820-3115 chime but no display

Repairable

Active member
820-3115 board. came in water damage.

now it chimes but i get no image (when i shine a light on the back i see no apple, also not with a different screen.)

i have 3,3volts on J9000 pin 4 so it is recognizing lcd.

I am missing LCD_IG_PWR_EN 0Volt.

LCD_IG_PWR_EN comes from U1800
but am I wrong to think if I get a chime then u1800 gets power?

what am I missing
 

ALB-Repairs

Member
Im Assuming youve inspected the LVDS connector? try shine a light on the inside, see if the connectors burnt. Yes all main power rails are present if you are getting a chime.
 

dukefawks

Administrator
Of course USB mouse will light up, it is chiming.
LCD is NOT recognized pin 4 is connected to 3V3_S0! SMC_LID high?
 

MDY

New member
In this board I found out that if lvds connector is bad then LCD_IG_PWR_EN will appear only for first 8 segs. So you must check as soon as you connect magsafe.
Duke will correct me if I am wrong.
 

Repairable

Active member
pin 4, 6, 7 al are 3,3volts

R9008 is 9,85k when no lcd kabel connected
R9009 is 9,84k when no lcd kabel connected

red on pin 6 black on pin 7 gives me 19,87k lcd kabel not connected.

with kabel connected is drops to 6.4k (don't know if that normal don't have a second machine for testing)
I don't think that's good, but Ill wait for you :)
 

G.Beard

New member
FYI I think the USB mouse is to test if BIOS initializes USB. Also good way to check if a fuse has blown to USB port if you get one non working port or whatever.
 

Repairable

Active member
No lcd connected
pin 6 0.542
pin 7 0.544

Lcd connected
pin 6 0.562
pin 7 0,502

red on ground.
 
Last edited:

Repairable

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hmmm, finaly got the kabel in and back from vacation..

Best wishes for you all.

pin 4 solid beep.
pin 6 solid beep
pin 7 solid beep.
 

Repairable

Active member
oke got a second machine in just now, and that ones working I hooked up the board to that screen, but no luck still nothing
 

Repairable

Active member
lcd works on other logic board.
every pin on j9000 measure the same as on the working board.

LCD_IG_PWR_EN stil no where to be found. bad GPU ?
 
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