Repair LAN ports on router

[Doppler]

Hello,

I'm not willing to give up on this device. The problem started after power outage. Router works fine (sort of). It boots. I can see its wireless networks. I connected it to serial port and I can see booting process.

LAN ports are problem!! Their LED's are always on and I cannot connect PC to it.

What part of hardware I need to inspect to solve my problem? PLS help. I'm willing to provide any information you need.   

[retiredcaps]

It helps if you provide the make and model number.  After that, see if there are any instructions on the Internet to do a software reset to default settings or a way to upload/reflash firmware.

[MAS3]

The sticker on the yellow plastic RJ45 array cover tells it is an Archer C7, and Google tells that that would be a TP-Link product.


In the centre of the picture you can see a smaller square chip, from which lots of leads lead to the LAN transformers G4812CQ, which then go to the RJ 45 connectors.
It will be hard to repair, and i have no doubt that part need to have firmware installed for it to work in that product.
There could also be a problem with the power supply to that chip.
I'd say that is the part below that chip and at its right, with the 3 capacitors in a row on that picture, but that might as well be the supply to the USB ports next to that.

[Doppler]

The sticker on the yellow plastic RJ45 array cover tells it is an Archer C7, and Google tells that that would be a TP-Link product.

You are right it is Archer C7 AC1750 TP-Link router

Specifications:

UPC: 845973070601 (UPC DB, On eBay)
Power: 12 VDC, 2.5 A
CPU1: Qualcomm Atheros QCA9558 (720 MHz)
FLA1: 16 MiB (Winbond W25Q128FV)
RAM1: 128 MiB (Winbond W9751G6KB-25 x 2)
Serial: yes, internal, 4-pin header, 3.3V TTL

Router works, I can see its wireless networks. I connected routers serial interface, and with Hypertherminal I can see boot process. There is nothing wrong with processor or firmware, I'm sure. Problem are LAN ports. How can I inspect them?

There could also be a problem with the power supply to that chip.

How can I check this?

[Rasz]

gigabit switch chip is blown

There could also be a problem with the power supply to that chip.

How can I check this?

Im affraid asking this question indicates this repair is beyond your abilities
you need hot air to swap http://www.ebay.com/itm/1x-AR8327-BL1A-AR8327-B-AR8327-BL-AR8327-BL1-AR8327-BLIA-AR8327-BL1A-QFN148-IC-/400970910341?hash=item5d5bba8a85

[Doppler]

gigabit switch chip is blown

This chip is very hot.

I have hot air rework station, I can replace it... I need to be sure that power supply to that chip is ok! 

[OldSchoolTechCorner]

gigabit switch chip is blown

This chip is very hot.

I have hot air rework station, I can replace it... I need to be sure that power supply to that chip is ok!

Make sure you pre-heat the board for a few minutes, or use a pre-heater, so you don't warp the board, when you use the hot air rework station.  It more likely the AR8327-BL1A1 gigabit chip.