820-2936-B Green light charger, white screen, fan is fast, no folder w question mark

[kanadaguy]

I did some work surrounding the U7000 chip.. Now i get a white screen and the fan turns on really high and I don't get the folder with question mark - Is this a PCH issue?

My charger gives me the green light and I am getting a white screen with no folder with question mark and the fan turns on super fast. I can't get to a screen to be able to run ASD to check sensors...

Does this sound like a PCH issue?

 

[dukefawks]

Getting voltage to C9015? Can you do a PRAM reset?

 

[kanadaguy]

Getting voltage to C9015? Can you do a PRAM reset?

Do you mean a SMC reset? Doesn't SMC control the fans and such? I am by no means being a jerk just trying to understand why you would suggest a PRAM reset is all..

Also you are correct there is no voltage on C9015 and pin 2 on LCD cable looks burned out which is also on the same line.. PP3V3_LCDVDD_SW_F

Thanks for your previous prompt response!

 

[kanadaguy]

Getting voltage to C9015? Can you do a PRAM reset?

I checked to see if the cap was shorted but it is not, also the pin 2 on the LCD may look like crap but it has continuity from pin 2 on LVDS connector to the cap C9015 and to the inductor that follows beside it L9004...

 

[kanadaguy]

Getting voltage to C9015? Can you do a PRAM reset?

Sorry for so many responses I should have waited and gave my results after investigating.. So I checked everything on that line and everything is good so it lead me to the U9000 and it is not getting any voltage on its enable pin so nets LCD_IG_EN. This is created by u1800 PCH correct?

So my questions are:

First What does the PP3V2_LCDVDD_SW_F do exactly? I'm guessing it has something to do with switching something on related to LCD? I get a white picture so isn't the LCD getting a image?
Second What should I do at this point?

 

[dukefawks]

Did you test the voltages on U9000 with the LCD plugged in? Check pin 1 with LCD plugged in, must be high.

 

[kanadaguy]

Did you test the voltages on U9000 with the LCD plugged in? Check pin 1 with LCD plugged in, must be high.

Indeed you where correct I did not have the LCD plugged in... The device is booting and getting to the folder with the question mark however the fan is really running fast which is making me think something is overheating.. I tried to boot up a copy of iOS through a usb drive I have and it runs super slow... I don't have a copy of ASD for this particular model. Would you suggest I grab that? Or any other suggestions?

 

[kanadaguy]

Did you test the voltages on U9000 with the LCD plugged in? Check pin 1 with LCD plugged in, must be high.

Could it be a short under the PCH causing this?

 

[dukefawks]

It is a sensor issue and you need to run ASD. Common fault is the trackpad sensor, is it connected? You should download the ASD torrent, google for it, it is all ASD and is 56GB or something.