820-2915 running slow on battery

[PhilipC]

no liquid damage, just suddenly stopped according to customer

It will run fine on a genuine charger but after about 2 mins of unplugging the charger the machine will slow down with 100% cpu usage
System detects and charges the battery also info comes up in the about>more info
It passes EFI asd and OS asd throws up an error

Battery test (test#31) -Unconsumed Battery capacity test
ERROR -- 255 [Uknown result-code 0xff] -- TEST FAILED

This is a replacement battery as I thought the original battery was at fault and have since then thrown away the original battery.
Checked current sense resistors and r7005 all measure fine.

If I remove the battery and plug it back in it will start then after 5 seconds go off. After that it will start normally

And when it boots (charger plugged in) right at the end of the loading screen it glitches out then comes back and continues loading

 

[larossmann]

The glitching out is normal because the video drivers for this model are buggy junk in later OS. That's unrelated.

This must be failing something else in ASD. If you check the temp sensors in hardware monitor in EFI ASD, do they all read right?

 

[dukefawks]

Let ASD loop on the sensor tests a while. Also check VD0R VP0R in hardware profile to see if they read weird.

 

[PhilipC]

looping sensor test now, VP0R 11.92v cant seem to find VD0R

All the sensors look to be measuring ok in hardware profile

 

[PhilipC]

looped and hour each OS and EFI, with and without battery

No sensors fail or look weird. The slowing down of the machine is noticeable in OS asd when plugged in it take 19seconds to complete the sensor tests unplugged goes up to 60 seconds. The slowing down starts 20seconds after unplugging the charger

 

[dukefawks]

VD0R should be there, Q5310 feeds that. Check again.

 

[PhilipC]

This is weird the only voltage sensors are VC0C VG0C VN0C VP0R. Just to double check this is with ASD EFI 3S144

 

[PhilipC]

I dont know if its relevant but EFI ASD takes 5mins on "Search for hardware to run tests"

 

[dukefawks]

I just check on a working machine here and VD0R is indeed missing. So this proves ASD is not testing all sensors that are present. I would check Q5310 and also SMC area for corrosion.

 

[PhilipC]

Thanks for confirming, No signs of any corrosion in those areas or anywhere on the board.

 

[dukefawks]

I have no other ideas besides an SMC issue. Could be ME region issue maybe. For test try this BIOS, preferably on a donor chip, so you don't mess up the original.
https://drive.google.com/open?id=0ByfhQ_x0v-tZZDhfeUNPTFRpSHc

 

[PhilipC]

Is SMC reflow worth a try? Will try that bios can I use a chip from a 2850?

 

[PhilipC]

Scratch that they're, not even the same size. I'll have to use the existing chip and back it up. Worth a shot?

 

[PhilipC]

Tried Clean ME region, everything still the same

 

[dukefawks]

I am out of ideas here. Could try SMC, but not much hope.

 

[PhilipC]

tried relow on the smc twice still the same, this is weird. Once it goes slow even if i plug the charger back in it still stays slow

 

[dukefawks]

Have you verified with a known good ORIGINAL battery? That Chinese garbage should never be used. 13" battery will also work for testing.

 

[PhilipC]

Only the original battery that the machine came with, will try with a known good 13" battery

 

[TCRScircuit]

I had one that was super super slow and was missing ACOK.. Wouldn't charge either. Ended up being the 6259.

 

[PhilipC]

I left it running without a battery and eventually it also slowed down, checked ACOK measured ok.