Thanks. Navmans seem even more defective, I have some that won't boot or in reboot loops - they say non-volatile ram is the problem. I have discovered a modern USB-3 adapter pumping out up to 3 amps breathed life into many GPS's. I presume the battery or a capacitor on board has high internal resistance, breaking the boot cycle, but the extra current allows it to recover. Saved a few TT's that way.There are many fake 2amp adapters that barely deliver one, so don't believe ratings.