I can recommend you to remove everything, clean and look with magnifying lens for solder splatters.
That's all you can do. One short circuit from solder splatter is enough to keep it from booting.
Also, you don't need DMS4 or Crystalchip anymore. Why bother installing it if you can just use Free MC Boot and Open PS2 Loader ?
There's even ESR you can use with discs if your laser is still working for DVDs.
If I were to install a DMS4 on one of my PS2s it would be only to attempt dumping the Toxic OS core component for looking how it works. Nothing else.
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...)