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40 Inch Samsung LED Television Hit By Power Surge Now Repaired

By Jestine Yong on April 17, 2021

I received a phone call from a caller who was not on my phone book and since I have my business line all over on my webpages and other social handles I always pick the call without paying much attention who is calling.

The caller introduced himself that he got my number from an Uber friend that I do electronics repairs.

I was on my way out of the shop to town to buy spares for the television which was already on my workbench.

Since the caller was around my place, I figured out that since the television has succumbed to power surge according to the information he gave and again power surge damage is usually catastrophic and therefore easy to get culprit since most component failed can be picked using naked eyes.

I decided to wait for him to bring the television to the shop so that I can check the failed components and go check them in town one trip.

Within 10 minutes the client was in my shop. I applied the power as I usually do the initial tests and the television was dead completely, even the power On led was off.

Before opening I was very sure the fuse was gone, I opened the television and this is what I saw.

Like I said you don’t need to use a meter to confirm the above components have failed and therefore should be added to the replacement list. I pulled my meter and headed straight to the main fuse, to my surprise the fuse was okay. I tested across the inputs of the bridge diode looking for shorts and I found its okay also. I check each transistor on the power supply and found them they were all okay.

Then I decided to go to the shop to buy the part but one thing was sure is that getting the line filter(inductor) which was burnt in the market is next to impossible and therefore I usually buy them from other technicians who keep junks of all kinds.

I visited the yard and I was not lucky, while figuring out what next I remembered I had Samsung TV with screen cracked and has stayed in my shop over one year, I decided to go back with other parts which are readily available in town.

Back in the shop, I checked on the junk TV and I was lucky to get the missing part. I installed it together with the two capacitors and applied the power via the series current limiter bulb and the bulb confirmed to me that there is no short on the board.

I decided to test across the output of the power supply and I got voltages and very stable, this put a smile on my face. As I celebrated the easy fix, I decided to question this scenario, how can a brand like Samsung not trigger the fuse to open until the Line filter (inductor) almost went into flames?

Then I remembered my basic electronic something about inductors. See the diagram below.

Basically an inductor function as a filter, which allows low frequency to pass but make it very hard for the high frequencies to pass.

Looking at the circuit above you can see that an inductor is in series with the power line, this means it will allow low frequency of the power supply (50hz to 100hz) and make it very hard for the high radio frequencies to pass.

Although the coils were badly burnt kindly note that the two coils are separated with a small gap between the live and neutral and hence at no point did the two path short and that explain why the fuse did not blow.

Eventually the coil became open circuit and cut the main power from moving forward and hence the dead symptoms.

If you feel you need some in depth understanding on basic electronics, look no further, I have just launched a new online classes on basic electronics at an affordable price here.

Later I re-assembled the power board and applied the power and this is what I saw.

Have a workout week my friends.

Humphrey Kimathi is from Nairobi Kenya and the author of:

1) Lcd-Led television repair guide

2) DVD Player repair guide,

3) CRT Television repair course

4) Basic Electronics Course For Beginners

5) Basic Electronics course.

He is also a blogger at Electronicsrepairmadeasy.com

Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments. If you have electronic repair articles to share with us, please contact us HERE.

P.S- If you enjoyed reading the above article, click here to subscribe to my blog (free subscription). That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks!

Note: You may check out his previous post in the below links:

https://jestineyong.com/ramtons-microwave-model-rm266-come-in-dead-now-repaired/

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22 Comments

Nigel

April 17, 2021 at 3:38 pm

Another satisfied customer! Well done Kimathi! Here in the Seychelles its very hard to get electronic parts thus when I see any kind of PCB by the bin I pick and store as may come in handy for me later and it has been so several times. Thanks for the article and also I have read through your book on LCD-LED television repair guide and it as helped me some much.

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- Humphrey Mndaka
  
  April 17, 2021 at 5:10 pm
  
  Hi Nigel,
  Thanks for your feedback and glad to hear you found my e-book a valuable companion on your workbench. all the best my friend.
  
