If the Xiaomi tablet is released late, in order to bring users a redefined tablet usage, it is obviously not realistic. Because it does not bring us much innovation. But the banner of "doing the best Android tablet" that it played also gave us some thoughts. Why is this tablet so mad? How to achieve the "best" price of 1,500 yuan. So today, let's take a look at this late Xiaomi tablet disassembly, maybe we can find some answers.
Before I start dismantling, please allow me to briefly introduce this tablet. Xiaomi Company released the first flat product in May this year - Xiaomi Tablet. At this time, the sales of the iPad fell, the price war of the Android tablet camp became more and more intense, and the Windows tablet camp was in a difficult time of growing up in the gap between the two. Xiaomi chose to launch its own tablet products at this time, and it must have its own intentions.
In my opinion, Xiaomi is considered in two aspects. First of all, at the software level, since the tablet and the mobile phone are completely different ways of use, for a manufacturer who has not done a tablet, it is as outstanding as the MIUI mobile phone system. Tablet PCs are by no means an easy task; on the hardware level, Xiaomi wants to maintain a high price/performance ratio of products, which inevitably requires “sufficient materialâ€. We have seen that Xiaomi uses a fully-fitted retina screen with the most powerful NVIDIA K1 processor chip and 802.11 AC dual-band antenna. It is true that these configurations are excellent in the tablet.
Today, we don't talk about the good and bad of Xiaomi Tablet. We just want to know what the K1 chip looks like, then please open the millet tablet with me to explore this "best Android tablet".
The disassemble of the one-piece body generally starts from the frame
The millet flat plate adopts an integrated body design, and a fixed screw can not be seen through the whole body. Therefore, for this type of flat plate, the common disassembling method is to start from the gap between the screen and the frame.
Knock the border slit a little bit by a crowbar
When the crowbar penetrates into the gap between the screen and the frame, the inside of the fuselage makes a crisp sound. We continue to expand the gap. This sound will appear every time a node is reached. We conclude that this is the sound of the buckle, the back shell of the machine and The fuselage is fixed by internal snaps.
Close-up after the back shell is separated
When enough buckles are separated from the fuselage, we can remove the back shell. At this point, it can be seen that the structure on the fuselage is very compact, and the main board part is tightly covered by a black plastic cover, which is fixed by 12 screws. If the user wants a warranty, we do not recommend that the user disassemble the machine, because there are several screws on the cover with a warranty sticker. If the sticker is damaged, the machine will not be warranted.
The rubber at the end of the button can be waterproof
On the back of the fuselage, the hard position with the rear camera is a camera fixed original. The position corresponding to the main board is a graphite thermal paste for dispersing the heat of the main board. The button on the back shell is made of rubber to provide a certain waterproof effect. The design on this detail is quite intimate.
Battery disassembly sound chamber separation
The millet slab adopts a one-piece body, and the whole machine does not see a screw, so it has a simple aesthetic. The back shell of the machine is designed with an inner snap, and we can open the back shell simply by inserting a thin rod into the frame around the screen. When opened, you can see a very compact internal construction. Although the motherboard is protected by a 12-screw black cover, it can be easily removed with a Phillips screwdriver, so let's do this!
Remove the black cover, the motherboard of the machine will come into view, guess where K1 is?
The 12 screws on the black cover are removed, and the cover can be easily peeled off. Most of the inside of the cover is covered with a graphite heat sink, and the 3.5mm headphone jack is also fixed on the cover to ensure repeated connection of the earphones. Do not shift or damage the interface. The middle metal piece is the link fuselage antenna to enhance the signal strength. At this point, the motherboard has been shown in front of us, the core components are almost protected by metal shields.
After removing the speaker, the data line interface at the bottom is exposed
According to the top-down dismantling principle, we don't worry about removing the motherboard, but instead turn our attention to the speaker below the fuselage. It is fixed by four screws. After removing the screws, the speaker can be taken out. It consists of two parts. The sound of this speaker is very good. Not only the volume is loud, but also the sound is round and delicate, although it is not visible from the outside. Its source, but from the sound quality can be concluded that it is a product produced by a large and experienced factory.
The battery model is BM60, from LG Electronics, 6520mAH capacity, voltage 4.35V, 26.46Wh
Removing the battery is perhaps the easiest part of the entire disassembly process. We only need to separate the battery from the power cable of the motherboard, then hold the straps on both sides of the battery, and use a little force to easily remove the battery. This battery, model BM60, comes from LG Electronics, 6520mAH capacity, voltage 4.35V, 25.46Wh.
