Saturn not reading discs, strange issue

[rsonic]

Hello

I recently got a Pal Saturn that doesn't read disks.

After testing it, I noticed some unusual behaviour:

-When booting, the Saturn polygons animation play normally, but when the Sega Saturn logo appears, the console hangs and remain on the title screen for like a minute (no noises come from the disc drive).

-After that, the Bios finally boot, but directly with the "checking disc format" (there is no disc in the tray of course). During the check, the laser doesn't move and you can't hear the usual noise of the laser.

-the console seems to NOT recognize when the tray is open (no sound in bios) nor when the tray is closed, with and without a disc inserted (so you can't trigger the "checking disc format" manually basically).

-In the Bios if you press the RESET, you get a black screen. From here you can only turn off the console and turn on again, with the same cycle that repeat hangs for a minute in the title logo, "checking the disc format" with the emply tray etc.

Do you know what it could be and how I can solve the issue?

Thank you

[rsonic]

forgot to say it's a Model 2 Pal.

[rsonic]

Update on the issue:

I tried to switch the laser from another laser assembly (since they are both the Optima 6).
The issue remain identical.

1-Long boot sequence (but animation logo plays normally)
2-At startup, there is again the Checking disc format, that remain for like 30 seconds.
3-the console recognize the lid open and closed now (I fixed this, the rpevious owner tied the sensor to do some swap disc trick).
4-In Bios pressing the Reset button, bring a black screen that last 30 seconds, after that the console finally resets.
5-During the black screen, opening the lid reset instantly the console instead.

In the end I tried to:

-swap lasers from another laser assembly
-swap the ribbon cable of the disc drive-mother board
-tried the new laser assembly (don't work, maybe it's incomaptible with this model)

What else can I try?

Thank you