Samsung TV LN46A650 turning on and off.

[salilsurendran]

Hello,
I have a Samsung TV LN46A650 which was connected to a PC. It had recycled itself a few times. At that time I thought this was an issue with the video card getting too hot and I shutdown the computer and after sometime the problem would be gone. This issue would happen very rarely. However, I connected it to a Roku box about a month ago and it has started turning on and off more frequently. I thought it was the capacitor problem that people were talking about and called Samsung. They sent a technician who said that all my capacitors were fine. he replaced it anyway but still my TV keeps giving me the same problem. I tried connecting my laptop to the TV and that has the same problem. It won't even work when connected to an aerial. Sometimes it will work for sometime and then randomly switch on and off. Sometimes it will make a jarring sound and then turn off. I checked the power supply with a multimeter and tried HDMI and AV output ports and also different power supplies same problem.
I opened up the TV and with a multimeter I tested the voltages produced by the Power Supply board and saw that only PIN 3 produce 5.19 V all the other ports showed a solid 0. I was wondering as to how can this be the case since my TV does recycle but still does turn on sometimes. Other thing the board is labeled as 'IP-271135A' which translates to 'BN44-00202A' but shopjimmy.com says this is a substitute for 'BN44-00203A'. Is the problem that Samsung put a substitute part in my TV instead of the real one. I am going to buy a new power board. Which one should I buy the 'BN44-00203A' as specified by shopjimmy.com or the existing one in my TV 'IP-271135A'

[drpj23]

Re: Samsung TV LN46A650 turning on and off.

You are probably checking the p/s in standby and therefore only that voltage will be present. You need to cut the TV on to test the others. You can post back with results in respect to the legend (since we are not looking at the board or include pictures)
It more or less sounds like main problem but it would be good to verify the power supplies voltages.
TVs also use many variations of boards depending on when it was made and revisions etc. ShopJimmy is just saying that the other board can work as a substitute for your original.
Lastly, try a reset.
With the TV off, press mute, 1, 8, 2, and power (in that order) and you should see the factory menu and find factory reset.

[randtek]

Re: Samsung TV LN46A650 turning on and off.

The "turn on" and "turn off" chimes on a Samsung can help you to diagnose these kinds of problems

When failing, does the TV make the "turn off" chime? Does it make the "Turn On" chime when it turns itself on? You say turning on and off. Do you mean it just randomly turns itself *ON* when you are not operating the TV? Or does it only turn itself off when you are watching it, and then turn itself back on? The answers to these questions can help determine the issue. Here's how:

If the TV just randomly turns itself on (or off) with no input from remote or panel buttons, and makes the proper turn on/off sound, it indicates the TV "thinks" it has been told to turn on or off. suspect remote interference, a bad IR/functions board, or a main board issue. Remote interference is where the IR sensor is triggered, due to spurious IR hitting the sensor. This is often caused by Fluorescent lighting, or even sunlight coming through a window hitting the IR sensor.

If the TV turns off without making the turn off chime, then comes back on and makes the turn on chime, suspect an intermittent power board issue, or possibly ground connections between the power board and panel (screw hole grounds). The TV is losing power intermittently, but the Main board tries to immediately turn itself on because Samsungs "remember" their on/off state when the just lose power.

If the TV turns off and on without making either turn off or turn on sounds, suspect a main board issue.

[tom66]

Re: Samsung TV LN46A650 turning on and off.

I would note though that I have encountered a few Samsung TVs where the user has turned off the chime (it is possible to turn it off from the menu.) This can mislead one into thinking it is a main board issue.

[randtek]

Re: Samsung TV LN46A650 turning on and off.

You are correct Tom. A small percentage of sets do come in with this setting turned off. That is just one reason why I nearly always do a factory reset on a TV that has any type of control issue, once I have verified the customers complaint. That quickly eliminates a configuration issue as part of the problem.

[salilsurendran]

Re: Samsung TV LN46A650 turning on and off.

When I turn on my TV, it will recycle on and off without any input from me. After a few cycles which could be anything from minutes to hours it will turn on but the picture will be distorted or will get distorted after some time. After which it will start recycling on and off automatically. This happen with any kind of input Roku, laptop, TV antenna etc. I believe the TV is turned on when I get on voltage on all other terminals except standy but I will check again.

[tom66]

Re: Samsung TV LN46A650 turning on and off.

You are correct Tom. A small percentage of sets do come in with this setting turned off. That is just one reason why I nearly always do a factory reset on a TV that has any type of control issue, once I have verified the customers complaint. That quickly eliminates a configuration issue as part of the problem.

If you cannot see the display, how do you do a factory reset?

[randtek]

Re: Samsung TV LN46A650 turning on and off.

If you cannot see the display, how do you do a factory reset?

I should have qualified that, as to whether TV would display correctly or not. I was under the impression in this case that at least some of the time this TV would display. I could be mistaken there. There are ways though. for many sets, I have created "blind" reset procedures, by recording the EXACT steps/button presses required to reset a unit. I can usually tell by the behavior whether TV has actually reset or not. For some TV makes, you can buy or make a "Factory" remote that will control things unaccessable through normal means. This option is usually not available to the do-it -yourself-er. Due to the nature of my job, I am usually rushed when I make posts on here, and don't always have time to think of/post all caveats. Especially things that I do so often I hardly even think about them. Sorry for any confusion this may cause. i will try to be more careful in the future.

[salilsurendran]

Re: Samsung TV LN46A650 turning on and off.

You are probably checking the p/s in standby and therefore only that voltage will be present.

Yes you were correct the TV was in standby mode because I had disconnected the main board from the PSU. Once I connected it the voltages at the other terminals appeared. I couldn't test the voltages to the main board though since the connectors wouldn't let me touch the terminals.

[tom66]

Re: Samsung TV LN46A650 turning on and off.

When the connector is inserted a small metal sheath is visible around the pin, probe there instead.

[salilsurendran]

Re: Samsung TV LN46A650 turning on and off.

Lastly, try a reset.
With the TV off, press mute, 1, 8, 2, and power (in that order) and you should see the factory menu and find factory reset.

Tried to reset using this method but it didn't work.