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820-3330 no video

J

jadao

Member
I got this board witch has been messed with a little...It got a sticker with (bad video card/Bios)
Hopefully GPU has not been reflowed.
I took a look at it and here is my findings:

Initially quarter fan spin...nothing to do with charging sense resistor
L3508 completely burned...but thats not a big deal.
Wrong 2011 lcd plugged in...
Looked for knocked off component and found R8802 in another position! between R8802 pin1 and c8823 pin 1. R8802 pin 2 was not anymore connected.

Corrected all this stuff and still board with all signals power cycling...

Decided to quickly test a bios from same donnor board and actually it chimes! but still no video! Usb mouse with red light.

U8900 had very bad looking original solder joints. I decided let's touch up and reflow all the solder joint, It looks really great but nothing changed, still no video...

Tried some PRAM and checked for image but nothing.

Then I thought maybe bios should have it's original ME, so I tried a backup from the original bios and it's not detected by programmer. When I solder back bad original bios chip it has same diode mode reading than the donnour testing one...
Actually it looks like it does'nt turn on but no short!! When I remove original bios it doesn't change anything, it continue power cycling.

Is it worth spending time for this? If so how can I confirm if it's a bad ME bios chip causing that or a bad U8900?

Note: I confirmed U8900 is receiving GPUVCORE_EN 3.3V and GPUVCORE_PGOOD at 3.3V. Found also PPVCORE_S0_AXG to be 0,89V, so it looks very likely that U8900 is working properly.

Thanks for any advice
 
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2informaticos

2informaticos

Administrator
Staff member
Did you test for external video.
Instead of mouse, test with OSX pendrive; if flashes, there is USB activity for sure.

"GPUVCORE_PGOOD at 3.3V"
That means GPU power supply works good.

Post some voltages at J9000; correct LCD plugged in, of course...
 
J

jadao

Member
Yes I tested with external monitor, it doesn't work.

However I am sure there is activity,, it chimes, I can PRAM the board with external kbd.
I also see flashing activity with my usb live os hdd,
When I boot holding option key, I can see Caps Lock key light on.

Voltages on J9000:
PP3V3_SW_LCD=0V I am missing LCD_PWR_EN = 0V

Thanks
 
J

jadao

Member
Hi 2informaticos, thanks for the dumps I downloaded it, but I can't open the compressed file, it seems broken.
Thanks
 
J

jadao

Member
Sorry, for some reason it’s missing a line,
Since I can’t open your dump, the compressed file is reported as corrupted (maybe it’s my win xp system :), I’ve downloaded from Vinafix a bios to test. They had a 8MB version and a 4MB.
I just took a standard 8MB version.
 
J

jadao

Member
So I tested another bios (with no warranty wether clean ME or not) and samed thing...
it chimes, it's able to PRAM but no image/backlight...
Any suggestiona? Thanks

I notice also fans doesn't ramp up due to missing trackpad, it just run quiet as if trackpad was connected??
 
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J

jadao

Member
Any suggestion about this one before I give it back? Thanks
Don't know if on this model fan ramp up progressively to maximum when trackpad is disconnected… I think it should if TS0P is located on the trackpad…
I don't know if this is most likely related to bad ME region or other additional issue...
 
2informaticos

2informaticos

Administrator
Staff member
No external video discard a problem with internal LCD.
You must have a GPU related issue.
Change U8900, just in case...
 
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