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iPhone display circuit repairing

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This video mainly explains how to find the display circuit signals

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and measurement points for iPhone 12 Promax

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Step 1, find the display connector in the component map

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Step 2, find the display connector in the bitmap, and confirm the position number

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Step 3, search for the position number in the circuit diagram,

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and find the corresponding signal in the display connector according to the schematic diagram

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Step 4, jump to the bitmap to view the connected components

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The yellow position in the bitmap can measure the voltage and diode value

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When searching, first open the 12 Promax component map, schematic diagram, and bitmap

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Find the display connector in the component map,

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and then determine the position number of the display connector in the bitmap

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Search for the position number in the schematic diagram

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After finding the display connector,

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find the corresponding signals according to the circuit diagram

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First find the 1.8V and 1.2V power supplies of the display

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Pin 12 of the display connector is the 1.8V power supply

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Jump to the bitmap according to the name,

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the 1.8V power supply is connected to the main power supply through the fuse inductor FL11881

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The 1.8V power supply is shared with the CPU, audio and other 1.8V power supplies

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When overhauling the display circuit, if there is no 1.8V power supply,

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most of the fuse inductors FL11881 are damaged

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The pin 16 of the display connector is the 1.2V power supply

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Jump to the bitmap according to the name,

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the 1.2V power supply is directly connected to the main power supply

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And it is the same way as the CPU and audio 1.2V power supply

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Let's find the I2C bus

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Pin 7 of the display connector is the I2C bus data of the display

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Jump to the bitmap according to the name, the bus data is directly connected to the CPU,

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without fuse in the middle

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Pin 9 of the display connector is the I2C bus clock

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Jump to the bitmap according to the name,

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the bus clock is also directly connected to the CPU,

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without fuse in the middle

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Let's find the 3V and 1V power supplies sent to the display by the main power supply

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Pin 14 of the display connector is the 3V power supply for the display

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Jump to the bitmap according to the name,

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the 3V power supply is connected to the main power supply through the fuse inductor FL11801

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Pin 18 is the 1V power supply of the display

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Jump to the bitmap according to the name,

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the 1V power supply is directly connected to the main power supply,

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without fuse in the line

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Let's find the 32KHz clock signal of the display

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Pin 21 of the display connector is the clock signal of the display screen

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Jump to the bitmap according to the name,

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the 32KHz clock signal is directly connected to the main power supply

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Let's find the reset signal of the display

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Pin 13 of the display connector is the reset signal

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Jump to the bitmap according to the name,

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the reset signal is directly connected to the main power supply,

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and connected to the display power supply

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It means that the reset of the display screen and the reset of the display power supply are the same reset signal

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Let's find the turn-on signal sent by the display to the display power supply,

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VOUT1 2_EN and VOUT3_EN

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Display connector 19 pin is VOUT3_EN

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Jump to the bitmap according to the name,

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VOUT3_EN is connected to the display power supply and the main power supply at the same time

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Pin 20 is VOUT1 2_EN

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Jump to the bitmap according to the name, VOUT1 2_EN is directly connected to the display power supply,

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without connecting other chips

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Let's find the negative 7V power supply sent to the display by the display power supply,

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and the positive 4.6, 7.3V power supply

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Pins 2, 4, 6 of the display connector is the -7V power supply

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Jump to the bitmap according to the name,

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the -7V power supply passes through the resistor R11870 and then connects to the display power supply

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Pins 1, 53, 54, and 57 is positive 4.6V power supply

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Jump to the bitmap according to the name,

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the positive 4.6V power supply is directly connected to the display power supply

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Pin 15 of the display connector is the 7.3V power supply

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Jump to the bitmap according to the name,

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the 7.3V power supply is directly connected to the display power supply

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Let's find the MIPI bus turn-on signal sent by the CPU to the display

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Pin 5 of the display connector is the MIPI bus turn-on signal

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Jump to the bitmap according to the name, this signal is directly connect to the CPU

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Let's find the MIPI bus from the CPU to the display

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Pins 25, 26, 27, 28, 31, 32, 33, 34, 37, and 39 are MIPI buses

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Because MIPI is marked on each line

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The 12 series MIPI bus is directly connected to the CPU, without fuse inductors in the middle

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If the MIPI bus is short-circuited during maintenance,

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it is molt like because the CPU is damaged

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Let's find the TE image synchronization signal sent by the display to the CPU

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Pin 22 is the TE image synchronization signal

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Jump to the bitmap according to the name,

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the synchronization signal is directly connected to the CPU

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without fuse in the middle

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Let's look for other detection signals

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PANICB screen identification signal sent by the display power supply to the display

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Pin 11 is the screen identification signal

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Jump to the bitmap according to the name, the signal is directly connected to the display power supply,

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and no other components are connected

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Next, look for the screen ID identification signal from the display screen to the CPU

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Pin 8 is the ID identification signal sent from the screen to the CPU

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Jump to the bitmap according to the name,

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the ID identification signal is connected to the CPU after passing through the fuse resistor R11818

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In this way, we search for all the relevant signals of the display circuits

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The other signals remaining in the display connector are touch signals,

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which need to be searched only when the touch circuit is overhauled

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Ok, that's all for this video