Sony KDL 52w5500 No image, no Backlights

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

ok I tested the CN6204 on the power S. Board
and it doesn't get any backlight signal
Would it mean that the main board is at fault, and that changing it is my best shot ? :s

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

So what do you get at the BACKLIGHTS pins? The reason for the BACKLIGHTS pin to be LO can be:
1) No signal from the main board.
2) It is locked out due to fault in the power supply board.

So you need to check the voltage on the Cathode side of the diode as shown in the diagram to see what you have.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

I get nothing (same as CN6201 0,001 and 0,002)

Case 1: I need to change the main board ? (damn, that the most expensive part from what I see on the net)

Case 2: I should get then an error code for the Power supply board for being at fault ?

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

You need to verify the voltage at the Cathode of D6206 as shown in the diagram first, it should be close to 5VDC.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

hum, I don't find any D6206 reference neither on the diagram neither on the power supply board directly
Which diagram are you using ?

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

Post 42, the power supply board used in your TV is the same as used in 52V5100 as I have listed in post 31.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

Oh, ok this was the post where the doc was not attach first.
Alright I did found On the back of the board the reference to D6206 but I'm not sure on how to proceed the test
I've no clue on how to test this component

Am I suppose to run the TV with the power supply board on the back to test D6206 directly from the circuit side ? This feel a bit unsafe, but if it's the way to do it, I'll :s

http://entrepot2.free.fr/tv/D6206.JPG

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

Hummm so this seems to be a "high speed switching diode"
The only example I foud on the internet is to see if the diode is working corectly
And I do get a 0.5 volts as a result
So I'm guessing that it's not really what you wanted me to test

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

You can check the voltage right at the two pins (3 & 4 on the secondary side of the power supply board) of the opto PH6501, just make sure not to slip the probes!, you will have to power up the TV.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

Thx
So I've 3,39 VDC

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

OK, that is fine, so that means the BL_ON was not locked out but it is not present from the main board.

[audiofreak19]

Re: Sony KDL 52w5500 No image, no Backlights

So does that mean its something on the main board not allowing the back light to turn on.

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

Yes, please see your post because I would like to know what you get at the backlights pin.

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

I am working on this post also:
https://www.badcaps.net/forum/showth...t=36482&page=2
If we can get one of you to work, I am sure we can get both TVs working, since both of you have the same power supply/inverter boards.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

Thx again for your help
Just as a reminder, compare to audiofreak19, I also have my T-CON that is not working properly
And I do have sound.

For now what we know is:
The backlight message should be routed correctly on the power supply board.
No backlight signal is going through the power supply board.
I also did test the CN6204 to see if it's getting a signal from the main board, and it's not

So from my understanding, the problem doesn't seems to be from de power supply board

@budm: Do you know what is suppose to be the trigger for the main board for sending the backlight signal ? Is it just the power on ?

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

The processor is the one that generates the signal after the TV is tuned on and pass the self test mode, but I am not 100% sure if there is anything else that can lock out the the BACKLIGHTS signal.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

The processor is on the main board I suppose ?

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

Yes.

[goulloux]

Re: Sony KDL 52w5500 No image, no Backlights

Ok thx a lot for your help, I guess I'll try to find this main board now
Do you know any website that would allow me to find all the tv that have the same main board ?
I've more success in searching "KDL-xxxx main board" than using the board reference directly :s

[budm]

Re: Sony KDL 52w5500 No image, no Backlights

As I study more circuits of this TV, there are other signals or circuits that can also lock out the BACKLIGHTS signal.
See the info I added here:
https://www.badcaps.net/forum/showth...628#post435628