Clip not recognized as USB device, but charging on USB works
recently my Sansa Clip stopped being recognized as an USB device. When I plug it into an USB port the battery symbol indicates charging (and indeed the Clip is charged), but otherwise nothing else happens. The screen does not switch to the "connected" display nor does a new drive shows up on the computer. I have the Clip in MSC mode, but changing it into MTP mode does not work either, no connected screen, no device found on the computer. I checked it on three different computers with three different cables, no luck. On all computers it worked before. Using the menu option to reset the Clip had no effect. The firmware is 01.01.20E.
Another odd thing: when I try to reset the Clip by holding the off-switch for 15 Seconds nothing happens, except that the Clip is normally switched off after about a second.