820-2850 No power. Green light only


hey guys. Been a while since posting. Must of learnt something!
Am now stuck on a old 820-2580 board. Seconds away from giving up and this post is my last resort.

PPBUS_G3H is not holding and is always changing values. From around 8v to 12.6v.
F7040 is fine and I even changed U7000 off a working board. Same result.
R7020 and R7050 are those sense resistors. I don't quite understand how they work although the readings seem fine. Can't find any shorts.
Possible for some nudges in the right direction??
Thaks again.


So here's an update.. ended up repalacing the board that caught fire. Bought a supposedly working board from eBay, Rnrcomputers to be precise. Long story short. This board doesn't work either. Has no green orange light.

Took 3 weeks to arrive and really don't have time to send it back and wait so I thought I'd diagnose. Found CHGR_CSI_R_N between r7020 and r7022 missing. Jumped it. Got a green light and laptop powers up and all works bar an x for the battery.

So the smc is not seeing the battery I'm guessing.. And pins 4 and 6 on the battery connector are the lines that tell the smc there is a battery?? Am I on the track?

u4900 creates smbus_smc_bsa_scl and goes to battery then to u7000

i cant find any other tracks not present. Is this a dead u7000? Proper brain stuck now.


So this is obviously a liquid damaged board you got. In most cases no battery recognized is a dead SMC and U7000. Did you test with a good battery? Yours could have died in the fire with the other board. Also the battery indicator can cause issues, disconnect it to be sure.


Thanks Duke, I think your right, it does seem so.. I'm going with dead, I tested with two working original batteries. Only had a fan, dc port and battery connected too.
Probably best off doing an eBay return at this point. It cost me $675AU!


One last go...
r5281 is 3.4v r5280 is .5v
i don't have a working oscilloscope to know if pins 2 of r5280 and r5281 are doing what they are supposed to do right now either.

Changed u7000 r5281 and r5280. Something is fucking up the data lines.