Problem Analysis:
Why is it always that support teams are never supportive and always useless? Seems this is a secret of the universe we will never know about... 
As you know, most of us are complaining about 2 huge problems in Sony Xperia Tipo Dual:
- The strange battery drainage problem which makes the phone lasts only for like 7 hours in standby mode even without doing anything, while it is supposed to last for at least 24 hours with normal usage (browsing, music, etc...).
- Whenever there is a data transmisson going on SIM1, the phone shows no signal on SIM2, and once the data transmission stops for a few seconds on SIM1, it reconnects SIM2 again.
Turns out that both problems are actually connected together! As the continuous connect/disconnect pattern of SIM2 causes the very famous "Time Without a Signal" problem (which our great and knowledgeable support team apparently knows nothing about), this problem is simply that whenever the phone tries to re-connect it keeps looking for the network's nearest tower etc..., thus draining the battery at a horrible rate, just 1 byte of data transmisson on SIM1 would be very enough to cause SIM2 to disconnect, and then it tries to connect again, etc, it goes on forever without stopping.
You can check it for yourself by going to Settings/Battery/Cell Standy and check the "Time without a signal", mine reached upto 60% while it is supposed to be around 0-1% maximum.
Problem Solution:
So how did I solve this? Simply by changing the way the mobile connects to the networks you solve both problems.There is a direct way which does not give a lot of options and an indirect way for advanced users.
The Easy Way:
- Open the Settings window.
- Under "Wireless & Networks" click "More...", and then "Mobile networks"
- Click "Select SIM card" and select the SIM card you would like for data transmisson.
- A new window should pop up, click "Network Mode".
- Choose "WCDMA (preferred)/GSM".
This will cause the phone to try to connect 3G first on your data SIM before it tries 2G, apparently the mobile has some bug which does not allow 2G connections on both SIMs in the same time, but this option will cause your data SIM to connect 3G and the other one to connect 2G which eliminates the problem.
The Hard Way:
So if the WCDMA mode is not available for your network, you may want to try the advanced solution which gives plenty of other options to choose from.
Warning: This step involves messing with the phone's secret testing menu, so if you don't know what you're doing don't mess with it because it can cause problems, don't say I didn't warn you.
- Open the dial pad (phone icon) as if you are going to dial a number.
- Write this code: *#*#4636#*#*
- Click "Phone information"
- Scroll down until you see "Set preferred network type", open the combo box you will see many options, you can try the most famous ones like: GSM auto (PRL), CDMA auto (PRL), GSM/CDMA auto (PRL), but remember what the original choice was so you can get back to it whenever you mess it up (it will usually be GSM only as it is the main reason for our problem).
- Make sure the phone changed it by looking in the "Phone information" menu, because sometimes it reverts back to the older setting without a reason.
- Exit and restart your phone.
- Keep trying until one of them works for you.
For more information about the connection modes, check these links:
http://blog.ruggedandmobile.com/2010/01/26/a-guide-on-the-difference-between-gprs-edge-3g-and-hsdpa/
http://www.edaboard.com/thread57629.html
After you do the trick, charge your phone from AC adapter fully, then disconnect it, and keep an eye on the "Time without a signal", it should be around 0-1% maximum, watch the battery drainage pattern, and the signal on both SIM cards, they should be working great now.
Please share your experience with us and tell us what happened when you tried it.
:smileyangry::smileyangry::smileyangry: THANK YOU SUPPORT TEAM :smileyangry::smileyangry::smileyangry:
Regards,
Andrew George
Egypt
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