No Power in Samsung LCD TV with Standby light on-Repaired
One of my relative brought this LN32C450 to me for repair and told me that the power from the house main had gone and after a little while it came back and the TV would not turn on. So first thing I thought that there was an over voltage spike that cause the TV to shut down. So first thing was to carefully plug the TV into my Isolation transformer and see what the systems were.
I notice that the stand-by light was on (See picture below) the switch was getting the 5vdc for the stand-by light to be on. However, when I tried pushing the power switch the TV would not come on. This was the system my relative told me about. I tried to switch it on via the remote control to verify that it was not a problem with the switch, but that did not work either.
This is the Model of the TV – Samsung LN32C450. See picture below.
I then proceeded to remove all the screws from the back of the TV and remove the back case to reveal the boards. Below is a picture of the power supply board. I scan through to see if the was any sign of burn components and did the sniff test. Everything seen to be in order and no visible sign of damage components:
I disconnected the cables from the power supply board that feeds the Inverter board and the cables that feed the main board. I then measured the voltages I got the 5 volts for the standby but when I measured the other voltages it was only reading 5 volts as well. So I concluded that there is a problem with the PSU.
On the picture below is the required voltage that is expected for the PSU to work properly. I began to do some component testing and I check the main filter caps and they were good. I began checking all the caps on the board and found them to be good as well.
I notice that there was a white ceramic capacitor on the board (2J 183J) see below picture.and when I measured it I was not getting any reading with both my Blue ESR meter and my multimeter. I remove the capacitor and place an order for the capacitor. I decided to change all the capacitor on the board as they might fail sometime soon and I don’t want this TV in my shop for a very long time.
Here is a picture of the white ceramic cap.
These are all the Caps on the board I change.
Once I finish replacing all the capacitor I replace the PSU in the TV and tested the voltage I use the light bulb trick and there was no light on the bulb, I check the voltages and they were present. I forgot to take a picture of that. I re-assemble the TV and plug it in the outlet and straight the Standby light came on, so I press the power button and nothing happen but after a few seconds I could hear the sound that the TV was starting up. The TV has a delay start up. So straight away I could tell that the problem was not cause by the power outage, it was just a faulty component.
I left the TV on for about two hours and let it rest and tried it the following day and it work fine. My relative was quite happy with the repair and so was I. Mission accomplished.
Thanks for reading.
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: