A, automatically boot?
With the battery, do not press on / off key opened the boot state. Mainly because of the open / short circuit to ground or key boot line to ground short circuit caused by other components. Remove the mobile phone board, use alcohol foam after cleaning, mostly can solve this fault.
Two, automatic shutdown (automatic power-off)?
Automatic shutdown 1 vibration
This is mainly because the battery and the battery contact piece contact caused by bad.
The 2 key shutdown
Mobile phone as long as no keyboard, mobile phone can not shut down according to a certain key mobile phone will automatically shut down, mainly due to weld CPU and memory, strengthen welding on memory CPU and memory in general can solve the problem of.
3 emission shutdown
Mobile phone press the launch button automatic shutdown, are mainly caused by the power amplifier part of the fault, is due to the general power supply IC (or power amplifier control) caused the fault
Three, emission, emission out weak signal?
The launch of 1 weak
Mobile phone in standby state, do not show the weak electricity, telephone, or make a few calls immediately after the show to appear weak, low power alarm phenomenon. This phenomenon is due to the battery with the first contact piece interface is dirty or poor contact caused; second is the contact interface battery contact piece and the mobile phone circuit board caused by bad; the second is the amplifier itself damage caused by.
2 launch off signal
Mobile phone in standby state, normal mobile phone signal, a signal transmitting fell out, this phenomenon is due to the fault or damage caused by mobile phone amplifier weld.
Four, the leakage?
Mobile phone is difficult to repair the leakage fault. Firstly judging power part, a power switch tube is burnt out caused by short circuit. Secondly, to judge whether the damaged power amplifier. Secondly, the leakage current is too much, to the phone and add power 1 ~ 2 minutes later with the back of his hand to feel what part of the heating element is serious, this element will be bad undoubtedly, replace it. If there is still above method to solve the fault, only to find whether the line short circuit resistance, capacitance or printing line.
Five, the net?
No network can be divided into signal without signal mesh network, two cases. Currently on the market with Ericsson, Samsung mobile phone series, as long as the receiving channel is good, there will be a signal strength value display, and there are no emission signal is independent of other series, mobile phone must wait until the phone into the network after the display of signal strength values. The series of other mobile phone in judging the fault range, to the mobile phone plug in SIM card, adjusting the menu, find the network, with a manual search method at this time, can find network, prove that the receiving channel is good, is to launch the channel fault caused by the network; using the menu method cannot find network that receiving channel is faulty, the first maintenance of the receiving channel '
Six, signal instability (off signal)?
Because the receiving channel components (weld caused by falling over phone prone to this fault). Mainly to the receiving filter, saw filter, if filter and receiving IC components such as welding, are able to return to normal.
Seven, software fault?
To sum up, the main mobile phone software failure phenomenon:
1 mobile phone screen display contact service, return the factory maintenance information software malfunction, rewriting code sheet data.
2 no boot, boot current meter pointer to indicate the current than the normal value of about 200mA a lot, but release the power button ammeter pointer back to zero, this phenomenon indicates that the power supply part is basic and normal, clock circuit is not working properly or CPU is not working properly.
3 no boot, boot ammeter pointer indicating the current about 200mA a moment right back to 0mA. This is a chip data of typical disorder caused by software does not boot failure
4 press the power button is about 20 ~ 30mA leakage current, show that the power supply part and elements are short or damaged.
5 press the power button to have large leakage current indicates that the power supply part short circuit or power amplifier part damage components.
6 plus battery leakage, first remove the power integrated block, if no leakage, indicating failure caused by power supply IC; if still leakage, illustrate the fault by the battery positive direct power supply components damaged or the electricity line its short-circuit (water prone to cause this fault). According to the battery for mobile phone power supply principle of detecting lines or components (power supply filter capacitor, power protection diode can appear sometimes short).
7 mobile phone can work, but the standby current is much bigger than normal. Troubleshooting this failure is: power up phone, 1 ~ 2 minutes with the back of his hand to feel what the heating element, its replacement, in most cases, troubleshooting. If still cannot be ruled out, whether a load circuit search the heating components and elements are damaged or other power supply components are damaged.
8 no cell phone signal strength indicator or no network, according to the approximate range table pointer swing current fault diagnosis. Under normal circumstances, find the network at the same time in the mobile phone, ammeter pointer swing without stop, amplitude is about 10mA. If the ammeter pointer is normal, there is no network, this failure is more common in NOKIA, Motorola and other mobile phone, the scope of fault are mostly in the emission part VCO or power amplifier circuit part; such as ammeter pointer is not normal nor the signal strength indicator, then the fault range mostly in the other part of receiving VCO, the vibration part or receiving channel.
Eight, does the mobile water how to do?
Mobile phone after water, but don't touch any key, also do not use button to shutdown, the first to do is to open the cover, remove the battery, forced outages, and then processing, dry. Because a any key, the water will enter the interior, this is my friend has just sent me the life tips. Must not