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Step 2Find the test point
The large chip there is the microcontroller that interprets signals from your keyboard and touchpad and converts them into mouse position data; it also reads the button. Note that the keyboard has to "talk" to this to work -- unlike desktop Macs in which the mouse connects to the keyboard, here it's the opposite.
Now, look at all those gold-colored dots on the circuit board. Those are test points that can be used by technicians to access various functions of the hardware to test it. Note the small wire going to the touchpad button -- that also leads to a test point and eventually to the microcontroller. The button shorts to ground when pressed.
If you have a voltmeter you can verify this by setting it to continuity check and touching the trackpad's chassis and any of the 4 small contacts on the button; two of the wires will "beep" always, the other two only when the button is pushed.
Near the main chip, look for 4 test points placed like the arrow keys on a keyboard. You want the "right arrow" in my picture. Pulling that to ground marks a secondary click (aka right click) event to the microcontroller, which dutifully reports it to the rest of the laptop.
Now, look at all those gold-colored dots on the circuit board. Those are test points that can be used by technicians to access various functions of the hardware to test it. Note the small wire going to the touchpad button -- that also leads to a test point and eventually to the microcontroller. The button shorts to ground when pressed.
If you have a voltmeter you can verify this by setting it to continuity check and touching the trackpad's chassis and any of the 4 small contacts on the button; two of the wires will "beep" always, the other two only when the button is pushed.
Near the main chip, look for 4 test points placed like the arrow keys on a keyboard. You want the "right arrow" in my picture. Pulling that to ground marks a secondary click (aka right click) event to the microcontroller, which dutifully reports it to the rest of the laptop.
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Jan 22, 2009. 7:05 PM
jeff-o
says:
jeff-o
says:
Hmmm, sharp pictures would really be helpful here.
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1
Jan 23, 2009. 12:10 AMspiritplumber (author)
says:
I only have a cellphone for a camera at the moment :) do you have any suggestions? I thought about making the photos into drawings.
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Jan 31, 2012. 7:51 AMgmichaelt
says:
Take the lens from a dead optical drive, judiciously mount it in a convenient holder, and secure that holder to the cell phone, directly over the lens of the phone... There's an instructible showing how that can be done, I believe. Haven't tried it myself--I don't have a cellphone.
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34
Jan 23, 2009. 3:56 AMjeff-o
says:
jeff-o
says:
Hmmm, aside from getting a dedicated camera I'm not sure what to suggest. I suppose the photos you have are about as good as it gets for a cell phone camera - they're not so great for macro shots! Vector drawings could help too, though that's a lot of work. I think that one ought to be enough, just to show where everything is. That should help people get aligned, then they can follow the written instructions more easily.
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1
Jan 23, 2009. 5:12 AMspiritplumber (author)
says:
Thanks, good point :) I'll do that after work today.
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Jan 23, 2009. 7:43 PMKittymew
says:
Work kinda never ended today, sorry about that; I'll try to remind her about the vector drawings, we had a rough day.
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