820-3332 - Chime, No Image

[tlough75]

I got on the table an 820-3332 that draws 1.4 amps, has chime and MS light, but fans ramp up to max RPM and backlight comes on immediately when laptop is powered on. This board has clear signs of previous work on Q9706, U8900 and U5550. There was flux all around U8900 and U5550 and after I cleaned it off I could see the poor soldering job that was left. I re-soldered both chips but that didn't change anything. PPVCORE_GPU is .7V and 10.3 Ohms to gnd. I have a working version of this board for comparison and the working board is 34 ohms to gnd.

LCD_PWR_EN: 0V
PP5VR3V3_SW_LCD: 0V

 

[tlough75]

Those reported voltages were measured both before the re-soldering and after by the way.

 

[2informaticos]

CPU should be good, if you get chime.
Confirm if board has USB activity after 30s and doesn't get stuck.

Did you resolder U8900?

 

[tlough75]

Confirmed chime
USB: Solid light, no activity
I did re-solder U8900

 

[2informaticos]

If board gets stuck, there could be GPU problem.

I hope you've properly checked the USB activity.
Read here, just in case...

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...

boards.rossmanngroup.com

 

[tlough75]

Ok, yeah, confirmed by plugging in my USB boot drive with bright red LED into working machines