MacBook Pro (15-inch, Mid 2012) 820-3330-B No Image

[bcherdak]

Hey guys, I have a 15-inch, Mid 2012 Macbook Pro that came in with no image and I tested it with a known good/working LCD (with working lcd cable too) and there is also no image externally through thunderbolt

This is not the 820-3332 Retina model with the u8900 that needs to be retouched.

The logic board is spotless on both sides, very well taken care of by customer, customer stated they were using it, shut it off, went to lunch and came back, when he turned it back on, the computer chimed, but there was no image on the screen.

820-3330-B, I dont think this board is the one with the GPU issues.

The macbook chimes, keyboard lights up, SMC and PRAM work.

Capslock works, external mouse lights up.

One thing I notice is the Sleep Indicator Light (SIL) stays on when the lid is open and/or when the lid is closed.

The voltage for SMC_LID is normal at 3.4V

U9701 (backlight) is clean and no damage

U8900 is clean and no damage either.

Anyone has any clues on what might be the issue?

 

[2informaticos]

Any history available?
No image, nor backlight?

Disconnect internal LCD, connect to external monitor and give it time to enter OSX; possibly no external video before.

Post voltage for J9000, pins 2/3, 4, 6, 7, 38-40.

 

[bcherdak]

Any history available?

Computer was very well taken care of, battery is in very good condition when it comes to cycles. Kept in a case, very minimal dust inside of machine. Nor any damages on any corner or surface of the machine.

No image, nor backlight?

Both no image and no backlight, shined light from the back of the lcd, no blinking folder or apple logo.

Any history available?
Disconnect internal LCD, connect to external monitor and give it time to enter OSX; possibly no external video before.

Tried that, waited up to 10 minutes for a blinking folder but there is no image, I even connected a hard drive with a hard drive cable and still no image.

Any history available?
Post voltage for J9000, pins 2/3, 4, 6, 7, 38-40.

Currently out of the office, will post with voltages in a bit, Do you want voltages with lcd connected and no lcd connected?

Thank you for your support!

 

[bcherdak]

Any history available?
No image, nor backlight?

Disconnect internal LCD, connect to external monitor and give it time to enter OSX; possibly no external video before.

Post voltage for J9000, pins 2/3, 4, 6, 7, 38-40.

Pin 2/3 - 0.2 MV
Pin 4 - 3.35 V
Pin 6 - 3.35 V
Pin 7 - 3.35 V
Pin 38-40 - 0.02V

Thank You!

 

[2informaticos]

Reflow GMUX and see what happens...

 

[bcherdak]

Reflow GMUX and see what happens...

I was thinking about replacing U8900, do you think it might be the issue? Or does GMUX send those signals?

Are there any voltages around the u8900 you want me to send you?

 

[2informaticos]

U8900 is not a common issue on this board.
Do you get GPU voltage?
Reflow it if not.
But you should reflow GMUX...

 

[bcherdak]

U8900 is not a common issue on this board.
Do you get GPU voltage?
Reflow it if not.
But you should reflow GMUX...

To test GPU voltage I check GPUVCORE_EN or GPUVCORE_PGOOD?

I reflowed it but still nothing?

 

[2informaticos]

"Do you get GPU voltage?"
L8930/60...

 

[bcherdak]

"Do you get GPU voltage?"
L8930/60...

Hello and happy new year! I will check that when I get back into the office, I did discover a bit of corrosion under the U9600 when removing the edge bonding, so I am currently trying to find a stencil to reball the old chip or I have to find another. Will a U9600 from a 2011 15" work on a 2012? (820-2915 GMUX on a 820-3330)

Please let me know.

 

[2informaticos]

I recommned you to get GMUX from the same donor board, as it has firmware.

Please do NOT quote an entire post from few cm above...

 

[bcherdak]

Alright, if I dont have a gmux from the same donor board (820-3330), is there any place I can get one such as a reputable online supplier or can I use one from the 2011?

 

[2informaticos]

Buy scrap boards from eBay, or Aliexpress.
Or contact Paul Lee through Skype.
Is the same galaxyelectronics2015 from eBay.

 

[bcherdak]

"Do you get GPU voltage?"
L8930/60...

L8930
PIN 1 - .9 V
PIN 2 - .9 V

L8960
PIN 1 - .9 V
PIN 2 - .9 V

Looks like I am getting Voltage,

I also replaced GMUX with a new one from a donor board of the same board number and text on it.

I am getting 0V on output on U9000 (LCD LVDS INTERFACE)

Pin 1 - 0V (LCD_PWR_EN)
Pin 2/3 (IN) - 3.4V
Pin 4,5 - 0V