During the maintenance process of Android machines, many machines do not have circuit diagrams. At this time, we need to judge the function of the chip based on our daily experience. Generally, we only need to know the commonly used chips.
Large power supply : The chip with the most large inductors around it, usually with a master clock next to it. The power supply of Qualcomm CPU models generally starts with PM, the power supply of MediaTek CPU models generally starts with MTK, and the power supply of HiSilicon Kirin CPU models generally starts with HI.
Qualcomm power supply IC
MYK power supply IC
HiSilicon power supply IC
small power supply : There are relatively few large inductors around, the size of the small power supply corresponding to HiSilicon power supply is very small and starts with HI, The small power supply of Qualcomm generally starts with PMI or PM... Ending with .A or L and other suffixes.
CPU : Generally the largest chip on the motherboard, most of which are packaged together with the temporary storage. The upper layer is the temporary storage and the lower layer is the CPU. The number HI is HiSilicon CPU, the number MT is MediaTek CPU, and the number QUAL is Qualcomm CPU. Temporary storage of
: is generally integrated inside the CPU or font library. Only a few will be independent. DDR is commonly used in circuit diagrams.
font: is usually next to or on the back of the CPU, and is second in size only to the CPU. It is often represented by EMMC or UFS in circuit diagrams.
charging IC: is generally distributed at the tail plug interface, or on the back of the motherboard. Parts are integrated by small power supplies, one chip, at least one large inductor , and at least one coupling capacitor. The coupling capacitor is connected to one end of the inductor. When this end is powered, the main power supply 4V can be measured. Xiaomi fast charging IC is generally represented by SBM.
Independent backlight display IC: Around or on the back of the display base, there is an IC, a booster capacitor, a bootstrap boost capacitor, any end of the bootstrap boost capacitor is blocked from electricity, and several large capacitors, at least one of which The non-grounded ends of the two large capacitors are connected to the display socket. One of the capacitors, , has a resistance of more than 1000 - OL, and the back-measured resistance is around 500, which supplies negative voltage power to the display IC. (The display IC of some models is integrated with a small power supply or light control display, and the circuit mode remains unchanged)
Independent light control power supply IC: Around or on the back of the display base, a chip, a diode , and a large inductor , both ends of the diode are not grounded, the input terminal of the diode is connected to a large inductor, the output terminal is connected to a large capacitor, the non-grounded terminal of the capacitor is connected to the display base
cold light screen display IC: around or behind the display base, one chip, three large Capacitors, in most models the two inductors look the same, but the other inductor is different. One of these two identical inductors is grounded and is used to start the negative voltage power supply. Two large ungrounded inductors can be used to measure the main power supply. They are easily damaged by water ingress and corrosion, or the path protection components are easy to burn out.
Ringtone amplification IC: One chip, one big point, several large capacitors, the inductor can measure 4V, the inductor is easily soldered due to heavy drop, causing no ringing, two regular protective inductors or resistors, these two protective inductors are generally connected through The speaker contact point on the tail plug.
WiFi chip : distributed around the motherboard, most of them have
independent shielding covers, antenna shrapnel, external interface white
or gray filter switch, WiFi front-end put
amplifier, multiple filter , There is also a
sign next to Huawei WiFi. The WiFi of Qualcomm CPU models generally starts with WCN
, HiSilicon CPU starts with HI, and MediaTek CPU starts with
MT.
Radio frequency part: is generally connected through the antenna buckle of the tail plug on the small board. The shielding cover next to the antenna interface is the radio frequency part. Some models also have a radio frequency part on the back.
IF: is usually inside the signal shielding cover or on the back. Qualcomm models are generally represented by WTR or SDR, HiSilicon is represented by HI, MediaTek models begin with MT, and the pins are generally not visible on the periphery. Multiple inductors and capacitors distributed very regularly.
power amplifier: The inside of the signal shielding cover is about the same size as the IF. There are square and rectangular ones. The square ones are usually GSM power amplifiers with integrated antenna switches, and the rectangular ones are usually mid- and high-frequency power amplifiers. Generally, multiple "√" superpositions or "wells" can be seen on the surface. "No., the pins can generally be seen on the periphery.
power amplifier power supply tube: There is usually a small chip and a large inductor next to or on the back of the power amplifier. Qualcomm models are generally represented by QET or QFE.
audio chip: The audio of Qualcomm CPU is generally represented by WCD. Many audio chips are integrated by power supplies. For example, Huawei HI6555 power supply integrates audio functions. How to find the audio IC through the drawing: first find the tail socket, and then directly use the microphone MIC signal to find the audio.
The component recognition without pictures is not 100% correct. Most models just follow this rule. Some display ICs, charging ICs, and ringtone ICs are integrated by the tail plug board. Don’t ignore the tail plug board when you can’t find it. plate.
