I have two PS2's both model ps2 SCPH-39001. One has the KHS-400C and other has KHS-400R.
The one with 400c laser, the lasers bad.
The one with 400R laser is good but the CPU kept having solder joints crack and I reflowed it 3 times but its finally went.
So I swapped the whole drive with the 400R laser into the the other system and the laser act like crap. It takes longer to read and It makes a high pitch noise when first reads disc. Backup games cut scenes stutter. I used Lens changer and it still has no improvement.
I tried changing lens voltage and adjust the white gear and not much changes. So i reverted them back to original spot.
I cant figure it out why it acts like crap the 400R laser worked great was quite and read games fast but i swapped it into the other system and act crappy.
Thanks for any help.