M4 Satellite flashing Red after every 15-20 mins disconnecting
My M4 satellite is flashing red and losing connection every 10-20mins.
Steps I have tried:
- Power cycled both main and satellite
- Reset both main and satellite
- Kept both main and satellite NEXT to each other to test whether there are interference issues.
The connections were working fine, (purchased this duo-pack almost 3 years ago), I live in a concrete duplex home, and all this time my main was on the top floor while my satellite was at the bottom, because my ONU device was on the top floor originally.
So yesterday, I finally shifted my ONU device to the bottom floor, to keep my MAIN there and I moved my satellite to the top floor, and this issue started and the wifi internet SPEED on the satellite is VERY poor.
Would really like some advice, I do not wish to spend so much money on purchasing another device.
@David-TP @Marvin_S
I have found the error and it was HUMAN ERROR!
So in the midst of the shifting of the decos from top to bottom, at one point I cannot recall why, I decided to test out one of my very old 840-N router.
And then I left the power adapter there on the power strip. Because I was using a portable mini-ips to power my satellite router upstairs, I completely forgot what the original power adapter of the deco looked like.
So today, I went to the store and purchased a brand new Archer C6 to try one last time to figure out what was the issue with the main M4. 
Right after I opened the box, i unplugged the power adapter to the M4 and saw that it was the OLD 840-N adapter connected to it (9V-0.6A)=5.4Watts
Deco power adapter is 12V-1.5A=18 Watts!!!
No wonder it was working okay under normal load, but anytime it tried to run under 100% load, because it was UNDERPOWERED, it was auto-restarting. 
So ISSUE RESOLVED. Thanks All!
Marvin,
So i have swapped the downstairs main router with the upstairs satellite.
But everytime I try to run a speedtest, the new staellite turns flashing red and disconnects. And IF there is a sustained connection the up and down speed is very poor.
It should be 100mps both ways. See attached.
Signal strength is: STRONG. Full bars. Max 16 feet distance between parent and child. Includes 1 feet of concrete floor.
I have had these Deco M4 for 2.5 years and it was fine. Only after the ONU was relocated downstairs this issue started happening. Now that the ONU has been replaced 2 times already including cat5 cables, the issue is obviously on the deco set.
Right now I have connected a TL-WR841n to my ONU as primary. Then I have connected the Main Deco M4 via Lan cable from the WR841N and using it, there isnt an issue UNTIL:
- I connect my smart tv downstairs to Deco M4 Main and turn on youtube, the Deco M4 becomes yellow and I can see the LAN port goes down. Then after 5 mins it comes back up
- I run speedtest from my PC upstairs that is connected to Deco M4 Satellite, the Main M4 becomes yellow and again lan port goes down and restarts.
