usb cam recognized by icam but no picture

[me2]

mac os x 10.6.7 - built-in isight and a 2nd firewire isight camera work fine.  i bought a usb 2 camera that shows up in the add camera window but never delivers a picture to icam monitoring window or ipad app. 

this usb camera works in skype as the others do - any ideas or suggestions would be appreciated. 

thanks

[me2]

ah ha, so you can't have isight (firewire or built-in) running at the same time as a usb camera?  that seems kinda silly...

[SKJM Support]

"We've heard reports of problems of certain Mac models that prevent multiple USB cameras working simultaneously due to an issue with the USB bus. It isn't a problem with iCamSource in particular, because the problem occurs with other programs as well. 

You can find out if this is the problem you are experiencing by trying to open two of the cameras in different programs simultaneously (such as iChat or Photobooth).  For example, open one camera in Photobooth and then try to open a different camera in iChat."

[me2]

okay, more info - tested with both ichat and photo booth...  usb and firewire sight cams will work together.  however, built-in isight (newer iMac snow leopard) won't work with the usb cam.  firewire isight does work with built-in isight but of course that's all apple stuff.

so now i do have icam working with usb and firewire isight cams.  next test is to find out if more than one usb cam will work on the usb buss.