Now he has failed at one time, because of the following: The battery runs out (see pictures)!
The inserted special 1.5V battery (alkaline RAM cell) has been discontinued and has the contacts in the battery compartment as far corroded that the alarm clock did not work anymore. By scraping the crystals, clean it with alcohol and rub the contacts with a cotton swab with WD40, the alarm goes again. However, I have now used an ordinary 1.5V battery and taped the solar module. Those who still have the battery in it, should check regularly to see if it runs out already. I will not use this battery, thus not yet produced more corrosion.
Buy I would no longer Quantys product.