Faq and About Keypad MTK6235 Board version B300-MB-V1.1 xx-xx-xx

On 3 month ago, juni - august I finaly fix more than 200pcs of this phone, and most problem is keypad fault.
So, I make this guide for make easy to repair this problem

Aego i50, GT-MOBILE GT-28, BlackBerry 9000C+, B100, D9000, T900, T9700 and more...
Keypad configuration for this type Board is different with all other model/phone.
Where is the different?? lets roll!!

As we know, all keypad is controlled with voltage (with different frequency like as DTMF) by CPU and CPU was contolled by software (FLASH).
In this guide I write the voltage as "V_Key". :).
(see picture 1)


All(most) phone keypad is Enable (working) when V_Key is LOW (0).
When keypad Unpress, V_Key is HIGH (some volt ~1,8V/other type is different), then when keypad pressed V_Key LOW (0) and keypad working (Enable).

Term and condition almost phone.
Keypad is Enable by V_Key(volt/v) and t(time/ms). Nokia, Siemens, China phone (All CPU type and MTK6235 other board) and other phone.

(see picture 2 and picture 3)



on the picture 2/3, example when keypad number 2 is pressed :
- pressed 1x, appear on display = "2"
- pressed and hold, appear on display = "2 2 2 2 2 ..........2" will stop when unpress the key
- pressed and hold, speaker say = "tut tut tut tut" or "tuuuuuuuuuuuttttttt....." will stop when unpress the key
in sms mode
- pressed 1x, appear on display = "a"
- pressed 2x, appear on display = "b" (on qwerty phone = "e e")
- pressed and hold, appear on display = "2" end of the char (on qwerty phone = "e e e e e e e.....e")
- pressed and hold, speaker say = "tut tut tut tut" or "tuuuuuuuuuuuttttttt....." will stop when unpress the key
(e = is sample char on key 2 (sms))
in this case, when key 2 pressed and hold, then key 3/4/5/other was pressed display will appear "2" cause key 2 is still Enable.

Term and condition MTK6235 Board version B300-MB-V1.1 xx-xx-xx
Keypad is Enable by V_Key(volt/v) as Clock ONLY!!! when V_Key HIGH - LOW

(see picture 4 and picture 5)




on the picture 4/5, example when keypad number 2 is pressed :
- pressed 1x, appear on display = "2"
- pressed and hold, appear on display = "2" cause Enable just once (when keypad first time pressed / V_Key HIGH - LOW)
- pressed and hold, speaker say = "tut"
in sms mode
- pressed 1x, appear on display = "e"
- pressed 2x, appear on display = "e e"
- pressed and hold, appear on display = "e"
- pressed and hold, speaker say = "tut"
in this case, when key 2 pressed and hold, then key 3/4/5/other was pressed display will appear "3/4/5/other" cause key 2 is not Enable.

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Keypad problem on this phone :
* Keypad OK, but Scroll run it self.
* One Keypad not working.
* One row/col not working.
* Scroll OK, but All Keypad Fault (not working).
* TrackBall Fault.
* TrackPad Fault.

Continue Soon... @http://chinesphone.blogspot.com