My trusty ten year old TT ONE V1 has died (charger failed and took TomTom with it). Now all I get is green light and no switching on. I have tried all the resetting, to no avail, and now have opened the unit up. I have checked that when the mains charger is pugged in the battery voltage rises to 4.2 V, showing it is charging the battery OK.
On the underside of the Power PCB (PCB is marked Glasgow Pwr Pcb Rev 2.0) there is an 8 pin IC, marked 538B and A6204. This is unidentifiable - and unlike any of the ICs other TTs seem to have. Can anyone tell me what IC this is, and also ideas where to look for the failure.

By the way, when the battery is charged up, but the charger is then disconnected, pressing the power button brings the green light on. The onyl way to get the green light off is to reset the device (paperclip in reset hole).

Any help is much appreciated.

Part 2 of my question is what to replace this with if I can't get it going again. I guess the choice is an old style TT from eBay (one that uses TT Home not the new fangled ones that I can't even update using my Linux laptop) or perhaps an old Android phone that I can root and then use to run TT, dedicated to TT. I don't want to root my main phone (An android one). Any other ideas anyone???? I do wish I'd bought another TT when the good easy to use ones were available.