It originally did not turn on.

After hours of diagnostics I have narrowed it down to.

Turns on with cmos backup battery removed. But also main battery removed. Voltage reading on battery show 3.04 v so that seems good.

Gives error msg of " 0251: System Cmos Checksum Bad

(also) Real Time clock error.

After adjusting settings, time & saving. It will turn on and restart. (with or without battery) Until I pull the power cord and then try to start it.

Then, no matter how long I disconnect the power, how many times I press the power button ( tried the 10x trick then hold for 30seconds)

Will absolutely not boot with cmos battery connected after its had its time set proper.

The battery did charge and holds a charge. It will not boot from main battery alone with cmos disconnected either. But once you have it booted from power plug without cmos and then put in battery and pull power plug.

It will stay on an utlize the battery just fine.

I have flashed the bios to the latest 2.79 via using bootable cd image.

In the process I have done a complete teardown reassembly of this thing. Removing all componenets one by one.

Things that I have tried.

*Disconnecting the webcam.

*Reseating the CPU and reapplying thermal paste.

*Swapping memory sticks with higher rated ram and testing separate memory banks in isolation

*leaving components disconnectedand reconnecting  one by one and reconnecting

I guess the only thing I haven't tried is booting it with keyboard completely disconnected, but then not sure how to power it on without keyboard power button.

Anyone have any ideas as the t430i is

*confirmed to charge main battery.

*Boots without cmos.

*Boots from ac adapter only but will work after plug is pulled

Confirmed cmos voltage of 3.03 confirmed ac adapter voltage of 20v.

Just to be 100% sure, replaced it with a new cmos battery reading 3.26. Issue persists

Seems that this issue also affects t420 t530 e532 T530 X260 from the searching and reading I've done. 

Anyone have any ideas or suggestions ?