On Dec 1, 2011, at 2:04 AM, Lists wrote:

> I'm pretty sure, when Apple *did* start using USB internally, they routed the 
> keyboard and trackpad through the *same* USB hub (erm, is that the correct 
> term?) as the external ports,

No I do know that the USB keyboard and mouse have always presented as a 
separate hub. I'll have to look in System Profiler on my PBG4 at home tonight 
to see what it is.

> so you'd kind of expect a global USB failure to be present. So, if it is 
> internally USB, the only other think I can think of, past what has already 
> been suggested, is that the actual keyboard/trackpad device might be having 
> an issue as a USB HID? Is it a self contained unit, or is some of the device 
> broken out on to the main logic board?
> 

The keyboard and trackpad are separate units, but are interconnected on the 
wiring.

Stray thought just hit me....Web cameras and the like use CCD's that are quite 
sensitive in the IR (point a TV remote at your web cam and press the buttons 
see what you see), and actually have IR filters so they don't burn out in 
bright light. These filters are reasonably easy to remove 
<http://www.instructables.com/id/Making-a-Night-Vision-Webcam/> 

I wonder if such a modified web cam might not be a useful tool for identifying 
possible electronics failures, as the typical failure mode for intermittent 
issues like this is a short circuit or poor connection that breaks when 
something runs too hot; aiming a modified camera at the logic board might 
identify the 'hot spots', helping isolate the problems...

-- 
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group

Institutions do not have opinions, merely customs


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