Today I found a router from my cousin's trash can. The antenna was broken. Next to it was a new Asus router box, a big one. I couldn't see the model clearly, but there were power cords from various countries in the box. The owner must have thrown away the old one when he got the new one. I gave the power cord to my cousin and I disassembled the old router.
The router must be old, and the plastic on the back cover is a bit aged, probably because it is close to the window and exposed to the sun.
Let’s first look at the appearance. The model is ASUS AC1900. Let’s take a quick look at the data on the label at the back. The power supply is DC 19V 1.75A, made in China, and there are 4 buttons, abcd. The A button can set up the WiFi link with other wireless devices, the B button is the reset button, the C button is the WiFi switch, and the D button is the LED switch.
There are pictures at the end, which is simple and easy to understand.
Then there are some various standards. I don't know if the ID is the production date of 2013.
Let's look at the top again. There are three antennas in total. They are not the kind of integrated ones, but can be twisted off. The heat dissipation area at the back is more seriously aged.
Let's look at the interface. There is a reset button and a power button on the left. The power input is 19v on the bottom. Remember that 9-12v is enough for ordinary routers. To the right is a 2.0 interface and a 3.0 interface, which can be used to connect to the hard disk. The user end can directly read the hard disk information, similar to NAS. To the right is a network cable interface. The LED switch in the middle may turn on the light of the ASUS acrylic at the bottom.
There are only four interfaces on the right, which are used to connect to the user end.
The front is relatively simple, with the logo in the upper right corner, and the model number 1900, which supports 802.11ac. There are 10 indicator lights at the bottom to show the current status.
No need for a screwdriver, absolutely no need, you can just remove it with your bare hands. Slowly pry it down, you can see that the screws are also seriously aged, so you can just take them off.
The first thing you see is a large aluminum alloy heat sink.
The two buttons on the side are WPS and WiFi switch.
The back is almost completely broken, and the whole board is exposed. The base is still not removed.
The base can also be easily removed, and as expected, three LEDs directly illuminate the transparent ASUS logo.
There is nothing on the front panel except a transparent piece with an indicator light.
Let's study the motherboard again. This is the back side, and the chip is also on the back side. Most of the components are on the back side.
There are relatively few components on the front. The dotted circle should be a shielding cover, which is missing a chip and is marked with U11/U12. There are also several resistors missing at the bottom. U8 on the left is also missing. Is there a high-end version? The LED indicators at the bottom are all black. The three on the right should be always on, the power 2.4/5G and the fifth Internet from the left. Under normal circumstances, these are always on or flashing. So the others are rarely used. It looks normal. There are no components at the bottom of the heat sink after disassembly. It only assists in the heat dissipation of the chip on the back. The shielding cover on the top is fixed by three screws to reduce the mutual interference between the antenna and the motherboard.
Let’s first look at the first chip, U13, the brand is Spansion Semiconductor, the company was acquired by Cypress CYPRESS in 2014, and Cypress was acquired by Infineon in 2019, so the chip silkscreen S34ML01G100TF100 you are looking at now, the data will show Infineon.
The chip is an embedded system memory and a high-reliability SLC NAND flash memory particle.
Pinout diagram for this flash memory.
This U17 is a 1.5A adjustable/fixed low-dropout linear regulator, brand UTC Youshun.
U1 silkscreen IT7663M is a high-efficiency synchronous rectification step-down DC converter.
U2 is also an IT7663M.
Interfaces on the back: an HN18101CG network transformer, USB3.0 and USB2.0 interfaces, power supply and switch.
The three LEDs in the middle, U3 and U4, are all IT7663M, while U5 is IT7803M, which are all high-efficiency low-voltage DC converters.
There are two transformers for the network port, 1434 and 1444, and a U7 next to them.
Remove the heat sink, revealing two shielding covers, and there is a heat sink at the corresponding position of the chip above the shielding cover, which is more conducive to heat dissipation.
Remove the shielding cover on the right side, and there are two chips inside: U9 and U10.
The U10 uses a Samsung K4B2G1646Q, which is a 2Gb DDR3L flash memory chip.
U9 is a Broadcom BROADCOM, silkscreen BCM4708, a network acceleration hardware communication processor. The center of the device is a high-performance 1GHz ARM CortexTM -A9 dual-core, with a 32kb four-way set-associative instruction cache and a 128-entry translation lookaside buffer (TLB). The enhanced CPU memory subsystem architecture provides higher system performance. The device uses 40 nanometer technology.
After removing the shielding cover on the left, we can see two chips U24 and 23. Both are Broadcom's BCM4360. This chip is a 5G WiFi 800 2.11ac Gigabit transceiver. The entire network part of the router uses Broadcom's solution. The two chips manage 2.5G and 5G WiFi respectively.
U23, PHY rate performance is more than 3 times that of three-stream 802.11n devices Dual-band operation is compatible with 802.11n networks that are not recommended for new designs. 80 MHz bandwidth is 2 times wider than current 802.11n. 256-QAM is a higher modulation scheme that improves data transmission efficiency 802.11ac-compliant transmit and receive beamforming to extend the coverage of 802.11ac, which is not recommended for new design devices. Low-density parity check (LDPC) code can increase the rate within a certain range PCI Express 2.0 host interface Enhanced Bluetooth coexistence interface supports seamless BT+5G WiFi operation solution
In the RF part, the 5023L is a 5GHz power amplifier that provides high linear power for wireless LAN applications. The SE5023L provides a high degree of integration for simplified design, shortens time to market, and improves the production yield of application boards. The device integrates all matching components, temperature compensation, load-insensitive power detectors, has a 15dB dynamic range, and a 3.8GHz otch filter. For wireless LAN applications, the device meets the requirements of IEEE802.11ac and 802.11n, and provides approximately 24dBm 802.1lac output power or 26dBm 802.11n output power at 5V.
The 2.5G part is almost the same as the 5G part, and the right part is the power supply part.
This router model has a 1900Mbps speed (600Mbps on the 2.4GHz band, 1300Mbps on the 5GHz band)
Processor, BCM4708,
The memory is 256M flash memory and 2GB memory.
Network interface: 1 Gigabit WAN port, 4 LAN Gigabit ports.
Antenna: 3 5dBi external antennas.
It was launched on June 4, 2013, with an initial price of about $200.
It is still on sale on Taobao, the price is less than 200 yuan, and it is around 100 yuan in the seafood market.
Ok, this is the end of the disassembly. If there is any incomplete analysis, please feel free to give me your suggestions.
Due to personal reasons, the disassembled motherboard will not be reused. It will be thrown into the trash can after being kept for a few days.
This content is originally created by EEWORLD forum user Zhang Xinyun. If you want to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source
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