was lighten up for about a minute and suddenly turned off. Then i checked again the HOT and it also has burnt and it was like really hot. What could be the problem? Is it a problem with the replaced flyback or any other component? :-[
 

Online james_s

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #10 on: June 28, 2018, 01:33:51 pm »
It could be the flyback, or it could be the drive waveform, or it could be something wrong with one of the other circuits powered by the flyback. Usually there are a few diodes that rectify other outputs, if one of them shorts it can cause the horizontal output to fail.
 
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Offline andy2000

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #11 on: June 29, 2018, 06:17:20 am »
It's hard to be very specific without a brand and model number, but I would guess you got a defective replacement flyback.  A short on the secondary will usually just cause the set to shut down. 

The fact that the HOT didn't fail until you replaced the flyback also points to the new flyback as the problem. 
 
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Offline Relayer

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #12 on: July 02, 2018, 11:11:28 am »
Hello Ravichandran,
What is the make and model of the telly?
Regards,
Relayer
 
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Offline envisionelec

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #13 on: July 03, 2018, 12:10:36 am »
It's been a few decades since I've repaired a television, but I can tell you that you need to replace the HOT, the flyback, the big blocking diode and the big HV capacitor. Or you'll see this failure repeat itself.

Good luck!
 
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Offline Ravichandran

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #14 on: July 03, 2018, 06:42:49 pm »
My tv model is samsung CS-21Z57ML. Can anyone help me with checking the condition of the flyback transformer which i replaced? Yeah the old HOT was good until i replace the new flyback.
 

Online james_s

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #15 on: July 04, 2018, 03:12:30 am »
Flyback transformers are difficult to conclusively test. I have a ring tester that has been helpful, I think I still have the schematic somewhere, it's not a very complex circuit. You could also build a simple flyback driver with a 555 and power mosfet, but none of these are the same as operating it in circuit.
 

Offline stj

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Re: Tv flyback transformer making a ticking noise and tv won't turn on
« Reply #16 on: July 04, 2018, 03:54:44 am »
you should start by removing the drive transistor and hooking a 60w mains lamp across the B+ line.
that's the supply to the transformer via the transistor.
it should be a stable dc voltage between 80 and 120v dc.
there will be an electrolytic smoothing cap across it that makes it easy to find and solder to.
 


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