Version 1, 2 and 3 = 10 Screws at base of PS2 (see screw diagram below)
USA SCPH 30001, Serial Number begins with U1 = Version 1
USA SCPH 30001, Serial Number begins with U0 = Version 2
USA SCPH 30001, Serial Number begins with U1, Date Code 1A = Version 3
USA SCPH 30001, Serial Number begins with U2, Date Code 1A = Version 3
USA SCPH 30001, Serial Number begins with U2, Date Code 0D = Version 3

Version 4 (with electrical warning stamped on the bottom) = 8 Screws at base of PS2
USA SCPH 30001, Serial Number begins with U0, Date Code 1C = Version 4
USA SCPH 30001, Serial Number begins with U1 Date Code 1C = Version 4
USA SCPH 30001, Serial Number begins with U2 Date Code 1C = Version 4
USA SCPH 30001, Serial Number begins with U3 Date Code 1B = Version 4
USA SCPH 30001, Serial Number begins with U4 = Version 4
USA SCPH 30001, Serial Number begins with U5 Date Code 1C = Version 4
USA SCPH 35001, GT3 Edition = Version 4

Version note: All SCPH 35001 and V4 with a date code of 1a or 1b are Phoenix/Messiah-compatible.

Version 5 (with electrical warning stamped on the bottom) - There are 2 Motherboards for the SCPH 30001R
USA SCPH 30001, Serial Number begins with U1 Date Code 1D = Version 5
USA SCPH 30001, Serial Number begins with U3 Date Code 1D = Version 5
USA SCPH 30001R Version 5 Motherboard

Version 7- SCPH 39001 (all)