Hi,

Your no disc error can be a DIY like the following steps.
Assuming that the disc is good.
1.Clean the lens. - Sometimes because of dust the lens can't read any disc. Try clean the lens by soft cotton buds. Be careful while doing this.

I've suspect that you have a dirty lens,below are just for your guide.
2.Replace the ribbon - Check the ribbon connected to the lens from the main board for scratch, damage. Once it has an open line then of course the lens can't read the disc. Also try to erase the contact by pencil eraser. If you've done the steps above and the symptoms still there then the next step requires you a little knowledge in soldering technique and reading the ohmmeter.
3.Check the motor - Check the motor that spin the disc with an ohmmeter. You can test it using the ohmmeter (x1) even it is connected on the lens assembly.Good motor - reading should be fairly high and it will spin. Bad motor- reading will drop to low resistance and will not spin.
Hint : 50% of my repaired unit the above parts are commonly caused of the problem.
If you confirmed that you have a defective motor then replace it with a new one. Before replacing the new motor you have to check the clearance of the disc holder with the old one. The clearance should be the same as the old because if not the lens will not read the disc if it is too far or too close.
Ifyou already cleaned the lens, and confirmed that the ribbon is good as well as the motor then I've advice you to send it to repair shop because the next step should be done with an expert because it is quite technical diagnosing the fault between the pick-up lens and the main board.

Give a thumbs up if you find it useful.
Have a nice day!

JDVillanueva