You battery is likely bad. Lithium based batteries do not like to be deep discharged. It will kill them. The VNAs have a very small but finite current drain when powered off and need to be occasionally maintenance charged if not used for long periods.
On Thu, 24 Oct 2024 07:21:02 -0700
"Jim Ancona N1ADJ via groups.io" <jim@...> wrote:
I've used my NanoVNA-H4 periodically for several years. Yesterday I charged it, then upgraded the firmware from NanoVNA-H4-SI_20211230 to NanoVNA-H4-SI_20211230. I re-calibrated and started doing some testing with it apparently working fine. I got distracted for a few minutes, and when I checked the screen was black. I powered it off, then back on, but the display only appeared for a second, then went black.
--
73
-Jim
NU0C
Jim Shorney