Can't power on the device after getting it back from service

[Maly12340]

Witam, wysłałem xperie na gwarancję(odklejający się przód i tył, nie działające nfc i skaner linii papilarnych), w serwisie dowiedziałem się że telefon był naprawiany w innym serwisie i dostałem informację że naprawa będzie kosztowała około 2200 zł, wybrałem opcję odesłania urządzenia bez naprawiania, otrzymałem nie włączającą się xperię z mrygającą czerwoną diodą podczas ładowania. Proszę o pomoc.

Hello, I sent xperie for warranty (peeling off the front and back, non-working NFC and fingerprint scanner), I found out that the phone was repaired in another service and I received information that the repair will cost about PLN 2,200, I chose the option of sending the device back without repairing I received a non-running xperia with a flashing red diode while charging. Please help.

-GT

[schetz]

Have you tried connecting it to PC with volume down pressed? While Xperia companion is on.

Have you tried holding volume down+power without connecting it to PC?

[Maly12340]

I tried these methods and others, I checked the voltage with a multimeter and is still 0.2V. I gave the phone back to the service for replacing the battery.

[Maly12340]

after connecting the phone to the computer, nothing happened, you could not enter it in any communication mode, nothing was responding only the LED was flashing

[schetz]

When that happened on my z3 , repair centre replaced battery too. But couldn't power it on still, as it drained while on the way back to me.

Turns out they had to replace motherboard. Third hand info said, some battery draining controller is on motherboard, which was faulty, and allowed battery to drain below safe level. 

Now, I'm not sure that's correct, but made a bit of sense, and it worked so..

Moral of the story: try to drain your battery after replacement, just to be sure.