Pattern to record: Automatic power-on may work while pressing the power control does not.

Use the correct Mac power design

Intel MacBooks span MagSafe and USB-C charging designs. Match the diagnostic procedure to the model and connector; a USB-C negotiation test is irrelevant to a MagSafe-only machine. One possible explanation is that the keyboard, top-case or button line is not delivering a valid start request.

Power and data precautions

Disconnect internal battery power before handling board connectors. Shorting board points is unsafe and can damage adjacent circuits.

Model-specific checks

1. Separate SMC state, memory or storage symptoms from missing power rails using model-specific tests.
2. Compare alternative supported startup triggers and trace the button signal with power isolated.

Repair and startup verification

If the checks support this cause, repair the button, top-case connection or signal path confirmed by testing. Verification should cover cold start, charger and battery operation, sleep, wake, restart and thermal response.

For an assessment of your Intel MacBook, contact AEPC in Burswood or call 027 908 8880. Provide the model and the conditions that reproduce this problem. Workshop visits are by appointment.