ProBook 640 G2 Memory Upgrade Problem

[MaxProAndU]

We're experiencing a problem upgrading one of our last ProBook 640 G2's from a single stick of memory to two sticks so we can take advantage of the system's dual channel capabilities. This laptop is docked as a workstation and never sees any mobility.

The one stick of memory our 640 G2 came with is a SK Hynix HMA41GS6AFR8N 8GB 2Rx8 PC4-2133P DDR4-17000 that sits in slot #1. The stick we added in slot #2 is also a SK Hynix HMA41GS6AFR8N that was pulled from another HP laptop. Once added, the laptop has the infamous "3-long-beeps/2-short" indicating a memory problem.

If you remove the original from slot #1 and replace it with the "new" stick, it boots just fine.

If you place the original in slot #2 and the "new" stick in slot #1 we're back to the "3-long-beeps/2-short".

And if you try to only boot from slot #2 you just get the "3-long-beeps/2-short" regardless.

We've tried everything (we believe) that we've been able to find about the "3-long-beeps/2-short" online but with no success. Personally I've been upgrading memory in PCs for 35 years and have never seen anything like this using good sticks. Has anyone else had problems with ProBook 640 G2s? What in the world are we missing?

[MaxProAndU · Accepted solution]

Mystery Solved!

One of the SODIMM pins in slot #2 was misaligned. Got out the sure-point tweezers and led magnifying glass, and with the grace of God, got the pin in place.