Sony kd-55xf9005, does it have any uart connections?

[Alex500]

Good evening, I have a bricked sony bravia kd-55xf9005, the motherboard code is 1-983-249-21.
While poking around the web, I came across an old video showing a sony bravia connected to a TTL converter, which in turn was connected to a Putty session.

Is there any chance that my motherboard also possesses a UART input? I found a port that somewhat resembles the one I am looking for; it is located near the optical audio.
If I could get access to the terminal, I could force a firmware update.

Many thanks

[Davi.p]

ok so why don't you try it? left one is gnd, right is 5v, not needed, center ones TX,RX, check the one with voltage is TX, before it check if near it there is a level shifter like max232 similar, or your interface could not work..
ps: emmc or ram could have to be reballed..

[Alex500]

Something is not quite right...
both the center pins have 3.5v, the first pin to the left is actually a gnd pin, the pin to the right the last one has about 4v...

I don't know about the reballing part, it bricked after a failed tcon replacement... the seller sold me the wrong model and I didn't notice it

[Davi.p]

where's the strange with 3,5v? it is low volt serial, not good common pc.Ser port
the wrong tcon cannot damage the software unless you performed an.update with it

[Alex500]

The update is mandatory when performing a tcon swap on a sony bravia tv, so I've performed it.
I've tried to hook up a ttl converter to the port, but unfortunately I couldn't get any communication, I've just found another similar port with similar voltages. I'll try

[Davi.p]

Don't play much with these things, try every keyboard combinations, this is probably Android tv, but in different Sony i found a key sequence for forcing update, even if currrent version was up to date.. today service shops has not much skills, they would not play with serial port..

[Alex500]

You're right...
I've tried multiple keyboard combinations, but the problem is that the tv keeps rebooting at a very fast rate, infact if the tv gets in recovery mode (power button + volume -) the green LED lights up like if it's in PWM... it's so strange

[Davi.p]

PWM=?

[Alex500]

Yes, it's so strange, but the green LED of the tv light up briefly, and if I put my phone camera in slow-mo mode in front of it, it seems like the LED isn't quite on, but it's flickering, just like the PWM controlled LED. I'll attach a video when I get home

[Alex500]

Don't play much with these things, try every keyboard combinations, this is probably Android tv, but in different Sony i found a key sequence for forcing update, even if currrent version was up to date...

Can you remember the combination?

[Alex500]

Sorry, I can't upload videos here... anyway, I've tried the supposed UART port, using a TTL converter and Putty set on 115200 baudrate, but I wasn't able to get any response from the tv...

Doing some research, i stumbled upon a old post
https://www.exploitee.rs/index.php/S...1_(Internet_TV)

This guy is using the same port that I've found...
I guess Sony changed the way to debug their TVs...

I'm still not giving up, I've ordered an hydra emmc reader, as soon as arrives I'll try to read the emmc. Thank you for the support

[Davi.p]

This thread is quite confusing, it's usually best to start with the original symptoms or even the full story.. i make a guess , the tv showed 5 blinks, so you changed tcon, what happens now? how fast the reboot? something on screen? only backlight?

[Alex500]

No.

Basically I found a guy on Facebook who was giving away this sony kd-55xf9005. The problem was that the TV only showed green and red lines on the screen. After a few hours of diagnostics, I came to the conclusion that the T-Con board was the culprit, as it was missing some voltages.
I purchased the replacement T-Con board on ebay for about 15 euros; as soon as I installed it, the TV started flashing orange-green, requiring a software update to pair the main board with the new T-Con. I downloaded the requested firmware, renamed it “upgrade_loader.pkg,” and inserted it into an empty FAT32 USB 2.0.

As soon as I inserted the USB into the TV (USB1), the TV started the firmware update process. It took about 1 hour to complete the whole process. As soon as the TV turned on, I saw that the picture was missing! The backlight and sound were present, but there was no picture. I tried turning it off and on again, but since then the TV has not turned on....

So now I have a bricked TV, showing only a short green light when it is in “hard reset mode (volume - and power button pressed)” and nothing else..

I don't know what to do now... the green LED i'ts strange, because if I point my cellphone camera in slo-mo mode the LED seems to be blinking at a very fast rate...

the rest of the previous posts, are the continuing of this sad story

[Davi.p]

i made some thoughts about the version of you of bad tcon/new tcon damaging MB software, and things doesn not manage to stay straight on feet.. my guess is that you originally hav bad mainboard (bad CPU contacts) so get another MB and replace original tcon back, my advice..

[Alex500]

I made the same guess, I've already ordered a new motherboard, same model and codes, I've installed it but as soon as it did the update, everything went in the same exact way...
so now I have 2 bricked motherboards...

That's why I've ordered the emmc reader, so I can better understand what happened.

My guess is that the tv is trying to start a component on the tcon board that doesn't exist in this model, so it keeps trying to boot but it fails..the uart port was my idea to try to get the boot log so I can see what the tv is trying to do.

Again, I've ordered and installed an incompatible tcon board, but im my defense the seller told me that the model and make was the same...

[Davi.p]

The second Ma.Bo was updated with second tcon in?

[Alex500]

Yes... with the unoriginal one... because unfortunately I was thinking that maybe the cpu was starting to desolder from the motherboard, bad solder balls or the cpu was fried for some reason...

Same tcon, same update (re-download for safety purposes and the usb was reformatted in FAT32), same issue...
the only constant is the unoriginal tcon board...

Both the motherboards has all the voltages, and they seems perfectly fine, nothing shorted or broken...

[Davi.p]

i continue to thinking the wrong tcon cannot have any influence in main software change, my doubt is now the correct file for update.. but rebooting with audio tells the file is not totally wrong.. i'm thinking a bug filled update from Sony, need contact them soon

[Alex500]

All this story doesn't make any sense... It's so strange because the tv booted fine after the update (except for the missing image), and after some times it didn't booted no more..

[Davi.p]

It is strange but quite common, in various brands this happens, killer updates designed with the "bird" or maybe with purpose of destroying sets.. in this sad world this happens.. and nobody does,a thing to contrast..

PS: only add a thing, if main software would be bad, usually led would light 8 blinks, this makes me think there is bad standby sw, check if it is present on a separate memory like a serial flash or microcontroller, normally it is not be written to except in site of updating, but if something is not good with it (solder) then it bricks..