Working on an 820-00840 board that had no camera. Tested it in several assemblies as I know the cameras in these panels love to fail. All power lines measured fine around U3900, but I had seen someone about a year back mention the ALS SMBUS sensor causing issues with the camera SMBUS line, so I pulled R8556/8 and camera functionality returned. So issue was definitely the ALS SMBUS line.
I'd love to repair it "properly" of course, and I imagine the fault lies in the SMC. However, since ALS is tied to the main SMBUS line, I would expect a fault to affect other things as well (high fan, etc) or at least cause an error in AHT, but it didn't. So my question is, would replacing SMC in this case even help?
I'd love to repair it "properly" of course, and I imagine the fault lies in the SMC. However, since ALS is tied to the main SMBUS line, I would expect a fault to affect other things as well (high fan, etc) or at least cause an error in AHT, but it didn't. So my question is, would replacing SMC in this case even help?