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iPhone Wi-Fi circuit repairing

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This video mainly explains how to find the iPhone 12 Pro Max Wi-Fi 2.4G or 5G antenna line

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Step 1, find the Wi-Fi location number in the component map

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Step 2, search for the Wi-Fi location number in the schematic diagram

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Step 3, find the corresponding antenna pin in the schematic diagram

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Step 4, search for the pin identification in the schematic diagram,

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find the connected components, and finally find the antenna screw post

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We can also jump to the bitmap according to the name to view the connected components

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When checking the picture, we first open the 12 Pro Max component map, circuit diagram, point map

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Find the Wi-Fi location number in the component map

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Then search for the Wi-Fi location number in the schematic diagram

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After finding the Wi-Fi chip, find the corresponding signals

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In the functional block diagram, 2G_C0_ANT represents the 2.4G upper antenna

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2G_C1_ANT represents 2.4G lower antenna

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5G_C0_ANT represents the 5G upper antenna

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5G_C1_ANT represents the 5G lower antenna

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When the mobile phone is searching for a signal,

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it mainly relies on the upper antenna to search for the signal,

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and the lower antenna is only an auxiliary function

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When we check the weak Wi-Fi signal,

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we only need to find the signal of the upper antenna, and there is no need to search for the lower antenna

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Let's find the 2.4G upper antenna line

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Pin 196 of the Wi-Fi chip is the 2.4G upper antenna

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It is connected to the resistor R237_W

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After passing through the resistor, we search for the signal at the back end of the resistor

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After passing through the resistor, the signal is connected to the resistor R463_W,

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and then connects to U_2G_U_W

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The chip is a filter,

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the upper pin is the power supply pin,

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The lower left part is detection and control signals

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When looking for the line, we need to continue to look down from the ANT pin of the chip

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Pin 28 is the antenna pin, ANT

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After the signal comes out, connect to the resistor R461_W

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After passing through the resistor, search for the resistor backend name

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In the schematic diagram, the box that does not identify the coordinates of the pin is the signal conversion box,

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we do not need to check

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Continue to search

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After searching, the line is connected to pin 13 of QPLX4

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The chip is an antenna switch,

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and the other pins are the signals that need an antenna

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When looking for the line, we need to continue to look down from the ANT pin of the chip

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Pin 15 of the chip is the antenna pin, ANT

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After pin 15 comes out, it is connected to the resistor R3904_E

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It is connected to R3905_E after passing through the resistor

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We search for the signal behind the resistor

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After passing through the resistor, the signal is connected to pin 8 of JUAT2

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Jump to the bitmap according to the name,

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after determining the position of JUAT2 in the bitmap, we look at the component map

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In the component map, JUAT2 is the upper antenna connector 2

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In this way, we have searched for all the components connected to the line of the 2.4G upper antenna

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If the Wi-Fi 2.4G signal is weak,

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we can directly fly a wire to the 2.4G upper antenna pin of the Wi-Fi chip

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If the Wi-Fi signal is still poor after flying the wire,

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it means that the Wi-Fi chip is damaged

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Ok, that's all for this video