Apple Macbook Pro Aluminum 13-Inch Black Laptop Keyb Technical Guide - Page 51

2010-06-15 Noise / Hum / Vibration Unlikely cause: RAM, display assembly, top case, camera, microphone, battery Quick Check Symptom Noise / Hum / Vibration Computer or AC adapter emits a noise or vibration. Quick Check 1. Verify and reproduce the source of the noise from the computer / adapter with the customer. 2. If the AC adapter is the source of the noise disconnect and try a known-good adapter. ( a small amount of hum or vibration is normal with AC adapters ). Deep Dive Check Result Action Code 1. Use of a known-good AC Yes adapter eliminates the noise/ vibration. No 2. Verify if the noise is heard Yes through the speakers and / or headphones. No 3. Disconnect any peripheral Yes devices, cards, or cables attached to the unit. Verify the noise is gone. No 4. Locate the source of the noise. Yes Is the noise from an optical drive? Replace AC adapter. P04 Go to step 2 Go to step 3 Go to step 4 Check for possible ground loop. Go to step 6 Check with a different media J04 disc. Possible issue with disc label or out of balance media. If not related to media, and noise is above normal level, replace optical drive. 5. Is the noise from the hard drive? No Go to step 5 Yes Drives normally make noise H06 when starting up or when the heads move. Replace drive if noise is above normal levels. No Go to step 6 MacBook (13-inch, Aluminum, Late 2008) Symptom Charts - Startup and Power Issues 51