galvestonmac
New member
hi. I have a MBP 15" 820-3662 Retina with no backlight. I haven't worked with this model yet so I'm not sure of it's unique characteristics.
I can see an image on the screen if a flashlight is pointed at the back of the screen. Computer starts normally and chimes and external video works via the DisplayPort.
I checked F7700 and it was blown. LCI is red under LCD connector and there was some charring evidence on the underside of the logic board below where the LCD connector sits. No other corrosion is visible on either side of the board.
I replaced the fuse and connected the display again. No backlight so I checked the fuse again and it was blown again. I replaced the fuse again and this time also replaced the LCD connector. I powered it on again to test without the display connected. The fuse did not blow this time. I connected the display and powered up again. Still no backlight, but the fuse is not blown. Must have been some corrosion under the LCD connector that was shorting. I made some measurements on these components:
R7700 pins 1 & 2 12.6V
12.5v on pins 3 & 4
R7701 pin 1 12.5v
pin 2 12.6v
C7700 pin 1 12.6v
pin 2 11.6v
Q7706 pin 1 0v
pin 2 0v
3 11.6v
4 12.5v
5 0v
6 0v
C7701 pin 1 0v
pin 2 11.6
U7701
1 0v
2 0v
3 0v
4 0v
5 4.9v
6 4.9v
8 5v
9 12.7v
10 12.7v
11 11.1v
12 0v
13 0v
14 0v
15 0v
16 0v
17 3.2v
18 4.9v
19 0v
20 0v
21 0v
Any help would be greatly appreciated. I don't have another exact LCD panel to swap out, but I do have a 2015 Retina display. Would that work with this model?
I can see an image on the screen if a flashlight is pointed at the back of the screen. Computer starts normally and chimes and external video works via the DisplayPort.
I checked F7700 and it was blown. LCI is red under LCD connector and there was some charring evidence on the underside of the logic board below where the LCD connector sits. No other corrosion is visible on either side of the board.
I replaced the fuse and connected the display again. No backlight so I checked the fuse again and it was blown again. I replaced the fuse again and this time also replaced the LCD connector. I powered it on again to test without the display connected. The fuse did not blow this time. I connected the display and powered up again. Still no backlight, but the fuse is not blown. Must have been some corrosion under the LCD connector that was shorting. I made some measurements on these components:
R7700 pins 1 & 2 12.6V
12.5v on pins 3 & 4
R7701 pin 1 12.5v
pin 2 12.6v
C7700 pin 1 12.6v
pin 2 11.6v
Q7706 pin 1 0v
pin 2 0v
3 11.6v
4 12.5v
5 0v
6 0v
C7701 pin 1 0v
pin 2 11.6
U7701
1 0v
2 0v
3 0v
4 0v
5 4.9v
6 4.9v
8 5v
9 12.7v
10 12.7v
11 11.1v
12 0v
13 0v
14 0v
15 0v
16 0v
17 3.2v
18 4.9v
19 0v
20 0v
21 0v
Any help would be greatly appreciated. I don't have another exact LCD panel to swap out, but I do have a 2015 Retina display. Would that work with this model?