Sony KD-55XF8505 won‘t start

[Davi.p]

Re: Sony KD-55XF8505 won‘t start

Let's try to understand something, after that its up to you your choice, this mb appears to be without any tcon integrated, this is clear for me by a series of details, the big Mstar white chip is the FRC processor, not Tcon one, so the 2 eproms in photo are 1 for FRC operations, the other i don't know but by exclusion it can hold standby sw, it is not surely a bootloader cause no activity on the status led means bad stby sw.. if you want to trust me you can start my tests, otherwise i don't know why since you came here because with no ideas.. or you can wait the second board to read the flash by it, since freezing only works sometimes..

[TobiasG]

Re: Sony KD-55XF8505 won‘t start

Let's try to understand something, after that its up to you your choice, this mb appears to be without any tcon integrated, this is clear for me by a series of details, the big Mstar white chip is the FRC processor, not Tcon one, so the 2 eproms in photo are 1 for FRC operations, the other i don't know but by exclusion it can hold standby sw, it is not surely a bootloader cause no activity on the status led means bad stby sw.. if you want to trust me you can start my tests, otherwise i don't know why since you came here because with no ideas.. or you can wait the second board to read the flash by it, since freezing only works sometimes..

The working board for my TV (with the same part number) should arrive tomorrow. Then I'll also try the the dumping of the eeproms and reflashing the dumps to my old board, since it might lead to me saving money because I can then send the new board back.

Anything else would be stupid, or

I also considered checking all the electronic parts again with the values i will messure at the new board and maybe I'll still find the error on my old board.
But if it still doesn't work, what else could it be?

[lotas]

Re: Sony KD-55XF8505 won‘t start

Let's try to understand something, after that its up to you your choice, this mb appears to be without any tcon integrated, this is clear for me by a series of details, the big Mstar white chip is the FRC processor, not Tcon one, so the 2 eproms in photo are 1 for FRC operations, the other i don't know but by exclusion it can hold standby sw, it is not surely a bootloader cause no activity on the status led means bad stby sw.. if you want to trust me you can start my tests, otherwise i don't know why since you came here because with no ideas.. or you can wait the second board to read the flash by it, since freezing only works sometimes..

I figuratively said that this MStar chip belongs to T-Con, since the output, signal lines go to the panel (t-con) and it cannot be responsible for the standby mode, and these two SPI Flash just relate to this MStar chip, as their position numbers start with IC4xxx.

[Davi.p]

Re: Sony KD-55XF8505 won‘t start

as their position numbers start with IC4xxx

yes this is a good point for you, in meantime i noticed there was also a picture of the stand alone tcon, the MStar chip is the FRC not the tcon, it sounded strange to me it required till 2 eproms to work but it is probably right.. at this point it seems this is an "always on" Android tv and the bad software is the main/only sw in the emmc, so this worths a typical test of the android devices and is trying to access recovery mode with keys combinations, if not done i suggest research of service manual cause entering could include both RC keys and local keys pressed, i think the main key possible on RC is the power key, then togheter another key on the local keyboard, try different combinations and see if starts.
other possible tries are PC connection through ADB utility and usb, or uart connection and log viewiing , but this is for high end techs..
another mention for the ic605 near the emmc, this is probably the reset ic, it must be probed if a good reset signal is send to the Cpu during the plugging of the tv to mains..

[TobiasG]

Re: Sony KD-55XF8505 won‘t start

And what does that mean for me now?
Is it probably the eMMC?

[Davi.p]

Re: Sony KD-55XF8505 won‘t start

yes it is..

[TobiasG]

Re: Sony KD-55XF8505 won‘t start

Do you think that the chip is defective or the data it contains, or could reflowing help?

[Davi.p]

Re: Sony KD-55XF8505 won‘t start

i think only data is corrupted, it can be revived by a deep clean and rewrite..

[TobiasG]

Re: Sony KD-55XF8505 won‘t start

With the new mainboard everything works fine.
Maybe I will try later, if it is possilbe to read the emmc from the new one and write it to the old. Maybe it works with less deep engagement

[lotas]

Re: Sony KD-55XF8505 won‘t start

With the new mainboard everything works fine.
Maybe I will try later, if it is possilbe to read the emmc from the new one and write it to the old. Maybe it works with less deep engagement

Be careful, when reading the dump, some programmers change the contents of the "EXT_CSD" file, and after that the TV will no longer turn on.

[nomoresonys]

Re: Sony KD-55XF8505 won‘t start

ok, with that being a possibility, I would just be happy with the new board and the tv working, would save the old board, not really worth the risk of messing up the new board. If you have or can find a good dump, maybe just buy a new emmc and try that for the old board, I think they're around 15 bucks or so, at least that's the price that I saw.

[TobiasG]

Re: Sony KD-55XF8505 won‘t start

Unfortunately, the firmware for the board cannot be found on the internet. I've searched on Russian sites myself. but they seem to have installed other mainboards

[nomoresonys]

Re: Sony KD-55XF8505 won‘t start

can get them preprogrammed, about 50+ U.S. dollars. seems a little high but haven't seen them for less.