Compaq portable 2 memory error displayed on boot

[youno31]

Hi, I recently obtained a Compaq portable 2 which was basically just a pile of parts. I assembled said parts and noticed the memory expansion board was missing, could this explain the memory error displayed at post or is the expansion board exactly that, just add on memory.
I now nothing about the machine and have no manual books either so all advice is appreciated.

Cheers