Location of Hall Effect [Lid] Sensor

Thanks. To clarify: The short answer is, "yes." I found the sensor attached to the top-facing side of the I/O board, on a riser as Tom described. I was able to verify that powering-up the laptop with the I/O board removed did eliminate the sleep problem--but, of course, introduced an array of new problems. Unfortunately, cleaning and reattaching everything did not resolve the issue which returned with the I/O board reinstalled, But, I'm anticipating that a replacement will resolve the issue.

My replacement I/O board arrived yesterday, and did indeed resolve this problem. Thanks again.

Hi, i have the same problem with a1502 mac pro. The MacPro went to sleep randomly and waked up soon with open lid. Do you have any part number or picture of the up side of the logic or io board?

Here's the IFIXIT guide to replace the I/O board: MacBook Air 13" Late 2010 I/O Board Replacement. Often I find I need to replace the I/O cable as that sometimes gets damaged. As to a picture of the other side not much to see here: I/O logic bod from Mid 2011 model which is almost identical The Hall sensor is the square block just under the cable harness. I would try using a magnet placing it near the left side Tab key to see if it goes into sleep mode.

Thanks for your quick help. I think i can't solve this an simple part replace.