I bought one of the original NanoVNAs not long afte rthay came out, and initially it worked OK. Put it away and hadn't used in for perhaps nearly a year.
When I came to use it today, obvs. the battery needed charging, but the touchscreen ignores most of my presses, and those it does interpret it gets wrong then goes into a huff
The manual slider doesn't respond
Don't think I'll ever get one again, no matter how much better the new ones are.
Not sure whether to put a hammer through it or dismantle to see what's inside.
A hammer would be more satisfying.
Meanwhile, the job I wanted it for, the DG8SAQ did the job perfectly, with a much nicer display. Just meant taking the laptop and the 'SAQ outside - so wasn't so convenient.