  Regards Humphrey
  
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David

April 17, 2021 at 4:01 pm

I am surprised there is no mov across the live and neutral and earth. If have then likely it's an even easier to fix.

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- Humphrey Mndaka
  
  April 17, 2021 at 5:05 pm
  
  Hi David, if you look at the photo closely you will see the MOV innocently across the power line but never triggered, again this is strange too.
  
  Regards Humphrey
  
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- Ignatius Ngoma
  
  April 23, 2021 at 4:18 pm
  
  Mr. Kumathi, you never ceases to inspire me, sir! You always hit the nail on the head. Keep it up, sir!
  
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Chris

April 17, 2021 at 4:14 pm

Ashanti sana
========================
Thank you very much

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Albert van Bemmelen

April 17, 2021 at 4:16 pm

I think that the way in how you explained the fuse not being blown although the primary 230VAC filter almost got up in flames is similar to what happens in most SMPS units when they are defect but still have a good primary fuse. Thanks for sharing this nice explained interesting repair.

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- Humphrey Mndaka
  
  April 17, 2021 at 5:13 pm
  
  Thank Albert for your feedback, Always admire your insight.
  
  Regards Humphrey
  
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Parasuraman S

April 17, 2021 at 6:27 pm

Excellent troubleshooting, hunting for spares and finally fixing the TV. Many thanks for your expert observation as well, which is a good guidance!

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- Humphrey Mndaka
  
  April 18, 2021 at 11:54 am
  
  Thanks for your feedback Parasuraman.
  
  Regards Humphrey
  
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  - Joshua Oloo
    
    April 19, 2021 at 4:50 am
    
    Well articulated Hum.you've stated that power surge can be easily identified by naked eyes,Is there possibilities of two filters capacitors failing without necessarily bulging?Thanks and keep the good work.
    
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    - Humphrey Mndaka
      
      April 20, 2021 at 10:49 pm
      
      Thank you Oloo for your feedback, when capacitor Voltage rating is exceeded they usually bulge out the top silvery part. this is one sigh that the equipment was hit by power surge.
      
      Regards Humphrey
      
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Paul

April 17, 2021 at 8:47 pm

Because the same current flows in both windings of the filter, both should been burnt.
Because only one of them overheated, I believe that you had a very rare case that the wire itself was damaged and had a point of high resistance.
If you still have the filter, maybe you can carefully disassemble and check it for the damage.

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- Humphrey Mndaka
  
  April 18, 2021 at 11:58 am
  
  Both were burnt but only one side read open circuit.
  
  Regards Humphrey
  
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Waleed Rishmawi

April 18, 2021 at 1:27 am

That is one long story if hunting for parts that ended up in a very good result. Good job and thanks for sharing

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- Humphrey Mndaka
  
  April 18, 2021 at 12:00 pm
  
  Thank you Waleed for your feedback, long time! Glad to see here.
  
  Regards Humphrey
  
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Humphrey Mndaka

April 18, 2021 at 12:00 pm

Thank you Waleed for your feedback, long time! Glad to see here.

Regards Humphrey

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Yogesh Panchal

April 18, 2021 at 5:21 pm

Good Repair sir,
I also faced many time Circuit components found short circuit and still fuse is intact.......in your case Coil is burnt & becomes open circuit because of high current passing and still fuse is waiting for what????......may be Fuse was not of proper rating.

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- Humphrey Mndaka
  
  April 19, 2021 at 1:38 am
  
  Yes, once the coil burnt it continued working but since the insulation coating broke down it continued to work as a jumper wire until finally one side opened due to overheating.no short occurred between the live and neutral line of the inductor.
  
  Regards Humphrey
  
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lynn blakely

April 20, 2021 at 12:09 am

Humphrey Kimathi : You have explained very well about the practical applied theory of coils to show why the fuse didn't blow. Another satisfaction put into the repaired bag. Thanks for another interesting repair

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- Humphrey Mndaka
  
  April 20, 2021 at 10:51 pm
  
  Thank you Lynn for your feedback, I appreciate.
  
  Regards Humphrey
  
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Humberto

April 30, 2021 at 1:38 am

Thanks for sharing this article.

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