Disconnect the cable separation board
The battery capacity of the iPad mini 2 is 23.4Wh, while the battery capacity of the Xiaomi tablet is 25.46Wh, which is slightly higher than the capacity of the iPad mini 2. Therefore, the battery life of the Xiaomi tablet is still very good, even with a resolution of 2048*1536. The 7.9-inch screen, watching the video also claimed to reach 16 hours. After seeing the battery, we will return the line of sight back to the motherboard of the millet tablet. This time we really have to take it down.
Disconnect the cable and separate the rear camera
Stripping display cable
Stripping data lines, speaker cables
Stripping volume button, power button cable
Strip the vibration motor and the audio interface cable.
Stripping touch screen controller cable
In order to remove the motherboard, we need to disconnect all the cables on the upper link, and then unscrew the two screws of the fixed motherboard to remove the motherboard. The order of our work is to separate the rear camera first, and then open the screen cable, the data cable, the volume button cable, the touch screen cable, the front camera cable and the two screws that fix the motherboard.
Front view of the motherboard
Compared to mobile phones, the tablet has more internal space, so the circuit design of the motherboard is also simpler. We saw that the important chips of Xiaomi Tablet are designed on the front of the motherboard. The core chip and the original are also protected by metal shields to prevent electromagnetic interference. The chip-dense area on the back of the motherboard also has a graphite thermal paste for heat dissipation.
Remove the front camera after removing the motherboard
The left is an 800W pixel back-illuminated camera produced by Sony, and the right is a 500W pixel F2.0 aperture front camera produced by SUNNY.
The machine uses Sony's rear 800W pixel camera, the imaging resolution is higher than the iPad mini 2 with only 500W pixels, but the performance of white balance is not as good as the iPad. In the front camera, the millet tablet uses a 500W pixel camera with F2.0 aperture, so whether it is self-timer or video chat, this configuration is enough.
Exploring chip violence dismantling
If the above three pages of text readers have finished reading, then I think perhaps the reader is now ridiculing that the author is a title party, because there is no mention of any mistakes in the front, let alone violent dismantling. However, on this page, I will explain the reasons for my mistakes to everyone, I hope everyone will be patient.
In addition to the Xiaomi tablet, the NVIDIA K1 chip that can be seen on the market is the NVIDIA's own Shield tablet. However, because the Shield tablet is not listed in China, the Xiaomi tablet is the only K1 product we can get close to. I personally hope that I can see what this chip looks like, but in front of it is a metal shield to block the position of the K1, only the largest one uses a snap design, the rest of the shield is used Industrial welding is up.
Disassemble the only metal shield with a snap-on design
Toshiba thgbmbg7d2kbail 16GB eMMC flash chip
Unless I can find the K1 chip under the snap-on shield, I can only violently open the remaining shields. When I opened the first shield, I saw two large and one small chips. The smaller one was from Toshiba's flash memory chip, the model was thgbmbg7d2kbail. The flash memory was manufactured using Toshiba's second-generation 19nm process. e.MMC 5.0 standard, mass production at the end of 2013. The chip adopts FBGA packaging technology, so that the ratio of chip area to package area exceeds 1:1.14, which not only can bring better heat dissipation effect, but also reduce the chip size, which is a new product with outstanding performance.
Mysterious SK Hynix H9CKNNNBKTMT chip
The larger chip surface is printed with SK hynix, so it is concluded that this chip is from SK hynix, but through the surface model H9CKNNBKTMT, but can not find the relevant information, it can be concluded that it should be the machine's RAM. (The mistake is here)
Violent dismantling of the second metal shield
Since K1 was not found, I had to find a way to open another metal shield to find the trace of K1. First I intend to open the metal shield near the middle. I originally wanted to use a soft air gun and a soldering iron to make the metal shield welded on the PCB unsold, but the method did not work. The heat gun and the soldering iron did not work until 300 degrees. If the temperature is higher, it is bound to be Will burn the chip, so I have to give up. Had to use the oldest and rude practice, use a thin screwdriver to force open the shield. As for the process, I will not elaborate. A lyric can express my heart: The picture is too "beautiful" and I dare not look at it.
Texas Instruments T65913B3BE power management chip mainly provides power management for K1
After opening the first welded metal shield, we can see a model of the T65913B3BE power management chip produced by Texas Instruments. I suspect that the management chip will mainly manage the power of the Tegra K1 core. However, there is almost no record on the domestic website for this chip, and even on the official website of Texas Instruments, the chip is not found. The author finally found a simple record of the chip in foreign media.
