Nine, manual intervention method

    Mobile phone repair process, a component damage when the judge , of course, can directly replace the damaged component troubleshooting, but the problem is that some on hand when the component is not difficult to spot or buy , and sometimes have to consider the price components, this when a circuit can be used to change the method to repair the phone , similar to the effect achieved .

    In addition , many of the phone circuits are controlled by the supply voltage and the failure to take maintenance manual intervention , maintenance will be very troublesome, for example , during maintenance -free launch failure , the need to measure the power amplifier , TXVCO supply voltage, etc. when measuring power- boot again , but also to press the launch button , but also with an oscilloscope measurements, could well off , very troublesome. If a signal is applied to TXON high, you can make the amplifier circuit , TXVCO power in continuous operation , although it is not entirely the work of the entire launch system , but they can easily measure TXVCO and power amplifier , to determine the fault very favorable.

    However, the H-level to the TXON , due to the transmission circuit is in operation , there may be a large current should be noted that energization time not too long .

X. pressing method

    Phone uses a lot of BGA package IC , these BGAIC easily fall due to thermal expansion caused by factors such Weld, causing the phone does not boot, no network, no display , does not know the card fails, then , is how to determine the fault BGAIC Weld caused it ? maintenance , can be pressed law judge. Upcoming doubt BGAIC with a rubber compression , and then boot, failure to see whether the changes , if any changes , then the BGA-IC exists Weld, and then blow the BGAIC be welded or vegetable tin.