Thanks,
I turned on logging and got (filtered on Temp):
> 8:04:41.959: T:232.81 /233 B:100.00 /100 B@:148 @:0
> 8:04:43.077: T:233.44 /233 B:100.03 /100 B@:150 @:230
> 8:04:44.176: T:233.44 /233 B:100.00 /100 B@:135 @:0
> 8:04:45.262: T:234.69 /233 B:100.00 /100 B@:154 @:0 <--- TEMP DROPPING FROM HERE
> 8:04:46.366: T:234.38 /233 B:100.00 /100 B@:141 @:0
> 8:04:47.451: T:233.44 /233 B:100.00 /100 B@:153 @:230
> 8:04:48.554: T:233.44 /233 B:100.00 /100 B@:140 @:0
> 8:04:49.658: T:232.50 /233 B:99.97 /100 B@:145 @:230
> 8:04:50.744: T:232.19 /233 B:100.00 /100 B@:152 @:230
> 8:04:51.847: T:231.56 /233 B:100.00 /100 B@:146 @:230
> 8:04:52.950: T:231.25 /233 B:100.00 /100 B@:145 @:230
> 8:04:54.052: T:230.63 /233 B:100.00 /100 B@:145 @:230
> 8:04:55.139: T:228.75 /233 B:99.97 /100 B@:149 @:230
> 8:04:56.242: T:228.00 /233 B:100.00 /100 B@:138 @:230
> 8:04:57.345: T:227.50 /233 B:100.00 /100 B@:144 @:230
> 8:04:58.447: T:227.25 /233 B:100.00 /100 B@:137 @:230
> 8:04:59.534: T:226.50 /233 B:100.00 /100 B@:143 @:230
> 8:05:00.637: T:225.25 /233 B:100.03 /100 B@:138 @:230
> 8:05:01.739: T:224.00 /233 B:100.03 /100 B@:144 @:230
> 8:05:02.826: T:223.25 /233 B:100.00 /100 B@:129 @:230
> 8:05:03.928: T:222.50 /233 B:100.00 /100 B@:147 @:230
> 8:05:05.030: T:221.00 /233 B:100.00 /100 B@:140 @:230
> 8:05:06.134: T:220.25 /233 B:100.00 /100 B@:139 @:230
> 8:05:07.220: T:219.36 /233 B:100.03 /100 B@:134 @:230
> 8:05:08.322: T:218.72 /233 B:100.00 /100 B@:144 @:230
> 8:05:09.426: T:217.23 /233 B:100.00 /100 B@:131 @:230
> 8:05:10.512: T:216.38 /233 B:100.03 /100 B@:132 @:230
> 8:05:11.614: T:215.74 /233 B:100.03 /100 B@:132 @:230
> 8:05:12.718: T:215.11 /233 B:100.03 /100 B@:131 @:230
> 8:05:13.820: T:213.19 /233 B:100.00 /100 B@:135 @:230
> 8:05:14.907: T:212.98 /233 B:100.03 /100 B@:130 @:255
> 8:05:16.010: T:212.34 /233 B:100.03 /100 B@:129 @:255
> 8:05:17.113: T:211.70 /233 B:100.03 /100 B@:135 @:255
> 8:05:18.200: T:210.43 /233 B:100.03 /100 B@:122 @:255
> 8:05:19.304: T:209.32 /233 B:100.00 /100 B@:132 @:255
> 8:05:20.406: T:208.98 /233 B:100.03 /100 B@:127 @:255
> 8:05:21.508: T:207.97 /233 B:100.03 /100 B@:126 @:255
> 8:05:22.598: T:206.95 /233 B:100.03 /100 B@:126 @:255
> 8:05:23.698: T:206.61 /233 B:100.03 /100 B@:119 @:255
> 8:05:24.802: T:205.93 /233 B:100.03 /100 B@:130 @:255
> 8:05:25.888: T:204.75 /233 B:100.03 /100 B@:123 @:255
> 8:05:26.990: T:203.90 /233 B:100.00 /100 B@:128 @:255
> 8:05:29.112: T:-444.00 /0 B:100.03 /0 B@:0 @:0 D0:2
> 8:05:29.181: T:-444.00 /0 B:99.97 /0 B@:0 @:0 D0:2
> 8:05:30.285: T:-444.00 /0 B:99.86 /0 B@:0 @:0 D0:2
> 8:05:31.387: T:-444.00 /0 B:99.83 /0 B@:0 @:0 D0:2
> 8:05:32.490: T:-444.00 /0 B:99.73 /0 B@:0 @:0 D0:2
> 8:05:33.575: T:-444.00 /0 B:99.69 /0 B@:0 @:0 D0:2
> 8:05:34.679: T:-444.00 /0 B:99.62 /0 B@:0 @:0 D0:2
> 8:05:35.782: T:-444.00 /0 B:99.49 /0 B@:0 @:0 D0:2
> 8:05:36.272: T:-444.00 /0 B:99.45 /0 B@:0 @:0 D0:2
> 8:05:27.374: Error:One heater seems decoupled from thermistor - disabling all for safety!
> 8:05:27.374: Error:Temp. raised to slow. Rise = -9.25 after 13079 ms
> 8:05:27.375: Disabling all heaters due to detected sensor defect.
> 8:05:27.375: DebugLevel:14
> 8:05:29.111: RequestStop:
> 8:05:36.273: fatal:Heater/sensor error - Printer stopped and heaters disabled due to this error. Fix error and restart with M999.
So it looks like the temp sensor (thermistor) is ok because its still showing a valid looking temperature, and the hotend heater is not working as the temperature is dropping even though its being commanded to heat.
