At work, I bought 40 panel-PC's (these: http://www.advantech.com/products/5a93b96b-91d6-4a66-b738-db5c65a85a38/utc-510d/mod_121eb06c-38fb-406a-9da3-9433caefd38f), and had someone to build a wooden case around them, with around 15-20cm opening in the bottom, slightly tilted.
Ubuntu 14.04 is supported, which I installed on all of them. Defaulted BIOS-settings. Stripped down the Ubuntu desktop version and tried as well a minimal server version (with no real server stuff running), both only to start Chrome, Firefox or Chromium in fullscreen upon startup, loading an internal web appliation with http(s) and a websockets connection. No keyboard nor mouse connected, just RJ45 and power.
The problem is: several setups die with no reasons at all - they just hang, the clock stops, totally non-responsive, without e.g stuff emitted from websockets. The only way to get them back on track is switching the power off and on again. Different setup every day, totally random, around 5-10 per day, with or without a browser at startup, just idle'ing (I turned off the screensavers, power saving stuff and all the updates to not "disturb" the running system). Installed apport, checked system messages - nothing.
As I am seriously run out of ideas, I need some more aspects regarding this -- how can I continue from here on? I sent two machines to the manufacturer as well to have them check stuff, but want to hunt this down in parallel.
Thanks in advance!