I bought in the 2008 a GO720T refurbished
I noticed that when I was shaking the device, I could hear a "Dling" just like there was a free nut inside device.
I didn't had the time to get the device to the service (I bought it in another country.)
I noticed some freeze of the device any now and then.
Now I would like to open the device to change the battery and discover where is this "nut".
Is there a kind of manual on how to safely open the TT GO720 ?