Try disconnecting the battery, disconnecting the USB cable, powering it on to discharge any caps, and then boot it with just the USB as power supply? Battery might be getting soft...
73, Willie N1JBJ
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On Sep 25, 2021, at 7:24 AM, Al Holt <grovekid2@...> wrote:
Hello all,
I'd had this nanoVNA-H for a few years, h/w v.3.4, and it's had this startup trouble for a long time. At power on, the screen lights up, a blank screen flickers as if trying to boot and after ~30 seconds goes dark.
For a long time I've been able to get it to boot by repeatedly flicking power switch off and on. Researching the trouble on this forum I have found I can attach external power to USB port and then after ~30 seconds pull the connector and it will boot.
Symptoms were there with the original firmware. I've updated it to v.1.0.64. Battery voltage is 4.16 volts. I've read about a troublesome IC or cap, but I can't find those on my board, a blue PCB that looks official.
When it does boot, it works well enough.
What the best course of action? I wouldn't mind a larger screen, but I'm reluctant about purchasing a -H4 model if I can get this one to reliably start.
Thanks!
--Al
WD4AH
