Advantech PPC-A84/A120-X5X user manual Modules can only fit into a socket one way

You can install anywhere from 16 MB to 128 MB of on-board DRAM memory using 16, 32, 64 or 128 MB 144-pin SODIMM (Small Outline Dual In-line Memory Modules).

The procedure for installing SODIMM appears below. Please follow these steps carefully.

1.Ensure that all power supplies to the system are switched Off.

2.Slip the SODIMM into the socket at a 45 degree angle and carefully fit the bottom of the card against the connectors.

3.Gently push the SODIMM into a perpendicular position until the clips on the ends of the SODIMM sockets snap into place.

4.Check to ensure that the SODIMM is correctly seated and all connector contacts touch. The SODIMM should not move around in its socket.

Note:	The modules can only fit into a socket one way and
	their gold pins must point down into the SODIMM
	socket.

2 6 PPC-A84/A120 User's Manual