820-00045 no display

arnonabuurs

New member
Hi I have a Macbook 12 inch with no display external and internal also tried a good working display. The machine is turning on as all powerstates are there including S0 and cpu gets warm and has power. Display is missing backlight power as well as 5V, 3.3v is present. Q7706 has 8.6v on pin 3/4 and on the otherside once i got 8.6 and mostly 0.44v. For PP5V_S0SW_LCD, which is 0v, as well as U7701 the enable signals are 0v. Any idea how to troubleshoot this piece of junk :)?
 

dukefawks

Administrator
The usual common 00045 issue. I have no idea what it is at this time. If you want to experiment start with swapping out U4700, the common failure on these.
 
worth a try, all seems to be OK all voltage is there no shorts also not on U4700
If you connect just the DCIN and display to the board, do you get image/ backlight with a good display? Had another couple of these that were crippled by the keyboard and tpad.
if you get image, shut down and plug things in one at a time. See what prevents it from working.**make sure to disconnect the batt each time**.

Let me know now what you find. Seeing a lot of this similar issue on these.
 
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TCRScircuit

Super Moderator
Staff member
I've had the same things with me. I think on some its possible that U4700 is half dead and hangs up POST. For the rest I have no idea
 

arnonabuurs

New member
OK will try, the first one i got didnt work with a good known display, but now I just got another one in exactly the same issue. All voltages upto 1.05 sus are present but no display.
 

arnonabuurs

New member
Ok the second one i got works with a good working display. SO thats gonna be an easy one :). For the other one waiting for the U4700 and i will just try to swap it see if it makes a difference. I dont expect so, as there is no short there.
 
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