Fuse Locations on MacBook Pro 17" 820-1249-A Logic Board?
I would like to know where the fuses are located on the Apple 820-1249-A logic board (Serial # last four: DD6Y). I want to test them for continuity.
Why? Beer spill! (It wasn't me… no, really!) (^_^);
1. Display first remained lit then went out.
2. Keyboard left side Shift, Option, Control keys non-functional.
3. Garageband won't start, QuickTime audio recording not functional.
4. Displays pane of System Preferences does NOT permit selection of normal default 1920 x 1200 built-in LCD screen option.
Other pertinent observations:
• External video works
• Light shined through Apple logo on display appears to indicate no screen activity, but not absolutely certain of that
• All other features appear to be functioning normally. (Determined through use of screen sharing and external video display)
Actions taken so far:
A. I have taken laptop completely apart.
B. Dowsed logic board in 99% isopropyl alcohol, soft toothbrush where it appeared necessary. Repeated 3 times.
C. Removed keyboard (except for cable) by stripping off black backing, separating clear/black mask, removing keyboard from frame, and again dowsing (with gentle scrubbing) in alcohol.
D. Similarly cleaned connectors, case interior, other parts.
E. Removed all logic-board-mounted parts (including speakers and heat sink) in order to both clean them and the board surfaces beneath them.
Prognosis so far:
a. Missing SysPrefs LCD display setting and possible lack of anything visible with substitute backlight point to WMCD chip issue as well as backlight fuse blow.
b. Audio processing portions of board may be due to fuse blow or temporary shorts due to spill residue.
I'm hoping that the thorough cleaning has removed shorts caused by the beer that only brought signals to ground and did not cause electrical damage.
And I want to be sure to test the fuses before I finish closing up the machine and testing it.
Many thanks for your help!
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