No backlight / Display 820-3787 after wrong LCD installed

Tony Tone

Q7706 pins 3&4 have 11V.
U7701 pin 11 has 11V
No output on Q7706 Change Q7706?

D7701(1) 0.851 D7701(2) 1.140
C7717 0V
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Staff member
Ignore backlight, we need display first. What voltage is on either side of L8300? Is LCD_PWR_EN present going into U8300?

Q7706 is related to backlight circuit. Backlight circuit is irrelevant until we have image. First image; THEN backlight!!

You do not replace Q7706 if it is not being told to open. Q7706 is P channel mosfet, so usually it will let power through when the voltage on the GATE(pin 3) is lower than the voltage on the source(pin 4) by a significant enough margin.

If the voltage on pins 3 and 4 are the same, there will be no output. Q7706 is doing its job, so you don't replace it!

R7701/R7702 create a voltage divider that U7701 allows a path to ground if it is told that backlight should be on. U7701 is not allowing Q7706 to pass voltage through because the machine doesn't think the LCD is connected/coming on.. so fix that first. Answer my above questions.

Tony Tone

Damn. Lost a learning opportunity. Customer is jumping up and down and wants their MacBook right now. So I'll give it to em.

Tony Tone

I know people are dumb asses. Masaratti dealer, snobbish. As far as I know, I don't think anyone else in town does board work. Gave him back just the bottom half of his Mac back. I'm not handing over my screen. LOL. Fuck but anyways. Ya I studied your videos for like 9 hours and tested, & tested to the best of my knowledge. I was also thinking as you are pointing out, but clueless. Thought I'd question Q7706 just because I wasn't getting voltage out even though I seen your explanation in videos. I will study what you have given me fa' sheezy : D Wish I still had that fucking board. Fuck the customer and their money I want to fix that fucking board LOL.

Tony Tone

Know what'd be DAF? If we put a deposit down on a board & only you know whats wrong with it & we tried to figure it out. Like different levels. Lemme get an easy one, LOL. & then ship them back to you. Not for pay or work, but as a learning tool. A computer class I once took the back wall was stacked with computers that the teacher sabotaged and we had to pick a random one and fix it.