Can a WiFi device disconnect a router from the internet?

First off - networking is an area I have the least knowledge of so just so you know, I have no idea ;)

My questions is simple - is it in ANY way technically possible that a device trying to connect to a router via WiFi can cause the router to lose internet connection?

I'm asking because my internet is/was always very stable. I can't remember it ever disconnecting just like that and recently something changed - I would suddenly lose connectivity. I mean - the diode that shows up whenever the router connects to the internet would just turn off and I have to reboot the router to make it reconnect.

Now, there is a specific event that marks the beginning of this issue - the use of a Smart TV. The TV is connected wirelessly to the internet via my router and I have some reasons to believe that it may (?) be involved in this because today, knowing that no other device is using WiFi, I saw the WiFi diode blink a lot like crazy for a moment and then the router disconnected from the internet. The other 2 times when this happened earlier also happen at the time that internet was used through the TV.

This makes 3 disconnections within just a couple of days since this TV is in use and I have no idea if it's causing this or (hence my question) if it's even technically possible that somehow the attempt of connecting via WiFi through a router can cause the router to disconnect from the net. Is it?

Time for troubleshooting. Firstly, we need as much information as possible. Do you have a combination modem/router/wap, or 2 separate units(modem, router/wap)? What time of day do these things happen? Can you cause the problem to repeat itself by making sure the internet is stable, then activating the TV? Also, try disabling the wifi on the TV to see if the problem goes away (smart TVs are creepy anyway[LG, according to the tek]) When the problem next occurs, access your router configuration page, and see if anything on the status readout seems out of place and look for any logs it may have. 

If you need any help with any of those steps feel free to ask 

I believe its 'kinda' possible the TV could do this, but highly unlikely. It would have to like.. DDOS you from inside or... flood DNS packets or something crazy. 

or your modem/router/wap can't handle it, and fills its memory and crashes or something stupid like that. 

Hopefully it's one of those problems that happens three times and never again ;) 

I have one device which is a modem and a router, it's a TP-LINK TD-W8951ND, I connect my phone line into it and then I have 3 devices connected wired (PC, PS3, A/V Receiver) and theoretically 5 WiFi devices (incl. the TV). Theoretically because at no point in time are all of them on. Normally it's either just the TV and an Android tablet + 1 device sometimes (iPod).

As for reproducing this issue - that's the problem, I can't reliably reproduce this. I have this TV since a week and once I got disconnected twice in the same day (the day I've got it) and the next disconnect was yesterday, but in between, this TV was used a lot - YouTube vids were streamed, sites were visited etc. and it worked fine, nothing got disconnected.

As for logs - well... that was a facepalm moment for me yesterday when I saw it disconnect, rebooted the router and THEN realized I should have checked its logs. I'll definitely do this next time it happens.

I also hope it was just a coincidence that I got disconnected a few times lately and it has nothing to to with the TV, but still - my curiosity kicked in and I saw a pattern (I buy a TV -> disconnects begin and happen when internet is accessed through the TV) and then I just HAD to know if it's possible that the TV or any WiFi device can do something like this ;)

I'll keep you posted. As I've said, if it happens again, first thing I'll do before rebooting it is to check the logs from the config page.

It happened again! But in a way, that's good news because now I know for sure that it happened when the TV was off. I mean, in "idle" not like hardware off with the switch in the back, but still - off.

Anyway, this time I didn't reboot the router, I waited and let it reconnect by itself and checked the logs in the 192.168.1.1 page (how do you call it - admin panel?). Here's the log:

12/3/2014 18:16:40> Call drop because echo reply not received in time

12/3/2014 18:16:40> SNMP TRAP 2: link down

12/3/2014 18:19:15> MPOA Link Down

12/3/2014 18:19:15> SNMP TRAP 2: link down

12/3/2014 18:19:15> SNMP TRAP 2: link down

12/3/2014 18:19:15> SNMP TRAP 2: link down

12/3/2014 18:19:15> SNMP TRAP 2: link down

12/3/2014 18:19:15> SNMP TRAP 2: link down

12/3/2014 18:19:15> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:19:16> Last errorlog repeat 2 Times

12/3/2014 18:19:16> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:19:18> Last errorlog repeat 8 Times

12/3/2014 18:19:21> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:19:22> Last errorlog repeat 9 Times

12/3/2014 18:19:28> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:19:29> Last errorlog repeat 2 Times

12/3/2014 18:19:31> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:19:32> Last errorlog repeat 1 Times

12/3/2014 18:19:33> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:19:51> Last errorlog repeat 20 Times

12/3/2014 18:20:15> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:20:17> Last errorlog repeat 1 Times

12/3/2014 18:20:18> netMakeChannDial: err=-3001 rn_p=80544b08

12/3/2014 18:20:29> Last errorlog repeat 3 Times

12/3/2014 18:20:29> MPOA Link Up

12/3/2014 18:20:29> Quick bridge not allow multi-channel

12/3/2014 18:20:29> bridge only stop

12/3/2014 18:20:29> SNMP TRAP 3: link up

12/3/2014 18:20:29> Quick bridge not allow multi-channel

12/3/2014 18:20:29> bridge only stop

12/3/2014 18:20:29> SNMP TRAP 3: link up

12/3/2014 18:20:29> Quick bridge not allow multi-channel

12/3/2014 18:20:29> bridge only stop

12/3/2014 18:20:29> SNMP TRAP 3: link up

12/3/2014 18:20:29> Quick bridge not allow multi-channel

12/3/2014 18:20:29> bridge only stop

12/3/2014 18:20:29> SNMP TRAP 3: link up

12/3/2014 18:20:29> Quick bridge not allow multi-channel

12/3/2014 18:20:29> bridge only stop

12/3/2014 18:20:29> SNMP TRAP 3: link up

12/3/2014 18:20:44> ppp_ready: ch:80563688, iface:804e4fa8

12/3/2014 18:20:44> SNMP TRAP 3: link up

12/3/2014 18:20:44> Accept() fail

12/3/2014 18:20:44> Accept() fail

12/3/2014 18:21:18> dynDNSOrgLogin:Error = -8, retCode

So please let me know if any of the above rings a bell, if any of these errors clarifies a specific reason for the disconnect. I'll appreciate any suggestions, if you want to know any other settings on my router - let me know, I can post anything except the admin password of course ;-)

Sorry I've been away for so long, and it doens't look like anyone else has popped in to help you, how'd it go?

Turns out it was random coincidence that it disconnected a few times and doesn't matter anymore as in the next days I'm switching my ISP from one who tried to push 20 Mbps over decades old copper to one that offers me 150 Mbps over fiber :)

Q1: Is your wifi router connected to internet through wifi?
Q1.5: If its not a wifi, is it coax cable?

1: No
2. The old one was connected via phone line, the new one is connected via a "concentric cable".

But again, it's no longer an issue, it must have been some glitch from my old ISP, it no longer happens anymore :)