Lose connect HomePlug (Asus PLX32): Reboot of Homeplug or Router helps - Whose fault?

[Kusuri]

I have a homeplug (Asus PL-X32) set downstairs next to the main router and a 2nd one set upstairs to connect a PC to the internet.

Lately I've been having permanent drops roughly every 1 or 2 days only on the connection at the PC upstairs.
The PC downstairs connected directly to the main router can still use the Internet without problems.

The connection problem upstairs can only be resolved after either unplugging/replugging the homeplug there from the power or rebooting the main router downstairs. Unplugging/replugging any ethernet connections on either PC/homeplug/router makes no difference. Unplugging/replugging power of the homeplug downstairs also made no difference.

This is strange and doesn't make much sense to me, so I can't figure out what's at fault here.
Is it the HomePlug or could it be the Router? There's nothing in the router's log that can be of help and I don't have a different router or homeplug for testing.

Can it still be the Homeplug at fault even if rebooting the router is one of the methods that solves it? Anyone who knows well how the communication between a homeplug and routers work that could chime in on this? The best I could think of to do now was to switch places with the homeplugs and wait.

The router is still pretty new and in warranty (2 months left before it expires) which is why this is important for me.
Meanwhile I'm waiting for Asus to release the new PL-X52 homeplug as soon as possible...

[thiggins]

It is probably the homeplug adapters, especially if they run hot. Trying to swap the adapter positions would at least let you narrow the problem down to a single adapter.

When the PC upstairs loses its connection, check whether it still has valid IP address information.

[Kusuri]

Thanks for the tip. I'll make sure to try that the next time it goes down.