820-3332 green light, fans spin, no chime

[Cocobill]

Hello,


I got this logic board 820-3332, got a green light, both fans spin, no chime. I retouched the joints of U8900, nothing changed.


PPVCORE_S0_CPU is 0.825V

ALL_SYS_PWRGD is 3.3V

PPVCORE_GPU is 0,896V


Anything else to measure? Any ideas?

 

[JohnB8812]

PRAM reset done?

 

[Cocobill]

I did reset PRAM, no luck.Is PPVCORE_S0_CPU at 0.825V OK?

 

[dukefawks]

Vcore is fine. Does a USB mouse light up? Any other history?

 

[Cocobill]

USB mouse is lighting up. No history, thought... other than no water damage.

 

[dukefawks]

Do a PRAM reset with an external USB keyboard. Disconnect the internal keyboard. USB mouse is lighting up so the board is doing something.
Is GPU Vcore present on L8930?

 

[Cocobill]

Hello Duke,

Disconnected keyboard, did PRAM reset with external kb, GPU Vcore on L8930 is 0,895V...

 

[Cocobill]

Is GPU Vcore on L8930 measuring 0,895V correct? What else can I measure?

 

[dukefawks]

How do you know you did a PRAM reset? Is the board chiming now? L8930 is correct voltage.

 

[Cocobill]

For some reason now it chimes every time I start it. So with external keyboard I did PRAM reset. I still get no image/backlight. How do I know that I get an image but no backlight, or if I get no image at all?

 

[dukefawks]

5V present on L9000? Hold flashlight to apple logo and check for image. Is the LCD known good?

 

[Cocobill]

LCD is known good. L9000 is 5V

 

[dukefawks]

There is most likely an image then. Hold flashlight to the Apple logo and check

 

[Cocobill]

I can't see anything. Disconnected display, plugged a monitor via thunderbolt. Booted from battery and ASD OS test hangs at the following point in verbose mode:


Macx_swapon SUCCESS


Booting from USB with El Capitan in verbose mode hangs at:


fInterfaceSnapshots is missing


Running ASD Efi shows the desktop but I get the error





Sensor Voltage (VBLC) --Backlight (test1) = Error - Sensor is reading below the low limit.

 

[dukefawks]

Was U6100 messed with?

 

[Cocobill]

No, it looks immaculate.

 

[dukefawks]

Read chip and upload dump please.

 

[Cocobill]

Well, I'm pretty new at this and have no knowledge or tools to do this. I know it is off topic, but can you link to a site that will teach me that? Thank you.

 

[Cocobill]

Would this

https://www.ebay.de/itm/NEW-TL866CS...hash=item362ce55a5a:m:mb1ZGy0Nq_st7Newwg_2mAA

do the trick? Since this SPI chip has the legs parallel to it, not bent 90 degrees, do I need a special adapter to connect?

 

[Cocobill]

Or, can I use my Arduino?