German instrument BQ24192 power management chip, mainly manages battery charge and discharge
Next to the T65913B3BE power management chip, the author also noticed a chip also from Texas Instruments, model BQ24192, which is mainly responsible for power supply and discharge management, and can bring faster charging speed for Xiaomi tablet.
Continued exploration of violence continues to explore K1
The second metal shield that was opened by the power of the smashing of the tiger did not find the K1 chip that the author wanted to find, so I did not end the second, and continued to dismantle the third metal shield.
Next, the author began to dismantle the third metal shield in the middle of the PCB. Here, I would like to ask the author to say: These shields are for industrial welding. Compared with household solder, these industrial solders have higher melting points and strength. High, so gentle use of hot air guns and soldering irons does not work for them, but the consequences of violent dismantling are well known. I will not repeat them.
The third shield contains two NXP TFA9890 speaker driver chips, Realtek ALC5671 audio decoder chip
Unexpectedly, the smallest metal shield has the largest number of chips inside, including two NXP TFA9890 speaker op amp chips, which can provide speakers with more powerful low frequencies than other flat panels without breaking sound. This is not possible with mobile phones because of power limitations. The Realtek ALC5671 audio decoder chip is a mid-range product in the ALC product line. There is also a chip called AIF BCG. At present, I have not found any relevant information. If the netizens know, please leave a message to me. thank.
Broadcom BCM4354 wireless chip
Next, let's disassemble the last shield. This shield is not small. After disassembling, I only saw a chip with a reflective surface, which really raised the author's interest. This chip is difficult to see with the naked eye, but under the macro lens, the text on the chip is still very Well recognized - Broadcom BCM4354 wireless integration module. As a high-end product of Broadcom, the chip is mainly used in high-end mobile phones. It has dual-transmitting dual-receiver 2x2 MIMO, supports 5G Wi-Fi 802.11ac, and integrates Bluetooth 4.1LE and FM radio functions. It is said to have a maximum downlink speed of 867 Mbps (channel bandwidth of 80 MHz), which is twice as much as 433 Mbps for the original single transmission single reception. It seems that it is not in the table.
The last step is suspense
When all the metal shields were removed, my incomprehensibility was not increased, because I still didn't know exactly where the Tegra K1 chip was.
All the shields have been removed, but still do not see the K1 logo
In order to figure out the specific location of K1, I finally found the answer to the question. It turns out that K1 is under the shield of the best-disconnected snap-on design - the largest chip on the motherboard. The SK hynix written on this chip is indeed the 2GB Ram of the machine, so the most reasonable explanation is that the NVIDIA Tegra K1 chip and the Hynix 2GB Ram are packaged in a POP technology stack. The advantage of this design is to save space, close the distance between the memory and the processor, and improve the response speed. But when the processor temperature is too high, will Ram be affected as well?
Tegra K1 processor with 4+1 processing core and 192 Kepler-based GPUs
The reason why I pay so much attention to the Tegra K1 chip is because this chip has enough powerful performance. It uses the same Kepler-based GPU as the computer graphics card, which replaces 192 display cores, which can bring a dramatic graphics processing capability compared to the previous generation, making it compatible with the Unreal Four game engine. This brings an unprecedented mobile platform gaming experience.
In the processor part, NVIDIA also uses 4+1 core design for K1, four of which adopt Cortex A15 architecture, the main frequency reaches 2.2Ghz, and the other companion core only works when the machine is lightly used. Reduce the power consumption of the machine. But there is a problem that arises spontaneously. How can we use such a powerful configuration? It's still hard to find a game designed specifically for the K1 system, because after all, the Android platform is a big circle, game developers need to take into account the interests of the overall situation, and may not only spend more energy for the niche group using K1. So I think that if you want to experience the best performance on the millet tablet, I am afraid it will take a short time.
Disassembly summary:
The difficulty of dismantling the millet slab is 4 points, and the 10 points are the most difficult.
Although the tablet has been released late, it has created many first in the tablet industry, such as the first NVIDIA K1 processor and the first to run the tablet MIUI system. But Xiaomi’s claim to be the best Android tablet is not as simple as it might seem. Although the hardware can indeed give people a hard-to-reject gimmick, the design and details of the product are also in place.
But returning to the value of the product itself, we have found some problems, such as the strength of K1 is difficult to play; and the stacked package technology will not affect the normal operation of Ram because of the high power consumption and high heat of K1; 802.11AC Despite the advanced technology, only the route that satisfies the technology can be realized. However, most of the WiFi environments do not support this technology. With so many advanced technologies, it is useless. Is it not just consumers who want headaches?
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