Atock extruder, heater keeps shutting down.

possible short in the wiring to the hot end? 

That's all I can think of... check the connections at the resistor point and see if you're touching the block in any way.

cold extrusion prevented

not much help

I'll watch the log closer, see if it says anything else.

Thanks.

That's actually a lot of help - you just have to think about it. If it thinks it is too cold to extrude, one of two things are happening:

1.) The hotend is actually too cold to extrude, which means you either have it set below the minimum temperature, or the heater is not delivering enough heat.
2.) The connection for the thermistor is failing, which results in it thinking it is colder than it is. This can be trouble because it tries to dump heat into the hotend to boost temperature, but if it is reading cooler than actual, you could exceed the maximum temperature rating of the PEEK.

Once you have determined the possible causes for the error, troubleshooting is pretty simple. For example, once you see the error you should try manually pushing filament through the hotend. If it flows, you know it is hot enough.

Number 2 is more likely, because the connecters are not crimped well as 2n2r5 said.

You'll want to run PID Autotune to cut that down:
http://www.soliwiki.com/PID_tuning

Repetier-Host EEPROM Procedure
To start the autotune process we will use the same command as above:
M303 S200 C5

I was able to print for an extended period last night without it tripping off, then when it sat idle between parts, it tripped again, even set on 190C. So, it seems like the filament actually cools the barrel enough to keep it from snaggeling, but idle, it overheats. I'll try that PID Autotune. Thanks.