The message "NO PLAY" on your Grundig GDV 120 DVD player means that the device is unable to read the inserted disc. According to the GDV 120 manual, the most common cause is that the disc has been inserted with the label facing down instead of up. Please check this position immediately and reinsert the disc correctly with the printed label facing up.
If the message persists after correctly positioning the disc, gently clean it with a soft cloth, starting from the center and moving outward. Also, ensure that the type of disc is compatible with your player: the GDV 120 accepts DVD-Video, Video-CD, Audio-CD, and CD-R, in diameters of 8 cm and 12 cm. Check that there are no marks, dust, or scratches obstructing the reading surface.
Next, test with another disc that you know works to determine if the problem lies with the player or the original disc. If another disc plays correctly, the original disc is likely damaged or incompatible. If the problem persists with multiple discs, proceed to the next step.
Perform a complete restart of the player: turn off the device using the ON/OFF button, unplug the power cable from the electrical outlet for 2 to 3 minutes, then plug it back in and turn it on. This procedure resets the electronic circuits of the player and often resolves temporary malfunctions.
If the "NO PLAY" message still appears, the issue may stem from the semiconductor laser (wavelength 650 nm) of the player or an internal malfunction. You can try cleaning the laser with a standard commercial cleaning disc, but be careful: do not use any other solvent (benzene, regular detergent). If these solutions do not resolve the issue, professional technical intervention will be necessary.