In this week three routerboards have been hanged up! Maybe because of -30°
I was discussing this at MUM and I get the impression Mikrotik will be looking into this further...
If you look up the IC's used on the Routerboard eg processor 79RC32H434-266BC
see http://www.idt.com/products/files/57150 ... 434_ds.pdf
You will find that some of the IC's used are rated "Ta Commercial Ambient Operating Temperature 0 +70 °C" what this means is the specification is guaranteed between these temperatures not that at -1degC the IC starts playing up!
Due to manufacturing variability you may find some IC,s still working down to -30degC plus the heat generated inside the IC helps.
The common way of testing finished products is to pop them in the deep freeze (-25degC) the problem is you could have a batch that keep working during your testing stage and -30degC is a bit extreme.
The way Mikrotik have built there boards is quite normal, in fact the build quality is excellent it's just we want them to work at the north pole and the hottest desert and not cost any more
So how could you get round this problem....
Use product with Ta Industrial Ambient Operating Temperature -40 +85 °C..not a option yet
Add a heater and thermostat in box, if you can get enough power out of POE or run extra cable. I would think the best way is a resistor glued on top of each, of the low power IC's thus minimizing power used and putting it where needed. There are small thermostats (about the size of a 1W resistor) available that cost a couple of Euros.
If the units are not subjected to a high summer temperature a little insulation ether on the IC's (not the processor it will get hot) or around the box, but keep a eye on the temperature!
The processor gives off 1.3 to 1.8 watts, place a small sheet of aluminum touching each of the IC's to transfer some of the heat between them. The metal should touch the IC's as close as possible, have heatsink compound or thermally conductive glue between to help, this could act as a heatsink so may need insulation as well.