samsung flashing/flickering/strobing

[budm]

Re: samsung flashing/flickering/strobing

So the PWM is still varying, correct? If it is then that is what causing the flickering.
Did you try resetting the TV in service mode, I do not know what the key combination on the remote control has to be to enter service mode for this model.
BTW, is there local dimming function or other functions as shown in this link?
https://www.samsung.com/au/support/t...ming-on-my-tv/

[zuehls]

Re: samsung flashing/flickering/strobing

Yes I have reset in the factory menu.
I don't think this TV has local dimming...cannot find it in any menus.

[nomoresonys]

Re: samsung flashing/flickering/strobing

Test pin location 2 of the connector cable for continuity from end to end, careful not to distort the terminals, just in case there might be a problem in that wire.

[nomoresonys]

Re: samsung flashing/flickering/strobing

Try plugging the tv right into the wall outlet if you have not already, see if it stops and unhook all accessories like dvd player etc.

[zuehls]

Re: samsung flashing/flickering/strobing

What I did:
1. Reattach mainboard to power board
2. Power on unit
3. Measure pin 2 @ CNM803 PWM_DIM and I got 2.02v (steady) UNTIL screen starts flickering (about 10 seconds). When screen is flickering the voltage fluctuates between 1.79 and 2.2v and it never settles down while the screen is flickering.
4. I also measured the same pin on CN201 (mainboard) and it has the same readings as the power supply and it is steady at 2.02v until the backlight starts flickering and then it's voltage also fluctuates between 1.79 and 2.2v.

Another test...

1. Power off unit
2. Detach mainboard from power board
3. Turn unit on
4. Measure pin 2 @ CNM803 PWM_DIM and I got 3.17 (steady) never fluctuates

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Is the mainboard causing the power fluctuation or is the power supply causing the fluctuation? Would that indicate which board is bad? Also, I noticed that when I adjust the backlight in the TV settings that I am not able to detect any noticeable dimming or brightening of the backlight. Does that mean anything?

thx

[nomoresonys]

Re: samsung flashing/flickering/strobing

Seems like the mainboard is causing it?? Can you trace the 2 pin back on the mainboard, see what it goes to?

[zuehls]

Re: samsung flashing/flickering/strobing

I traced pin 2 on CNM803 (PWM_DIM) to the mainboard CN201 connector. It's behavior is documented in step 4.

4. I also measured the same pin on CN201 (mainboard) and it has the same readings as the power supply and it is steady at 2.02v until the backlight starts flickering and then it's voltage also fluctuates between 1.79 and 2.2v.

[zuehls]

Re: samsung flashing/flickering/strobing

I replaced the mainboard and the problem still remains. Any thoughts?

[zuehls]

Re: samsung flashing/flickering/strobing

For the benefit of others this problem was resolved by replacing the t-con board. No more flickering. All the controls, like the backlight are also functioning as designed. Thanks for the assistance.

[nomoresonys]

Re: samsung flashing/flickering/strobing

Nice work, that's why I don't mind grabbing a cheap tcon board, many times it fixes symptoms that aren't even typical of a bad tcon, those symptoms seemed like a powerboard , backlight or mainboard problem BUT nope just a bad tcon.

[nomoresonys]

Re: samsung flashing/flickering/strobing

Looked back over the thread, looks like the only thing we missed trying was detach tcon from mainboard and check for the voltage fluctuation.