Hi.
I have been experiencing this issue as well.
I have new MBP 2.4 and the left USB will power my TF but send no data. The right USB will power and send signals but only for about 10mins.
I changed cables thinking the cable might be faulty. And same problem. I have also power the TF unit itself with the correct power adapter.
Now here is where it gets weird. I have a Ecler NUO4 audio/DJ mixer which has midi capabilties. So I plug my MBP in and connect up modul8. No problems. Seems to work fine for over 15mins. (some of the rotary/endless controllers confuse modul8 but I'm sure given time I could tweak it.)
Now I plug in my TF in place of the NUO4 and remap/reconnect the midi. Works fine for 10mins again. So I try the same cable as that of the NUO4 and it seems to be fine. I tested for about half hour which no disconnect.
Looking back at the 2 previous USB cables tried they both have the same code and that on the wiring. Which is different to the cable that came from my NUO4.
So I think that maybe the USB cable was a lower grade or possibly only designed for USB1? Which is weird as I would imagine a TF would only need USB1 as it is only sending midi signals. Unless it needs the power sent aswell, but as aleady mentioned, even with a power supply to the TF. Sod all difference.
Oh, it still doesn't work in the left USB socket. Which apparently isn't an Apple thing, it's manufacturers overrating their USB devices against guidance...
http://discussions.apple.com/thread.jsp ... 5&tstart=0
Has anyone tried this setup thru a USB hub? I don't have one to test. But am quite annoyed really at having spent nearly £2000 on this new top of the range kit and I get one sometimes working USB port.

nutta as yet.