400C lasers are not suitable for the V1, V2 and V3 units. It might work on the V3 but you will end up breaking the laser flat cable lol.
V4s or newer can use 400C lasers. (very few V4s have mechacon firmware capable of taking HD7 laser so it's safe to say they won't work with HD7s)
V5s or newer can use early HD7 (old with 400B laserchip, what people call R laser) and current HD7s
V3 and older can run with all 400C lasers but the issue is mechanical.
10k (V0) will only work with 400A/B lasers or 400C lasers with old laser chip (white lens AND orange fexible board)
A thing I sugest you to do is test the laser you got from the shop in a newer PS2. If it's running fine then you can try to fit it into a v4 and take the V4 laser (400b) on that V3.
SCPH-10000_GH-001 SCPH-15000_GH-003 SCPH-18000_GH-008 SCPH-30001_GH-005 SCPH-30000_GH-016(V4) SCPH-30001_GH-010(V4)
2xSCPH-10190, 2xSCPH-10350, 2xSCPH-10280
"**** j0 hackers!"
-Sjeep (As seen on TOXIC OS ELF...)