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The phone does not boot , first the first question is to ask the owner , is damaged for any reason , there are several situations in general , Shuaiguo , into the water , causing the charge , or for no reason is not boot , according to the owner feedback over the information to determine where the problem probably . For example , fell a mobile phone, there is no general inspection Weld, or is there any small elements thrown down ; mobile phone into the water , generally the first wash , and then see where the blackened , oxidized , do first treatment ; charge cause not boot , to see if there is any element to the breakdown , and burned out ; unprovoked caused no boot, see if it is a dead battery , or contact problems ;r7iservice manual download site
Of course, if the owner does not offer anything out , it had to rely on our own checks . The second step is to add power test machine (if a water machine, after first cleaning job ) , and see what the current response. The following is my reference to some maintenance information , plus the usual actual repair summed up in several different current response :
A large current does not boot :
Divided into the following two cases:
1 , with the power supply current drain on big : the cause of this failure , usually directly on the phone is connected to B + and component damage , leakage ;
Amp short circuit is generally common , but often this failure are the following models : Ericsson T28, Samsung A188, A408, Motorola T2688;
In addition, the actual repair , I have repeatedly encountered motherboard tail plug leakage and leakage caused by power- B + short to ground phenomenon. Such as : A288 phone plug on the right near the end of the screw hole , board side , often into the water caused by the short circuit board 2 , press the power button a large current response :
The cause of this failure , the power is generally the load branch , while the damaged parts are more diversified , the large components such as CPU, frequency IC, audio IC, font , etc., smaller components such as boost tube , filter capacitor, resistance and so on.
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