PS2 SCPH-50003A (v9?)CD\DVD problem.

I've got this PS2 yesterday from a friend that wasn't using it(he is now into PC gaming and he stopped using the PS2) along with a Socom game (Socom Navy Seals) which he told me that it sucks.
I took the game out and kept it,installed my old FMCB card and tried my ESR patched games on it (which are pristine,hardly any scratches on them)and,from 4 games,only one worked. (Crazy Taxi,DVD convert)

Any ideas why the rest of the games don't work?The laser in it is a Sanyo HD7.(even though I would have expected a KHS-400C or 400R)
This PS2 has run ONLY original (silver)discs previously.

 

could be as simple as a dirty lens or rails/gears that are dry...............


use a Q-tip and Isopropyl Alcohol for the lens and White Lithium Grease or Silicone Grease for the rails/gears

 

Tried that,and games still don't work.
Also,should I do the Romeo fix on it?
Some discs I have are a bit scratched (PES 2013 is scratched right at the end of the data)but some are as new as they were the day I got them.(example is the Crazy Taxi DVD convert disc I have)

 

Well,I fixed the problem:
Installed a old V9 board with the LA chip shot,taped the DVD door switch (on the spindle)so the PS2 knows the tray is closed,and it runs games from USB pendrive.
Now it is my secondary system,as it got replaced with a 39003 v7 PS2 which works better than my defunct 39004.