Before we dis-integrate, we first switch off the Mi 4c then we take out the SIM card from the slot. The Mi 4c supports dual SIM card design, dual card dual standby and 2.0 full Netcom, China Unicom, Mobile and Telcom cards. You can choose to use 4G network when necessary.
After we shell the device, we see that mi 4c uses unibody 4c with a full wrap design without any screws. To open the back cover, we slowly pull the bottom of the cover moving on to the top. Even though the design is not meant to quickly open the fuselage, it protects the internal circuit when the phone is dropped.
In fact after we find a little breakthrough at the bottom of the fuselage, we go along the two sides of the body and try to pull it open. There is no glue used to the seal the back cover, the back cover is very much flexible towards maintainance in future.
Like mentioned before, the surface is not exposed of screws, It houses a wrapped up screen assembly through internal snap fastening. The overall design gives a deja vu feeling much like other xiaomi models.
After opening the back cover, the feeling of looking something familiar is a lot there. The location of battery, skin packaging and split up are the same expect the different body shape. The total structural design is totally same a typical Xiaomi.
After opening the back shell one can begin dismantling the screws on the back panel. Once the screws are removed, you must be able to see everything inside. There are total of 14 primary fastening screws, greater than they are in 4i. However, the integration of the body and sturdiness did not change.
After all the screws are removed, we will begin removing the backplane. As long as we find a breakthrough, the back is still very easy to be dismantled.
After we removed the back, we first need to disconnect the battery cable, cutting off power to the motherboard. Also we do the same for other cables.
Only after disconnecting the cable, we can remove the motherboard. On board there are a few silver screws, we will one by one unscrew them. Screws found on the motherboard and backplane are not the same. Backplane screws are black and screws on motherboard are relatively small and silver in color.
After we remove these screws on the left and the RF cable connected to the motherboard. To remove the RF line we must be careful about not pulling this line up directly. Make use of forceps to disconnect and put it down.
Mi 4c has dual card dual standay, Netcom 2.0 and Network to meet all the needs of users in terms of telcommunication connectivity. The device is also added with “high speed rail mode” to optimize the signal received by the phone while moving on high speed trains. The feature cancells the errors caused by Doppler effect due to signal frequency shift. It ultimately locsk the best signal and connects with the base station. The failure rate by this method is reduced by 90%.
When all fixed board positions are loose, we can take down the board, including its 13 million pixel primary camera, the main supplier for Sony and Samsung, to support phase focusing.
Mi 4c for the first time comes with a black PCB board which uses thick materials. The different elements are densely distributed on the board, such as mini SIM card slot, flash memory, Qualcomm Xialong 808 processor, memory and other components.
After unit is completely disassembled, we found a small piece of element that embeds processor and memory in a metal shield. This type of configuration is rarely seen in any other device. The aluminum-magnesium alloy frame is specially reserved for the two chip corresponding to the shape of the groove, and the opposite part of the processor. There is also a layer of silica films, for cooling the processor.
Overall the design of the motherboard of Mi phones have always liked using primary and secondary + flexible printed circuit board connected to the interior design.
This design used for the technology is relatively developed, simple, easy to mass produce and cost of maintainance is low.
Now we start to disintegrate the Mi 4c battery. Like iPhones there is an alternative for dismantling the tape on the battery. Tear and tug it hard to remove the battery which is not difficult to do. The battery of mi 4c uses a square design and this shape facilitates easy accomodation of large capacity battery of 3080mAh. With moderat usage, battery can give backup for 24 hours.
Under the battery there is a small board above RF line. Again we have a larg board that is disconnected and you can take the RF line down.
Next we look at the big board on the upper part of the handset. In Mi 4c the light sensor and the receiver are integrated in the same module. It is firmly placed inside the card slot and we have to remove it by hand.
Next we have to pull the small pads. We have to remove the small items that are easily overlooked and lost. We need to give more attention on the dis-integration process.
The entire dismantling process is over, we now look at the mi 4c parts. The components we removed are two upper and lower back, the back cover, a 3080mAh battery, dual SIM card slots, an RF line, a pad , an earpiece sensor, 13 million pixel camera, 500-megapixel front camera, 14 black screws, 2 silver screws, a motherboard and screen assembly.
4c uses a total of two sets of screws. one set to fix the motherboard cover, black (total 14), another set to fix the main sub-plate, silver (total 4). This makes a total of 18 screws, 4 more than the predecessor 4i. This results into nothing much significant, it integrates the board firmly with small improvement.
Overall, Mi 4c is well built like a phone AK47. It has a simple structure, easy to replace parts, and its maintenance is very easy. This can be used in harsh environments and yet it provides an outstanding feel from the outside.
The recovery of the phone is quite difficult but not impossible. There are two places that could consume time, one reset of printed circuit board, second the installation of motherboard. The problem is mainly with aligning thier position properly in place. It might take more patience and time.