Trackball cursor not showing on profile screen

[borez]

OK, weird one this: the trackball cursor won't show on my profile system, but when I plug in a different FOH rack to the same surface it appears so it's not the trackball itself and/or the connections. I mean it's obviously a problem with this particular FOH rack, but I can't work out what would cause it?

Any ideas?

Thanks in advance. ;)

OK, I think I've sorted this but haven't had time to test it yet.

FTR According to Digi: If you boot a venue FOH rack and the front power light doesn't come on but the desk boots normally, you also don't have USB power. Take off the front panel and there's a little white 4pin connector that can come loose, push it back in and you're back in business.