I have a Duet Ethernet that I believe is about 1-1/2 years old on a CORE XY printer. It has run flawlessly up until a week ago when the board quit printing mid print during the night. Lights were on, fan off and a communication error on the web interface. I restarted the board and it worked fine for a few days and then quit mid print again. I was in the room when it happened this time and the blue, red, green lights on the borad were blinking on/off with what sounded like a relay trying to latch. Again restarting the board the issue cleared. On the next print, within 30 minutes, a "Warning: High Temperature on Driver 2" appeared and the Z axis stepper and the left side XY stepper stopped moving while the extruder and right side XY kept moving.
I don't know if this is of any help but here is the M122 log while in the fault. Restarting the board again clears the fault but I don't trust that it will function for long.
=== Diagnostics ===
Used output buffers: 3 of 32 (9 max)
=== Platform ===
RepRapFirmware for Duet Ethernet version 1.19 running on Duet Ethernet 1.0
Board ID: 08DGM-95BNL-MGPSN-6JKDG-3SN6T-TKYVZ
Static ram used: 17684
Dynamic ram used: 95892
Recycled dynamic ram: 1112
Stack ram used: 1136 current, 8344 maximum
Never used ram: 8040
Last reset 02:41:15 ago, cause: power up
Last software reset reason: User, spinning module GCodes, available RAM 11976 bytes (slot 0)
Software reset code 0x0003, HFSR 0x00000000, CFSR 0x00000000, ICSR 0x00400000, BFAR 0xe000ed38, SP 0xffffffff
Error status: 0
Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 0.0ms
MCU temperature: min 37.4, current 38.4, max 44.6
Supply voltage: min 9.0, current 23.5, max 23.9, under voltage events: 2, over voltage events: 0
Driver 0: standstill
Driver 1: stalled standstill
Driver 2: standstill
Driver 3: stalled standstill
Driver 4: standstill
Date/time: 2019-03-20 23:03:18
Slowest main loop (seconds): 0.230408; fastest: 0.000000
=== Move ===
MaxReps: 3, StepErrors: 0, FreeDm: 240, MinFreeDm 150, MaxWait: 123496ms, Underruns: 0, 0
Scheduled moves: 2, completed moves: 2
Bed compensation in use: none
Bed probe heights: 0.000 0.000 0.000 0.000 0.000
=== Heat ===
Bed heater = 0, chamber heater = -1
Heater 0 is on, I-accum = 0.1
Heater 1 is on, I-accum = 0.8
=== GCodes ===
Segments left: 0
Stack records: 1 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s) 0
file is idle in state(s) 0
serial is idle in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
=== Network ===
State: 5
HTTP sessions: 1 of 8
Responder states: HTTP(1) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)