I just completed a 300+ layer print without a problem

I'm relieved to have found the problem and thanks to everyone who helped with advice.

Now to see what tech support will do for me.

I have sent an email to tech support with the above info. I am racking my brain to figure out if there is anything that I am overlooking.

If a bad reading from the extruder thermistor can cause the errors I've been experiencing, then I can see a situation where a faulty thermistor connection could fade in and out. I've never seen the extruder temp read zero before last night which led me to think it was just another symptom of a communication issue.

The part which stood out to me was that RH would keep going when it would fault out during a print. I would think a fault signal from the printer to RH would pause the job. That was purely an assumption on my part.

I guess I'll see what SD comes back with.

Mike

Nope. RH would be happy to keep sending commands under a 'cold extrusion prevented' situation. I only know because when I was putting together an incomplete printer I ran a print job with no extruder (Slicer settings set to room temperature) and watched the head move around while RH was getting multiple errors.

If a bad reading from the extruder thermistor can cause the errors I've been experiencing, then I can see a situation where a faulty thermistor connection could fade in and out. I've never seen the extruder temp read zero before last night which led me to think it was just another symptom of a communication issue.

The part which stood out to me was that RH would keep going when it would fault out during a print. I would think a fault signal from the printer to RH would pause the job. That was purely an assumption on my part.

I guess I'll see what SD comes back with.

Mike

Anyway, 3 weeks old should be a discussion with tech support, not here.

Ever since I've had it, it would periodically drop communication between the printer and my computer.  If it happened during a print, the printer would stop while RH would fast forward through the rest of the printer commands.  On RH I could manually command the printer to return to home position and it would work, but I couldn't manually move any axis or do anything with the extruder.  When it would do this, the extruder and bed heaters would show that they were on, but the temps would start dropping.  My solution was to disconnect RH, shut power off on the printer and restart my computer.

I've been able to print about 2/3 of a spool of ABS, but it got to the point where I couldn't get through any print that was over 50 layers and then I couldn't get through more than 10 layers before it quit.  It now is to the point where I cannot even get the bed and extruder heated up before it faulted out, much less start a print.  Now the extruder temp shows as 0.00C all the time.  The printer started it's downward spiral a couple days before I was away from home for a week and since I've been back, it has gotten worse. 

When the printer stops responding, I get the message "Printer stopped due to errors" and when I try to use code M999 it will disconnect completely and say it is receiving nothing but errors.  I haven't tried troubleshooting the extruder temp showing as 0 yet because it seems too coincidental to all the other problems I've been experiencing. 

I've tried a different USB cable, a different computer (my normal runs Windows 7, the other I tried was running Windows 8) and every combination of communication settings and still nothing. 

If there is anything else to try, please let me know.  I'm about to pull my hair out...