[SOLVED]820-3115 - Can't see battery.

[gcain]

CS laptop needs a new battery, but it can't see any batteries.

Board is practically spotless. In diode mode, SDA is 0.196v and SCL is 0.400v . 17/18 and 20/21 of the U7000 measure okay.

Measure against a working board, SDA should be about 0.400.

We looking at an SMC replacement?

 

[TCRScircuit]

Exact voltage on PPBUS_G3H?

 

[gcain]

PPBus_G3H = 12.25v

 

[gcain]

I replaced U7200 and we have a battery back.

Haven't seen that behaviour with a faulty U7200, or maybe I just forgot.





Edit: After a few minutes the green/orange light is switching every five or ten seconds. Could this be bad soldering.
I looked closely and it seems all the joints are nice.


PPBus is back to 12.25v
I must have disturbed what ever the issue was for a moment. I don't even get an orange light at all any more.

 

[aprendiz]

This could be a bad U7000, bad SMC, corrosion on BIL connector, bad BIL or corrosion under battery connector, first remove BIL and inspect connectors (battery and BIL)-----replace U7000----replace SMC

 

[gcain]

Sorry, I meant U7000.

BIL looks spotless. I have replaced U7000 and everything worked as expected for 10 of 15 minutes then slowly deteriorated back to the original behaviour.

I can swap it again, but would rather not tear through all my U7000s.


Originally when I removed U7000, diode on SDA went back to ~0.400, but now when I remove it, the measurement remains at ~0.200v.

I suspect there is just a short, that I managed to disturb somehow when I first swapped U7000 out.

 

[dukefawks]

Crap under BIL connector or SMC most likely.

 

[gcain]

SMC_RESET_L seems to be floating.

 

[dukefawks]

Define "floating"

 

[gcain]

It seems to be moving up and down freely, as if there is a pull up or pull down resistor missing.

dukefawks I was just looking at this board closely and I noticed the green light appears to be flashing really quickly.

 

[dukefawks]

Crap under SMC or U5010 area.

 

[gcain]

I've already replaced U5010. Just sent a ton of flux under SMC and seems to be working again.

We'll just have to see for how long.

Thanks Duke.


Edit: board is braindead now.
This repair hasn't gone to plan. :'(

 

[JohnB8812]

Replace SMC

 

[gcain]

Just came back to this board.
I ended up running flux under the SMC again and heating until it was dancing around with the air.

Board gets a picture again and charges a battery.

Mark solved please.

 

[2informaticos]

Reball SMC, to avoid future problems...