T430 does BIOS setup but won't boot - fails memory test

[epk]

I've received a bunch of T430 to set up as part of a donation drive. Most of them were working fine, and I reinstalled the OS and some apps and sent them on their way, but one of them is giving me trouble.

* It will not boot, neither from the HDD nor from a verified-bootable USB flash drive (which worked with the other T430s).
* It does run the BIOS setup utility fine.
* It runs the Lenovo diagnostics fine,
* It passes the short CPU test, the motherboard test, optical drive test and storage test. Haven't run the long CPU test yet.
* It FAILS the short Memory test and fails many of the long memory tests, e.g. "Advanced Integrity", "Bit High", "Bit Low"

My questions:

* Is it _with certainly_ a problem with the SODIMM, or could it be the motherboard?
* If I get another SODIMM, what are my chances of getting the machine to work?

[RealBlackStuff]

Could very well be a RAM problem.
To test, take 1 module out, then try to boot.
Try it in the other slot.
Do the same with the other module.
Also, to compare, test some from the other machines that work fine.

[dr_st]

There is never 100% certainty, but it is overwhelmingly likely to be a RAM issue.

Like RBS suggested, try to swap in memory from another device for testing, since you have many working good ones.

[epk]

Well, I opened the back plate - but only saw a single SODIMM. Removing it, the memory size drops to 4 GB - but the tests still fail.

How can I remove the rest of the memory? If I could do that, I'd put the SODIMM back and see if this one is in working order.

[RealBlackStuff]

Get the T430 manual from the HMM link above.
There is a second RAM module under the keyboard!

[epk]

Well, I DDG'ed a video about removing the keyboard, found the second module, replaced it with the easily-removable module, and - voila! Laptop works

But I installed Linux Lite on it, since with 4 GB I think it needs a lightweight newbie-oriented OS. Was also thinking of AntiX, but that seemed a bit extreme for a machine from 2013.

[RealBlackStuff]

Don't forget that T430 can take up to 2x8=16GB RAM!