Sony PCV-J200 - Manual (Page 60)

VAIO® System Reference Manual 48
Memory Module (DIMM) Connectors
Both sides of each Dual Inline Memory Module (DIMM) look very
similar. The side with pin 1 has a small "1" to the left of pin 1. Position a
DIMM correctly in the DIMM connector (a small triangle on the
connector indicates pin 1).
DI
MM1
DI
MM2
1 1 1 1
Memory module (DIMM)
Indicates pin 1