Cisco EA6700 / Linksys AC1750 Router

Cisco EA6700
Cisco EA6700

Since the boat was still running it’s internal network on 10/100M speeds, an upgrade was decided on, the internal WiFi signal strength was also pretty poor further than a few feet from the NOC.

The new router is a Cisco/Linksys AC1750 model, with gigabit networking, and full 802.11ac 2.4/5GHz Wireless. This router also has a built in media server, print server, USB3 & USB2.

PCB Overview
PCB Overview

Teardown time! Here’s the router with the cover removed. Most of the fun stuff is hidden under the shields, but these aren’t fully soldered down & the covers are removable. The 6 antennas can be seen spaced around the edge of the housing, the main CPU is under the large heatsink upper centre. The radio power amplifier stages are underneath the shields, while the main RF transceivers are just outside the shields.

2.4GHz Transceiver
2.4GHz Transceiver

Wireless N is provided by a Broadcom BCM4331, this provides full dual-band 3×3 802.11n support. Being 3×3 it is actually 3 separate transceivers in a single package, to get much higher throughput rates of 600Mbit/s.

5GHz Transceiver
5GHz Transceiver

Wireless AC is provided by it’s sister IC, the BCM4360, with throughput speeds of 1.3Gbit/s. Both of these transceiver ICs connect back to the main CPU via PCI Express.

5GHz Power Amplifiers
5GHz Power Amplifiers

To get increased range, there are a trio of Skyworks SE5003L +23dBm 5GHz power amplifier ICs under the shield, along with the TX/RX switching & antenna matching networks. Heatsinking for these is provided by a sink screwed to the bottom side of the PCB. The outputs to the antennas can be seen at the top of the image.

2.4GHz Power Amplifiers
2.4GHz Power Amplifiers

The 2.4GHz section is fitted with a trio of Skyworks SE2605L +23dBm 2.4GHz power amplifiers, with a similar heatsink arrangement under the board. Unlike the 5GHz section, the 2.4GHz antenna feeds are soldered to the PCB here instead of using connectors.

Main CPU
Main CPU

The main CPU is a BCM4708 Communications Processor from Broadcom, as for the other Broadcom chips in this router, very little information is available unless under NDA, but I do know it’s a dual core ARM Cortex A9 running at 1GHz, with built in 5-port gigabit ethernet switch.

CPU RAM
CPU RAM

Working RAM for the processor is a Hynix H5TQ2G63DFA 256MB part.

More to come on the installation of the new networking, with it’s associated 4G mobile gateway connection system.

73s for now!

2 thoughts on “Cisco EA6700 / Linksys AC1750 Router

  1. Chris says:

    Do you happen to know the sizes of the capacitors used on this?

    I got one used and in opening it up, a screwdriver head fell out and sheered off one of the tiny chip capacitors and they have no markings.

    If not, I can find a multimeter that has capacitance function.

    Thanks

    Reply
    1. The Engineer says:

      Hi Chris,

      Unfortunately not, and you’d need to be more specific! Depending on where the cap is in the circuit, it may not matter than one is missing. However if it’s in a more critical area, the dielectric could be important too, which a capacitance tester wouldn’t tell you!

      Cheers

      Reply

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