Hi all,

Apologies for my brain dump but I am at my wits end with my network and I do not know what to try next.

My ISP is Brsk providing a 500Mbps upload/download. I have their router in passthrough/modem mode and my Archer C5400X is plugged into that.
My network is very unstable, I loose wired and wireless connection several times a day. I cannot find any uptime on either the Brsk or Archer devices so I can only assume they are not rebooting.

My first question, how can I narrow down which device is causing the drop-outs? 

I have a TP-Link Powerline extender plugged into my Archer. The other end is in my garage which is on the same electric circuit as the house.

I have to keep rebooting both of these powerlines to get them to reconnect. They have the latest firmware and I have factory reset them and repaired them several times but after a few days they will drop out again. Rebooting alsways reconnects them temporarily.

Second question, how can I make these powerlines more reliable?

And lastly. I am looking to overhaul my network but I am reluctant to replace the Archer C5400X as it cost me a lot of money and when it works, it works well. I have an Archer C80 in access point mode also connected to it to extend my wired and wireless connection into the loft extension.

What would be the best way to cover dead spots around the house without but a whole new Mesh system? Any suggestions are welcome!