Please guide me to troubleshoot my TV Problem
Sony LED TV
KDL-46EX520
No Picture, but the Sound is OK.
TV Channels are working without picture.
Backlight appears when the TV is Plugged-In
Fuse on T-Con is tested and is OK

Regards.

 

The pcb on the left side is the Backlight inverter board, the pcb on the right is the video/audio processor, start there.

 

Is the set being fed a viable signal... hook up a DVR or other device and get back...

 

Cordial Thanks Dodgydave for your Reply.

Please tell me how can I identify that which board is creating problem i.e.
Backlight Inverter Board, the Video/Audio processor or the T-Con

The Audio is OK . TV Channels are there but there is no Video. Remote is working. Channels can be changed. No indication from Green or Red Lights. Both are stable.

Please advise me Sir.

 

Dear PackratKing, I did try all the options.

I even attached my Laptop as well as my Sony Digital Camera with the TV. They previously worked.

But now there is no response.

Please guide me Sir.

Also note that I'm by profession a Civil Engineer having a reasonably good knowledge of Electronics.

 

Dear I read your profile PackratKing.

You will definitely be pleased to know that I too love electronics. Do experiments, make electronic circuits, devices, circuit boards (PCBs) as well as other mechanical hobby repairs and experiments.

 

Turn on the TV.
wait a couple of minutes while observing the stby LED.
Does it blink ?
If it does, count them.

 

tcon pcb is not at fault-how many times does the standby led flash?what do you get when you press the home key on the remote control?if you get the menu display its localised the fault to a specific board which depending on the fault may scrap the set-if you have no display then it may well be scrap anyway-you need to check voltages on the psu B board(pin1 CN6001-5v for 22"/26" model,12v for the ex model/)
if that supply is there its down to the G board-but check the wiring harnesses first going board to board -also check the logic level of the BL_ON line-at pin 6 of CN6002-if its lo replace the harness from B to G board-if its hi replace the lvds cable connecting the tcon pcb-if you still have no fault found and no display ill talk you thro the rest of the fault finding procedure
depending wether you have deep pockets the next few steps involve detailed examination of the G board or replacement or scrapping the set......I have repaired a few of these sets and unless its done correctly servicing wise you will be going round in circles wasting time if you dont test things in the correct order......

 

Q: how many times does the standby led flash

A: Stand By Light is stable, no blinking

 

Nothing appears on the Screen when I press "Home" on the Remote Control.
But the sound comes that the command has been executed.
TV channels are OK and their sound is clear.

 

have you checked all cables are firmly seated in the connectors from B board to G board and is that supply present on B board,pin 1 CN6001.....either 12v or 5v .....and what is the BL_ON line? The logic level here determines where we go next......

 

Question is, does the backlite comes on?

U can make sure of this from the back of the set. There are holes located all over the back plate. U can see if the back lite comes on or not.
Confirm this.

 

Another way to check the LCD is shine a bright torch from the sides.
If the picture is there, u will see movement of the picture when u look closely and carefully while shining the light from the sides close to screen

 

Dear sheldons:

I've checked the voltage at Pin 1 of CN 6001 and it is 12.35 v

Now please tell me what voltage should I check at other Pins of CN 6001 & 6002

Regards

 

if that supply is there and stable not pulsing its down to the G board-but check the wiring harnesses first going board to board -also check the logic level of the BL_ON line-at pin 6 of CN6002-if its lo replace the harness from B to G board-if its hi replace the lvds cable connecting the tcon pcb-if you still have no fault found and no display ill talk you thro the rest of the fault finding procedure....

 

In the start of the problem, the video came for few seconds and then gone.

I replaced the capacitors as shown. But no effect (No video but only sound).

I also tested and replaced the FETs (KF 5N50).

There is dim blue light on the screen. Sound OK Channels are Tuned, But No Video





Regards.

 

There is a hijacking moved it to here.

 

Problem could be a bad LED in the backlit strip

 

See service manuals for this model:
https://servicemanuals.us/sony/tv/category.html?search=EX520&limitstart=0

 

Sure..After 4 years he will come back to check