Sony KDL55EX720 won't turn on

[budm]

Re: Sony KDL55EX720 won't turn on

I have been looking at the LED power supply board, the one with LED_ON label, that connector then goes to the LED Driver board, I can see one cable sticking out from that bundle of wire to the LED driver board. Is that wire the LED_ON wire? And does it go to the main board?

[tibimakai]

Re: Sony KDL55EX720 won't turn on

That is the PS_ON wire from the mainboard. The connector is unplugged. There is a resistor between the kapton tape soldered in.

[budm]

Re: Sony KDL55EX720 won't turn on

That LED_ON signal must be coming from some where. It may be routed through the LED driver, T-CON or something. It looks like the T-CON is the one that control the Brightness of the LED.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

In the SM it shows board BLK(which one is this?) connector CN1002, now I'm not at the TV, I have to find it online.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

Yes, you were right, it's the left side connector(CN1002) at the LED driver board. So it's turned on by this board, right?

[budm]

Re: Sony KDL55EX720 won't turn on

I need to see the service manual to see what is going on.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

Here it is the smaller size SM.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

Here it is the bigger size, which I can't upload.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

No more ideas?
I have managed to find that regulator, it's not cheap at the end, I had to buy 5 minimum and with shipping and handling, plus tax it will be almost $20, a $0.69 part.
I will buy a mainboard, if nobody has any more ideas. Though, I was hoping to boot up the LEDs to see, that the screen is not cracked at least.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

VDO came in replaced it and getting 3.3V now.
The problem is, the TV still doesn't turn on.
Any more ideas? Should I get a new mainboard?

[tibimakai]

Re: Sony KDL55EX720 won't turn on

How can I be sure that the mainboard it's bad?
How could I turn on the LEDs?
Any help would be appreciated.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

Any more ideas?
How can I test the mainboard to be sure about it's state?
Should I test if it's giving the power on signal, t-con signal, bl on signal?

[tibimakai]

Re: Sony KDL55EX720 won't turn on

I have picked up a board from a different Sony TV, it suppose to be compatible with my TV. Installed it and the standby light turns on and stays on.
I have to turn it on and as soon, as it turns the green LED on, the red LED switches to a 5 blink error code.
In the SM the 5 blink error code shows an HFR error or Panel ID NVM error(T-con error is not used).
Shopjimmy, mentions about a firmware upgrade, actually it's all in red.
I have tried it, but it won't start as I plug it in and if I turn the TV on, it goes right away to the 5x blink error.
It could be, a bad T-con board?
What is your opinion?

[tibimakai]

Re: Sony KDL55EX720 won't turn on

I have tried it without panel ribbon cables and I'm getting the same result.
If I tried, by removing only one side, the green and yellow LED were blinking.
By removing the other side, it's back to the 5 x blink error.
I'm thinking about the blown regulator in the PS, may have damaged something in the T-con?
T-con-12V wants to turn on, but it shuts down so fast that I'm not even able to see a number on the DMM, only the OL.
LEDs not getting any voltage, most likely because the TV senses the error and is not turning them on.
All the 12V, 3.3V stby T-con turn on & 12V is there.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

I'm attaching some shopjimmy pictures of T-con.

[tibimakai]

Re: Sony KDL55EX720 won't turn on

Got another T-con from shopjimmy and still the same, 5 blink error.
If I remove one of the ribbons from the panel, backlight turns on for a little bit, then turns off.
With the other ribbon disconnected, still shows the 5 blink error.
This is weird, 5 error code points to T-con or panel ID error.
Firmware update won't start just in standby state.
Any other ideas?

[tibimakai]

Re: Sony KDL55EX720 won't turn on

I really need some help with this TV.
I have mentioned to shopjimmy, that I have got a different TV's mainboard and they recommended getting the same main board, but this main board is the same as mine, even on the sticker is the same number, which is probably the most important.
Firmware won't load.
I have also posted on a different thread(47EX723), but I will switch back here from now on.

[budm]

Re: Sony KDL55EX720 won't turn on

OK, I will download the service manual and see what is going on. I just fix KDL-32S3000 with 5 blink error code for 12V panel voltage problem, with the help of the training and the SCH I was able to locate blown 5A fuse on the main baord for the 12V that feeds the switched the MOSFET which its output feeds the T-CON.
https://www.badcaps.net/forum/showth...144#post456144

[tibimakai]

Re: Sony KDL55EX720 won't turn on

Thank you, Bud.
The standby vdo was damaged and who knows what else got damaged in the process.
I have picked up this main board, but who knows if it's good or bad, but at least it looks good, since there is a standby LED on and it turns on with a remote.
I don't understand, why it won't take the firmware, it could have already the latest loaded, or it senses an error and until that error it's not repaired, it won't do anything else?
I have a couple of TVs that are giving me a headache.
There is that 65" Sharp, with the tubes lighting up from one end to the other, then I have a 42" Vizio, which I have started up by forcing on the PS and I had backlight, so I have ordered another main board, but it didn't fix it, then there is an older 42" LG with only backlight on.
I will start working on these and I will also need help with these. I have spent money on main boards, T-con boards and it didn't fix the problem.

[budm]

Re: Sony KDL55EX720 won't turn on

So please tell me at this point, what boards (all original?, some original and some are new?) are in the TV. Right now you are getting 5X error, right?