Man ... Sincerely. Remve the mod, clean all points (mainly all bios points) then clean again. Try it without mod. If it doesn't work then you have trouble.
Seriously, a lot of PS2s die because we accidentally hit the silicon on the RAMBUS memories (the small chips close the Emotion Engine) and crack them. They're as fragile as Athlon cores. Any mechanical stress might crack them and a PS2 w/o ram = black screen or ever worse, no screen at all.
I recently found out that I accidentally killed my japanese V5 this way while trying to install a MI on it. And I think I'm a experienced modder...
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...)