Sony Xperia neo v won't turn on

[Poseidon_Z]

Hello. I will try to give as many information as i can do so even if the post is big please read it.

So 7 days ago before i get to sleep i turned off my "Xperia neo v" and put it to charge. When i woke up in the morning i tried to turn it on but it wasnt. no signs of life. no leds flashing. nothing.

After that and a small research i finaly turned it on by pressing "volume up key+power", backed up everything(, enabled usb debuging mode, for possible future use) and turned it off to see if it works. Again wasnt turning on even after trying much combinations of buttons.

So after a big research i ended up with a small proccess that can make the phone turn on:

1. Put it on charge for 5-10 minutes.
2. take it out of charge and pull the battery off.
3. wait 4 seconds.
4. put it back.
5. turn on.

so using this proccess i could have access to fastboot and other things that was necesary for my next tries.

the things i tried these days are the following:

• All the possile button combinations.
• Pull out any SIM and SD card and reput in every combination.
• Charge it for 10 Hours straight.
• Pull off the battery for 1 hour.
• Factory reset.
• Flash firmware using Flashtool and s1tool ( NeoV.4.0.2.A.0.62.ftf ).
• Repair with PC Companion ( which also installed the android 4 version [ previews there was the version 2.3.4] ).
• Dissasemply and check for any damage.
• Cleaned and well dryed every hardware component.
• Unlock bootloader.
• Checked eMMC using the "eMMC Check" application ( Brick bug: NO. Sane chip. ).
• While turned on i checked for any hardware error or malfunction ( also used the *#*#7378423#*#* to check stuff and downloaded several applications for health tests).
• All the buttons works perfectly while the phone is turned on.

Thats all i tried. Note that i couldnt yet turn it on with SIM or SD card inside.

My only last suspection is that the RTC battery or a simiral component is destroyed or damaged.

Please answer fast, i will appretiate any help.

Thanks for reading and sorry for my bad english.

[Thommo]

Have you considered that you may have a short somewhere or a dry joint and when these cards are in it's causing a feedback

[Poseidon_Z]

It doesnt turn on regulary with or without any cards. in order to open it with no cards i follow that proccess. but following the proccess with a card on it didnt work. ( also the proccess have a 80% success it doesnt work every time )

also i didnt understood your answer. can you make it more detailed or use other words?

[Thommo]

What part didn't you understand?

[Poseidon_Z]

unfortunatelly all of it sorry

[Poseidon_Z]

What you mean short and whats dry joint

[Thommo]

Short and Dry joint  -  Google is your friend

[Poseidon_Z]

I m so sorry i usually use google but i didnt understand the answer at all. i will search for a short or dry joint in some hours and tell you the results.

but even if there is one how can t sometimes work and some other not?

by the way i am impressed with the how fast you answered. thanks

[Thommo]

If a dry joint is cold then it may turn on then when it gets warm from attempts at turning on the dry joint will expand causing a break in the circuit that's when like the Xbox RROD a Reflow is carried out

[Thommo]

Some may call it a Re-Ball