Yun2 losing network connection

Hardware Arduino Yún
1

I have a Yun Rev2 which is connected to the network via the LAN cable (I think this is labelled as interface wan in luci). Occasionally it loses connection and I have to reboot it. When I first bought (last week) it I had trouble connecting it. I have 2 other Yuns (rev1) which use DHCP and I've never had a problem with them. But this Rev2 board just didn't operate properly. Sometimes it comes back without a reboot, say after 10mins. Also, if I do 'ls -l' at the shell I get garbage like this:
+��
�
�������j�jV���j�����ie�������k
��J
��l�ӵ�����c�5���ڮ7�i����H
���y�

What's going on here? Does anyone else have these problems? Or should I suspect some hardware malfunction?

If I can't list a directory using ssh, there's little point trying to fault find anything!!

2

Actually, that garbage are real files all having been created in the root directory today. Thre are thousands of them. Quite how they got there and how I'm going to remove them is indeed a conundrum.

update...
So I removed the files with rm -- ?*

I think an unstable power supply may have added to my problems. I added 100uF capacitor and so far no LAN disconnects.