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iPhone Wi-Fi circuit repairing

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This video mainly explains how to find the 2.4G and 5G upper antenna of iPhone XR

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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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When checking the maps, first open the component map, circuit diagram, and bitmap of the iPhone XR

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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 block diagram, 2G_ANT_CORE0 represents the 2.4G upper antenna

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5G_ANT_CORE1 represents the 5G lower antenna

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2G_ANT_CORE1 represents the 2.4G lower antenna

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5G_ANT_CORE0 represents the 5G upper 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,

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and there is no need to search for the lower antenna

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Let's find the 2.4G upper antenna line first

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In the schematic diagram, the third pin of the Wi-Fi chip is the 2.4G upper antenna

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We search for the signal name, the 3rd pin signal is connected to the resistor R7711_W,

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and after the resistor is connected to W2XSW

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The chip is an antenna control chip

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Pin 1 is for power supply, pin 3 is for switch control signal,

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pins 4 and 5 are signals for connecting 2.4G lower antenna

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So when searching, we can only continue to search along pin 7

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Pin 7 is connected to resistor R7713_W,

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and connected to U1900_K after passing through the resistor

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Jump to the bitmap according to the name, after determining the position of U1900_K,

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we look at the component map

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U1900_K is the flat connection antenna on the mainboard

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The antenna is connected internally through the copper wires,

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and the solder points on the lower layer will directly communicate with the solder points on the upper layer.

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So when we look for the signal, we need to look for the signal opposite to U1900_K

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The 1N signal is connected to the resistor R400_W,

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and after passing through the resistor,

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it is connected to the first pin of the filter QPLEX

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The chip is mainly used to switch the antenna signal,

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the 4th pin is the antenna pin

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When using the Wi-Fi function,

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the antenna signal will be switched to the 1st pin of Wi-Fi line

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Other pins are also signals that require an antenna,

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for example, pin 11 is a GPS navigation signal

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We can only continue to search along the 4th pin

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Pin 4 is connected to the inductor L2300_K,

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and then connected to pin 7 of JUAT_A after the inductor

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Jump to the bitmap according to the name, after determining the position,

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we look up the component map

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In the component map, JUAT_A is the upper antenna connector

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In this way, we have searched all the components from the Wi-Fi chip to the upper antenna connector

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When troubleshooting the poor 2.4G signal,

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we can fly the wire directly from the screw post to the Wi-Fi chip, skipping the components

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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