Compared with the iPhone 11 series, the motherboard separation of the iPhone 12 has become more difficult with different components structure. Today, REWA LAB will separate the iPhone 12 motherboard, demonstrating the separation and recombination operation process. This article will give you a comprehensive analysis of the structure and repair difficulties.
Part 1 Motherboard SeparationRemove the foam on the motherboard with tweezers and then take the sticker around the motherboard off.
Heat the motherboard with Hot Air Gun at 180℃ and remove the plastic part.
Put the motherboard on the Heating Platform. Since the Heating Platform for iPhone 12 has not come out yet, we adopt the universal Heating Platform. Please notice that it requires two people to separate the motherboard here.
Besides, since the middle layer of the iPhone 12 motherboard uses middle-temperature tin soldering which is different from the low-temperature tin adopted in iPhone 11 Pro, the temperature of the heating platform needs to be adjusted to 200℃.
When the temperature reaches 200℃, heat the edge of the motherboard with rotational air (QUICK 861D Hot Air Gun at 320℃). Please be noted that excessive heating may lead to pseudo soldering or falling off of parts. Two rounds of vertical heating are advisable.
Remove the upper layer and lower layer.
Attach the lower layer to the PCB Holder and remove the thermal grease.
To clean the tin on the bonding pad, smear rosin with Soldering Iron at 400℃ and solder-wick. The middle layer of the motherboard uses middle-temperature tin soldering, which makes it harder to clean than the low-temperature tin.
Clean the bonding pad with PCB Cleaner and then handle the upper layer in the same way.
Part 2 Motherboard Recombination
Then we recombine the upper layer and lower layer. Attach the lower layer to the Reballing Platform and put the Reballing Stencil in position.
Apply some middle-temperature Solder Paste and wipe residual Solder Paste with lint-free wipe.
Heat the lower layer with the Heating Platform at 200℃. After the solder ball is formed, turn the power off and cool the motherboard for 5 minutes.
Apply some Paste Flux to the bonding pad evenly. Align the upper layer with the lower layer. After the alignment, keep heating the motherboard at 200℃. To add extra heat, heat along the edge of the motherboard with Hot Air Gun at 320℃.
After cooling the motherboard for 5 minutes, put it back on the phone. Boot up and test. The phone turns on normally.
Part 3 Motherboard Appearance Comparison
The iPhone 12 in our hand is not a U.S. version. As its 5G network frequency band adopts the Sub-6G, there are primarily three antenna connection seats (upper antenna, NFC antenna, and lower antenna).
By contrast, the U.S. version iPhone will feature an extra mmWave antenna while the motherboard will have an additional mmWave antenna connector seat. In addition to differences in the outer look, the layout of the three motherboards is also different. The motherboard of the iPhone 12 is placed on the left while the motherboard of the iPhone 11 and iPhone 11 Pro is placed on the right.
As the new iPhone 12 lineup requires the baseband and chip of 5G to be added to the motherboard, Apple may need to redesign the motherboard and its layout. Next, let’s take a look at the separation of the iPhone 12 sandwich board.
Part 4 Analysis of the motherboard
(1) The upper layer and lower layer of the iPhone 12
As we mentioned in our previous video, the motherboard of the iPhone 12 and iPhone 12 Pro is almost identical in appearance with the double-stacked soldering. The sole difference is that the connecting part of the LiDAR Scanner on the iPhone 12 motherboard has no stuff. Beyond that, we can see two empty parts on the upper layer after separation. The two parts are additionally reserved for the Camera PMU2 and LiDAR PMU on the iPhone 12 Pro motherboard.
(2) A14 Chip
The A14 chip nanometer process, which develops from the A13 chip, goes from 7nm to 5nm. As the first 5-nanometer chip in the industry, A14 Bionic is faster than every other smartphone chip.With A14 Bionic, the CPU, GPU, and machine learning abilities of the iPhone 12 lineup have been improved substantially.
(3) Power Management Chip
According to Bloomberg, Apple is said to face shortages in power chips for iPhone 12. Power management is more important in the iPhone 12 than for its predecessors given additional camera features and 5G capabilities, increasing Apple’s need for these parts.
(4) Card Slot
The SIM card slot of the iPhone 12 series adopts a stand-alone design that is connected via flex cable. In case of any fault related to the card slot during repair, you only need to replace the stand-alone card slot. For comparison, the iPhone 11 card slot is also connected to the motherboard via flex cable, but it is embedded on the motherboard for iPhone 11 Pro series.
(5) Lightning Connector Flex Cable
The lightning connector flex cable of the iPhone 11 Pro integrates Bot Speaker IC, ARC Vibrator IC, Charging IC, and Wireless Charging IC, which increases the possibility of functional failure in the case of water damage or heavy fall. But these ICs are back on the iPhone 12 motherboard, which not only reduces the possibility of lightning connector functional failure but also makes it easier to repair in the case of water damage or heavy fall.
(6) Face ID Parts Comparison
Take the Face ID parts of the iPhone 12 and iPhone 11 Pro to compare. In appearance, the iPhone 12 Face ID front camera module looks much the same as the previous iPhone 11, with some changes to the metal frame and flex cable. The layout of the infrared camera, front camera, and dot projector remains unchanged. It can be seen from the microscope and camera lens that the flood illuminator module at the ear speaker flex cable is different. The lighting area of the iPhone 12 flood illuminator is larger.
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Apr 23, 2021
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