Pattern to record: The charger cycles or current draw rises without normal startup activity.

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 a component on a standby supply is drawing excessive current before startup.

Power and data precautions

Disconnect internal battery power before handling board connectors. Blind voltage injection can damage processors and storage.

Model-specific checks

1. Separate SMC state, memory or storage symptoms from missing power rails using model-specific tests.
2. Measure resistance with all power removed and isolate the affected rail without heating sensitive parts.

Repair and startup verification

If the checks support this cause, replace the confirmed shorted component and inspect its supply stage. 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.