[SOLVED]820-2879 back from the dead but...

[george-a]

Hi guys,

This one was LD and after UC it came back to life when U7000 was replaced (there was a hole in it). The LVDS connector pins were re-soldered and remaining board checked for shorts before powering on. All clear.

NOTE: touchpad not working - left disconnected.

Now it starts, it chimes, it starts booting but after 10 seconds the FAN goes to full speed and 30 seconds later - before finishing boot up - the screen fades to black. It stays there - powered on and the fan at full speed. I

I also noticed that when you try to choose boot disk (pressing Option at chime) using keyboard arrows the change from one option to the other is REALLY slow.

I checked U5515 and surrounding resistors for corrosion and look good.

Should I try a diagnostic (I think 3S138 is the right one)? Where should I look next?

thank you dudes.
george

 

[aprendiz]

Corrosion on trackpad connector, check if PP3V3_S3_TPAD is present at pin 22 of J5800 also check pin 21 PP18V5_S3 (trackpad connected), If voltages are ok and connector is not corroded try other trackpad ....The trackpad is not detected this is why it is slow and fan at high speed...

Screen fade out could be SMC_LID problem, clean all that crap on the connector and check if SMC_LID is high...

 

[dukefawks]

Of course the fan will run high without the trackpad connected.
Screen going off is SMC_LID issue. Corrosion under BIL connector, bad pull up on that line, etc.

 

[george-a]

Ok guys, you were correct as usual. I had to remove the BIL connector to make SMC_LID go high and finish booting. The trackpad had also some crap on the flex side (not that visible) and after some cleaning, it worked as expected. All voltages are present and pull-ups measure correctly.

I also re-balled the SMC incase the was some crap there, too. Probably unnecessary but it was a good experience (first time)! Photos are for viewing pleasure - maybe a video as well in the future.

Many thanks!