I have a SCPH-30004 V3 Pal model, not modified, never opened, which has problems reading the disks.

I opened the console, checked the laser, which did not have any problems reading, but at some points the disks, stopped reading, without strange behaviour of the laser.

I replaced the laser, with new lasers, which showed exactly the same problems at the same moments.

I had 1 demo disk, which offered me the choice to select a language.
At that point, normally I would see the flags and colors, for each language.

With this console, I did not see the flags, only the text.

What do you think could be the problem here ?
And how to solve this ?