Check out this link below to download a PDF manual, software, and more for your phone. Just copy and paste into your browser.
http://www.samsung.com/us/consumer/mobile/mobile-phones/t-mobile-phones/SGH-T819CNATMB/index.idx?pagetype=prd_detail&tab=supportChange Phone Password from page 150 in your manual:
The Change phone password feature allows you to change your current phone password to a new one. You must enter the current password before you can specify a new one. Once you enter a new password, you are asked to confirm it by entering it again.
You can try this:How Do I Reset My SGH-T819?
To Reset the handset, to the factory default Settings, follow the steps below:
- While in standby mode, press the left soft key for Menu
- Select Settings (9)
- Select Reset Settings (#)
- Press the OK button to check the box(es) for the following:
Press the left soft key for OK
Enter the password, using the keypad, default password is “00000000”
Press the left soft key for Confirm
Press the left soft key for Yes to reset the handset
- All: Phone, Display, Sound
and Alarm settings will be reset to the
- Phone settings: Only
the Phone settings will be reset to the default
- Display settings: Only the
Display settings will be reset to the default
- Sound Profiles: Only the
Sound Profiles will be reset to the default
Only Alarm settings will be reset to the default
If all fails you can contact Samsung at the above site in live chat or call them at 1-888-987-4357.
Hope this helps, let me know if I can help you with anything else. It would be very kind of you if this does work for you to please rate me or leave a short note. I would really appreciate it. Thank you for your time.