My second one also broke again after almost 2 years... I took the liberty of taking the appliance apart this time. The fault was the same for both - the toothbrush didn't react to anything. When I opened the housing, it quickly became clear that water damage was the cause. Now at least I can use the "battery" as a rechargeable battery ;) Make sure you buy the warranty extension!
Unfortunately, when certain parts are defective, repair is so time-consuming and expensive that a new device is the easier way. Of course, we understand the displeasure about such a procedure. We also experience this time and again in warranty/defect cases.
I have been using the Sonicare Diamond Clean series for 6 years - I am now on my 3rd defect, one of which was replaced by Philipps. The company's attitude to these incidents is unbelievable: 3x this product has stopped working after 23 to 25 months. The advice of the support is very simple - buy the warranty extension as well, the toothbrush cannot be repaired. To that extent, I was offered a 25% discount code - but I have to buy a new unit.
This is a high-end product! However, the company doesn't give a ... The company doesn't give a damn about environmental protection and only knows how to respond to the objection that the battery is an environmental burden: just buy a new one, this time with an extended warranty.