PS2 boots to menu, disc spins,trying to boot, stops black screen. V4 DMS4 lite

[Osirls]

Hello
I had my V4 PS2 working with my DMS4 lite, but then i changed some pot settings on the laser and now when i boot backup dvds, after the ps2 menu appears, and the dvd boots, it stops spinning before the playstation2 logo appears, and i get a black screen.
I tried putting back the pot settings but it still does the same thing.
With DVD movies i get the rsod (please insert ps1 or ps2 disc)

I have checked all my points again, checked all of the PS# fuses and the F1 fuse, and can play Original PS2 and PS1 discs, and backup ps1 discs.

What could this be from, pot to high/low? Bad soldering?
If anyone has any ideas, id be greatful to hear them.

Thank you,
Osiris

[Osirls]

Hmm.. ive had another look tonight, finding that fiddling with the white ribbon cable coming from the laser makes backup ps2 games sometimes work.. This could be because i have moved the P/O wires also, but im pretty sure they are soldered well enough.
I cant keep it working though, everytime i try to reassemble the same symptons return.

[uns97]

DMS modchips are not supported here. Go to their site for help.

regards, Stephen