K750i reboots itself PLEASE HELP !!!

[lucja]

Hi guys! I have a problem with K750i. I got this phone from a friend of mine. When I try to put in a SIM the phone boots normally , does all things up to "Searching" ... (network) .. finds the network and connects to it and 10 seconds later gives me a White screen and reboots. it look like a software reboot since it takes less time to boot up again. If I remove the SIM and restart the phone without a SIM inside it give me the message "insert SIM" and does NOT reboot. With the SIM out phone stays on indefinitely. I flashed 2 times with different firmware and upgrade once using SEUS. Still the same. After the phone finds the network I still have 10 sec to browse the phone until it restart itself and I has able to play a mp3, make a call , take a picture..All of this are working properly. Everything seems to be working fine in that 10 sec until reboots after finding network. it seems that phone had the joystick replaced recently. I mention that Joystick is working flawlessly. I have CID 36 red.
DOES ANYONE KNOW WHAT IT COULD BE?

[philzfog]

have u used the sony ericsson update service to reflash it
Sony Ericsson - Support - Software - Z555i - Update Service

[lucja]

Yes , I used SE update service from Sony site and I've flashed the latest firmware in.
But the problem didn't correct. I have the same problem . K750i reboots itself after 10 seconds from finding the network. Do you guys have any ideea of what it may be wrong?
please post if someone had the same problem and found the solution.
THANKS

[philzfog]

its sounds like a hard were fault ie sim reader or lcd or battry

[lucja]

Tonight I found a new interesting thing about this phone. I put in a SIM from another country I have (T-mobile) and here there is no T-Mobile network and the phone won't reboot anymore. I put an inactive Vodafone SIM in (there are Vodafone carrier here) and the k750i reboots upon finding signal. To me seems that this has to do with the network. The carrier somehow soft resets the phone. Or, the phone doesn't reboot with T-Mobile SIM since there is no T-Mobile network and RF circuitry is OFF while with Vodafone SIM network is present and RF circuitry is ON (and probably faulty) and that resets the phone.
Any ideeas?

[riders4sia]

try unlocking

[ravenomega]

Is it an unlocked phone? If so try a different SIM card and see if it reboots with it. Im thinking it has smething to do with the SIM.

[lucja]

The phone is unlocked.

[philzfog]

its a hardwere fult with the sim reader and for the phones age u proply could pick up a cheap pcb will be cheaper than have it fixed

[lucja]

The phone is unlocked. The only SIM I found that the phone will NOT reboot itself with, is a T-Mobile SIM. But here where I live there is no T-mobile carrier. So I'm just assuming that the phone tries to connect to a T-Mobile network according to SIM and since is not finding it gives up and shuts off the radio transmitter. It is very interesting that at all times I have 5 bars of signal on the screen (but I have no idea of what carrier's signal). On the screen anyways it shows INACTIVE SIM and the phone never reboots. I tried switching off the phone manually from power button and it switches off BUT it won't stay off.. in a matter of seconds reboots (switches back on by itself). Have any of you guys encounter this problem??
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When I put in a Vodafone SIM the phone searches for network, finds Vodafone carrier, connects to it, and after 10 sec reboots. Is the network rebooting my phone for some reason? or rejecting the phone? Or I have a faulty radio transmitter module and is drawing to much current and the phone take the decision to shut off.
In the 10 second window of time before reboot I was able to receive a phone call and hear the couterpart saying "Hello" so I know for sure Radio transmitter is working (but I don't know if it draws to much of current).
Any new ideas?