I have a strange intermittent wifi problem. I've tried this on my Pi 3 and my Pi Zero W, they both have the same problem. I've tried sudo apt-get update, sudo apt-get dist-upgrade, rpi-update, everything is up to date. I'm running both of these headless - connecting via PuTTY. My connections over wi...

I've got a spare pi, and the SD card works fine with that.

Alas, waiting a week to see if the pi would recover didn't work.

Likewise, powering the pi via the ground and 5v pins didn't work either - same symptoms (PWR LED on, ACT LED not on)...

I have an UBEC: I'm pretty sure it is one of these: http://www.hobbyking.com/hobbyking/store/__4319__TURNIGY_3A_UBEC_w_Noise_Reduction.html - from ebay: http://www.ebay.co.uk/itm/180773848790?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 At first I powered it was 4 alkaline AAs. My multimeter r...