Last week I regretted agreeing to help a friend with a new installation, because it gave me a lot of trouble.
I went round again yesterday, to sort a few things out. One really annoying problem was the connection between his ADSL router (upstairs) and the Time Capsule (downstairs).
Sometimes it worked perfectly for hours at a time, before becoming mysteriously intermittent. I changed the plugs on the cable multiple times, carefully examined all its visible bends (most of it went safely behind walls and under floorboards).
I really couldn't make head or tail of it.
After an hour or more of head-scratching and watching the blinkenlights sometimes blink and sometimes not, Rob was bringing me a cup of tea. The light went out again, then came on again.
I called down the stairs: "Take a step back please". The light went out.
"Step forward". After a moment, it came back on.
"Step back." Off. "Step forward." On.
It turned out there was a precise spot on the landing, and standing on it would knock off the connection. A few seconds after stepping away, it would return.
We tore up the carpet and lifted some floorboards. The ethernet cable had been moved, probably by some workman, and was being pinched by a slightly loose floorboard.
Daniele