Samsung Smart TV Powering On/Off
One of my customers call me on the phone and told me that his 46 Inch Samsung Smart TV was cycling power on and off every 5 minutes and he has no clue what was the problem. Immediately I told him it could that it could have some bad filter capacitors in the power section and told him to drop it off. Below is the information of the TV label.
He brought the TV next day and he told me that he needs it back urgently because his children are on holidays for the Christmas season and I told him that I’ll have it done as soon as possible thinking this should be an easy fix.
Below is some picture of the back with the cover removed.
Power Supply Board.
First thing was to discharge all the capacitors with my homemade capacitor discharge box (See picture below).
After discharging the capacitors, I scan the boards for and sight of physical damage or bulge capacitor and sure enough the was one on the secondary side of the power supply.
I remove the four capacitors that were on the secondary side and tested them, 47uf – 50 volts cap was bulged and I found a 470 uf – 10-volt cap with high ESR. I replace them and reassembled the TV for testing
After I assembled the TV and tested, I was confident enough to say that this TV was fixed. Sure, enough the TV work fine for one hour and just when I was going to call the customer and tell him that his TV was fixed, I saw the same problem that the TV was still powering on/off every 5 minutes. Now I was confused as to what was the problem. I had checked all the components and check all the voltages and everything was fine.
Just when I thought that this was going to be an easy fix I was totally baffled as to what was the problem. I search the internet to see what could be the cause and there was many options and I went through and check all the solutions. It was a bit frustrating so I left the TV and returned to it the next day. I left the TV running for two hours to see if anything was getting hot but had no such luck.
I was using the remote to switch on the TV so one of the internet solutions was that the remote could cause the problem, so I left the TV running and remove the batteries from the remote, but the TV was still cycling on/off. I then tried to switch the TV back on using the power button and immediately I could that around the power switch was getting hot, so I thought it could be the power button. While I was removing the cover for the switch, I notice that there is a small box there. I forgot that this was a smart TV and it had a Wi-Fi card in it. This was the Wi-Fi box that hold the card. See picture below.
This is the Wi-Fi card inside that is inside the box. I remove the outer case and plug the card back in and the metal casing that covers the MCU was getting hot. I then unplug the card and tried the TV and running it for several hours. The problem was gone, the TV was working fine. I call the customer and told him what was the problem and that he can use the TV without the Wi-Fi card. He was using a Fire stick on the TV so he can use a Lan cable and the TV would work just fine until I could get a replacement Card. I ran the TV for a full day and there was no more problem with the TV. After I reassembled the Tv and the customer collected it back, I call him a few days later to see if there was any problem and he said the TV work just fine.
Conclusion: When you think something could be an easy fix, never under estimate what could go wrong. It can be frustrating to fix the problem but never give up. If you are getting trouble, walk away and come back to it another time. It has work for me a lot of times.
This article was prepared for you by Andre Gopee from Calitech Limited Trinidad West Indies.
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Note: Please check out his previous repair article below: