Jack Graham

Hey Have an imac i picked up on ebay for a fix up like i did with the imac im typing on right now i digress anyway when i...

My Macbook air just boots to a white screen no apple logo and when i try to reinstall os none of the Boot key commands...

It happens because you are overloading your plug with a power strip that has to many things connected and drawing too many amps try an extension cord from another know working outlet

you lucky dog just dry it out like others said take it apart and hairdryer tha SOB

the brown stuff is called underfill they use it at the factory so solder doesn't get everywhere i think your fine be careful with cleaning the pads they can break cuz they are held in with glue

This sounds Like a defective Lvds cable. The lvds cable carries the backlight signal and video signal within the cable if there is a loose connection in the cable wiring it will cause the symptoms you are having As a hobby i fix apple computers and i had a problem with a lvds cable that had severed video wires internally. The computer only presented a white screen when turned on no apple logo because it was only showing the backlight and no video signal

If i were you i would do a reflow of the board i had a problem with a mid 2014 imac that was getting no power to the no 1 diagnostic led it would flicker sometimes so i did a reflow in the general area of the LED and it worked. typing on the machine right now

The brass goes up when plugging in

Update: got the mac working Got the psu in with no change so i pulled up the schematic and probed the output of the psu 12v still no led no 1 so i found the led on the schematic and it said 3.3v on positive side of led (3.3 is the trickle voltage from second smaller connector on psu) probed led no 3.3v (i noticed that the led would flicker sometimes so i thought loose connection at a solder joint) when i applied pressure to led it would flicker more often) so i reflowed the led area and the MAC TURNED ON i remeasured the led and got 1.2 v when its supposed to be 3.3v checked a cap right next to it and got 3.3v on one side and 1.2 on the side going to the led so i think the heat reformed the cap and fixed a bad solder joint FYI IM WRITING THIS ON THE MAC IN QUESTION

Got it Diagnosed turns out the lvds cable had some broken wires where the hinge on this machine was broken with the bad lvds cable CONNECTED TO THE LOGIC BOARD i was getting a white screen with no apple logo and the macbook air would not display anything other than a white screen even with trying to boot to a usb holding option. THE FIX: i disconnected the lvds cable from the logic board because even when i tried to use an external monitor nothing would happen with it still connected ( wires being broken must have grounded the video signal or broken a feedback loop?) as soon as i disconnected the lvds cable from the logic board and tried an external monitor again i got a BLINKING FLASHING FOLDER ON THE EXTERNAL MONITOR SUCCESS!!! i was even able to boot to a usb (in order to do this on a macbook air you must disconnect the hard drive cable from the logic board) I HOPE THIS HELPS SOMEONE