Tom Tom XL - is it unfixable?

[None of your business]

Obviously an old device. My mother's. She has always tended to leave it charging during use.
5 days ago she plugged it in using the USB cable into a 3-way port with an iPad also connected. The device started up fine, plotted a route and lasted for about half an hour then suddenly without warning went off.
The iPad had charged about 20% in that time so the charger/cigarette lighter was working.

The device was hot. When we tried to turn it on the TomTom screen would appear then disappear almost at once.

We left it and navigated to and around Paris by map. Thank goodness we have them.

Anyway forward to today. OH has plugged the satnav into his laptop and updated it. It will now turn on and stay on. If we head up to the garage (with it plugged in using the cigarette charger in a power pack - it's like having one of the original mobile phone) it will find satellites. You can set a route and then within a few minutes the satellites all disappear. The device gets warm.

Is there anything to do to fix it or has it been overheated whilst charging it with the iPad?

 

[dhn]

The iPad should not be providing so much power that the device overheats. Sounds like something else is going on. Maybe the battery beginning to die in it?