Sorry for this massive necrobump, but I'm having a similar issue here, just got a network adapter and a Maxtor hard drive, 320GB, the model seems to be D33019 and I saw it in the compatibility list.
Network Adapter is official Sony, used.
I plug in the HDD and I can CLEARLY hear it spinning down as soon as the PS2 menu opens, so it's not working. It works fine on PC. I read that this could hint at incompatible hard drive, but it doesn't seem to me like it is incompatible?
Could it be the Network Adapter? The IDE and power port are rather wobbly, but I noticed no issues on closer inspection (seems to be meant to be that wobbly).
Network Adapter does fit rather easily and softly into socket, maybe it is worn out (PS2 had never had a Network Adapter connected to it before).
Any ideas? IS it the HD or the NA or both? Gotta figure out what to send back and replace.
Thanks!