Hi,i picked this tv up for repair,the initial fault was the side buttons board,it was malfunctioning(ch+ was increasing the volume etc),the owner smartly decided to aim a hairdrier at the board,which melted the plug connector,so he cut it,and thats how i got the TV,though it was going to be simple.
The tv powered by pressing the power button,which is toghether with the remote board.
First thing i did was solder the 3 wires back looking at how it was before
first wire=GND
second=KEY_INPUT1=100mV
third=KEY_INPUT2=3.3V
it did not work,i checked with an oscilloscope,INPUT1 is getting no voltage almost.
Got a samsung remote and it worked fine,the tv was fully operable with it,then all of a sudden it got stuck in store mode.
I entered the service menu and did a reset,it got out of store mode but nothing else changed.
I gave up on it for a few days and now,just plugging it into AC powers on after 3 seconds,the standby led is bliking once per sec,works fine only for 3 seconds,then shuts down,but the standby doens't stop blinking!
The power button now does nothing also with any button,but i can still shut it down via remote,then the SDTBY led stops bliking and is always on,try to power it up,same thing happens,can't mess with the service menu because there's no time for it to reset,maybe it'll only brick the tv even more.
I checked if it was only the backlight shutting down,aimed a flashlight,but no,the image really disappears,seems more like a main board problem.
24V that powers the inverter is fine,all the lamps are lighting up,12V,3.3V,5V,i checked them all with oscilloscope,nothing like bad ripple.
I already cleaned all the grounding points for every board,screws are tight,haven't found cracked solder joint or swollen caps.
Here are the pictures,the wires for the side panel board were soldered in correct order,i tore them apart just now for testing.
The tv powered by pressing the power button,which is toghether with the remote board.
First thing i did was solder the 3 wires back looking at how it was before
first wire=GND
second=KEY_INPUT1=100mV
third=KEY_INPUT2=3.3V
it did not work,i checked with an oscilloscope,INPUT1 is getting no voltage almost.
Got a samsung remote and it worked fine,the tv was fully operable with it,then all of a sudden it got stuck in store mode.
I entered the service menu and did a reset,it got out of store mode but nothing else changed.
I gave up on it for a few days and now,just plugging it into AC powers on after 3 seconds,the standby led is bliking once per sec,works fine only for 3 seconds,then shuts down,but the standby doens't stop blinking!
The power button now does nothing also with any button,but i can still shut it down via remote,then the SDTBY led stops bliking and is always on,try to power it up,same thing happens,can't mess with the service menu because there's no time for it to reset,maybe it'll only brick the tv even more.
I checked if it was only the backlight shutting down,aimed a flashlight,but no,the image really disappears,seems more like a main board problem.
24V that powers the inverter is fine,all the lamps are lighting up,12V,3.3V,5V,i checked them all with oscilloscope,nothing like bad ripple.
I already cleaned all the grounding points for every board,screws are tight,haven't found cracked solder joint or swollen caps.
Here are the pictures,the wires for the side panel board were soldered in correct order,i tore them apart just now for testing.
Attached Files
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