The PS2 cannot talk to the HDD properly it seems ... check the HD combo connections to the network adapter chip ( the black square chip close the spots you solder the connect copper flatcable) one or more might not been connected properly and the PS2 keeps trying to talk to the HDD without success ...
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...)