Before doing anything else, check to see if you can push the charging cable any further into the jack. The designer of the One made the jack unusually deep so it wouldn’t fall off the cable. This also means that sometimes users don’t push the cable all the way in, resulting in the stethoscope not being charged or not being charged completely.
Next, try connecting the charger to a different power source to determine if that is the issue. If you’re confident the charger is connected to a functioning power source and the cable is fully engaged, it is likely the charger, cable or stethoscope is faulty and should be repaired. Contact us to find out how to send your device, as well as the charger and charging cable, to us for repair. This service is free-of-charge under warranty.