New Lenovo P71 motherboard won't recognize Battery

[nubie]

I got a P71 Motherboard (i7 7700HQ) for my Lenovo P70 so I could run a P3000 video card I had that my Clevo P770DM didn't like (It seems the Clevo likes the P4000 fine).

Machine runs great, but will not recognize the battery. It either says battery 100% no charging, remaining time unknown, or it says 255% Battery not detected, or no battery.

I used the maintenance USB Key to set machine type and Serial and it stopped complaining about that on boot.

I did a BIOS load defaults, and it is up to date so I couldn't reflash the EC or the BIOS from Windows. I downloaded the Power Manager driver and made windows use it for the battery, which it did not do when installed.

I have 170w and 230w power supplies, and the battery works fine in a second P70 I have here.

Is it possible I just have a bad connection or a fault to the Battery communication terminals?

[mon2]

Re: New Lenovo P71 motherboard won't recognize Battery

No, probably the TVS esd diodes on the smbus lines are defective. These parts protect against static charge surges on the battery connector. When they do their job, the part will short to ground.

With care, measure the voltage to ground of each pin on the battery connector. Post each measurement.

Also share a clean but close pic of the battery connector area. Then we can locate the esd diodes...likely a 3 pin device. Even better if you can post or link a schematic.
..

[nubie]

Re: New Lenovo P71 motherboard won't recognize Battery

With care, measure the voltage to ground of each pin on the battery connector. Post each measurement.

The pins 3, 4,5 for SMBus and battery temp are all around 3.5v, in line with this schematic. The laptop is all together at the moment, will have to check the board later.

[mon2]

Re: New Lenovo P71 motherboard won't recognize Battery

SMBUS voltage readings are good - the SCL / SDA lines are not stuck.

For comparison - check the same readings on the working laptop.

The logic boards are identical between the 2 units? You can charge or deplete the battery on the working logic board and the battery gauge properly reports the status? This confirms the battery is ok.

Next would be to inspect the contacts of the battery connector on the logic board. Perhaps an issue with the EC chip that is the SMBUS master = often a 8051 embedded micro controller that communicates with the battery. Maybe needs to be reflashed? Wait on other comments.