Hi everyone! I put a dvd disc on my player but there is a "no disc" message on the screen and the disc was not turning. The disc motor checked OK with a digital multimeter. The lens was cleaned with a cotton swab that was wet with alcholhol. I checked the internals but there is no signs of any problem such as loosed wires or burned out component. What are the possible causes to this problem?
Thanks in advance.

 

Since you noticed that the disk motor checked out (I assume you mean it had a voltage across it) and was not turning it is likely the disk motor is faulty.

Good luck finding one; it's probably a custom part. You might be able to find spare parts for it though.

 

I checked the resistance of the disc motor, since turning the motor manually with the power off caused a response to the winding resistance I assumed that the motor winding is ok. My concern is that a "no disc" message is displayed even with a disc placed on the tray. I will try to check the voltage input to the motor. Thanks for giving me that idea.

 

I checked the resistance of the disc motor, since turning the motor manually with the power off caused a response to the winding resistance I assumed that the motor winding is ok. My concern is that a "no disc" message is displayed even with a disc placed on the tray. I will try to check the voltage input to the motor. Thanks for giving me that idea.

The catch/interlock on the lid is probably broken, and it thinks the lid is open.

Or, it could be that the laser is dirty and needs a clean. When the lid is closed, does the laser try and seek? Does it seem like it's trying to find a disc?

And finally make sure you try multiple disks - the disc you use may be faulty. I've had situations like this (where the disc or some component was faulty) and I blamed the whole system.

 

When everything works mechanically but the unit says no disc - it will usually be the laser diode that is dead. No laser light for the electronics to 'see' a disc with.. Common with the cheaper units. Bad diodes, or bad current control on the diode driver. But whatever the cause - its usually the diode has no output causing the no disc display.

 

I cleaned the lens with a cotton bud that was soaked in alcohol. I tried different discs but the problem remains. The lid switch seems to be working as it is indicating if the cover is open . There is a display "loading" but the disc motor is not rotating. I believed you are right that the laser diode is dead since this is a cheap unit. I will try to find a replacement. Thanks everyone for your time and concern.

 

Hello,

If the motor is not running there is a problem with the motor control.
If the laser is not working correctly the motor will run at full speed and can not be controlled, as there is no feedback from he disc.
You will often hear the focus control tick as it is trying to focus on the disc.

Bertus