Duet 3 6HC v1.01 MCU Temp fluctuations- Board unusable

[leewaa]

Hi there,

I am in the process of setting up the board but have not gotten very far. I managed to update the firmware of both SBC and the board itself.

The MCU temperature reading however, is constantly fluctuating between 30 and 100 Degrees C. Sometimes it is stable after start up, sometimes not.

With this comes

• constant driver over temperature error messages (when unstable).
• Sometimes it will all start up fine, no errors, status is "idle"
• Sometimes the SBC will start up fine, but will not connect or discover the duet 3.

I have a 120mm fan blowing constant cool air to the underside of the board, and room temperature is around 20-22 Degrees.

It seems like something is fried on the board or what could be causing such a fluctuating temperature read out ?

M22 Diagnostic shows (when it was in a stable state):

M122
=== Diagnostics ===
RepRapFirmware for Duet 3 MB6HC version 3.2 running on Duet 3 MB6HC v1.01 or later (SBC mode)
Board ID: 08DJM-956BA-NA3TJ-6J1DL-3S86Q-9T9QT
Used output buffers: 1 of 40 (10 max)
=== RTOS ===
Static ram: 149788
Dynamic ram: 61196 of which 0 recycled
Never used RAM 147848, free system stack 191 words
Tasks: Linux(ready,135) HEAT(blocked,353) CanReceiv(blocked,927) CanSender(blocked,371) CanClock(blocked,354) TMC(blocked,53) MAIN(running,1277) IDLE(ready,19)
Owned mutexes: HTTP(MAIN)
=== Platform ===
Last reset 00:00:39 ago, cause: power up
Last software reset details not available
Error status: 0x00
Aux0 errors 0,0,0
Aux1 errors 0,0,0
MCU temperature: min 31.1, current 35.7, max 61.6
Supply voltage: min 23.9, current 23.9, max 38.3, under voltage events: 0, over voltage events: 0, power good: yes
12V rail voltage: min 12.0, current 12.1, max 19.4, under voltage events: 0
Driver 0: position 0, standstill, reads 25848, writes 11 timeouts 0, SG min/max 0/0
Driver 1: position 0, standstill, reads 25848, writes 11 timeouts 0, SG min/max 0/0
Driver 2: position 0, standstill, reads 25848, writes 11 timeouts 0, SG min/max 0/0
Driver 3: position 0, standstill, reads 25848, writes 11 timeouts 0, SG min/max 0/0
Driver 4: position 0, standstill, reads 25848, writes 11 timeouts 0, SG min/max 0/0
Driver 5: position 0, standstill, reads 25848, writes 11 timeouts 0, SG min/max 0/0
Date/time: 2021-01-25 10:25:08
Slowest loop: 0.32ms; fastest: 0.04ms
=== Storage ===
Free file entries: 10
SD card 0 not detected, interface speed: 37.5MBytes/sec
SD card longest read time 0.0ms, write time 0.0ms, max retries 0
=== Move ===
DMs created 125, maxWait 0ms, bed compensation in use: none, comp offset 0.000
=== MainDDARing ===
Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== AuxDDARing ===
Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters = -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamberHeaters = -1 -1 -1 -1
=== GCodes ===
Segments left: 0
Movement lock held by null
HTTP* is doing "M122" in state(s) 0
Telnet is idle in state(s) 0
File is idle in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger* is idle in state(s) 0
Queue is idle in state(s) 0
LCD is idle in state(s) 0
SBC is idle in state(s) 0
Daemon is idle in state(s) 0
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
Code queue is empty.
=== CAN ===
Messages queued 0, send timeouts 8, received 0, lost 0, longest wait 0ms for reply type 0, free buffers 48
=== SBC interface ===
State: 4, failed transfers: 0
Last transfer: 1ms ago
RX/TX seq numbers: 723/723
SPI underruns 0, overruns 0
Number of disconnects: 0, IAP RAM available 0x2c8a8
Buffer RX/TX: 0/0-0
=== Duet Control Server ===
Duet Control Server v3.2.0
Code buffer space: 4096
Configured SPI speed: 8000000 Hz
Full transfers per second: 35.98
Maximum length of RX/TX data transfers: 2556/244
 

Any help is much appreciated.

[leewaa]

Ok I think I found the issue. I had initially powered the Raspberry Pi from the duet 3. Then I read its recommended to use an extra PSU in some cases so I then powered them separately. However I did not adjust the jumpers on the board to accommodate for this. I have now adjusted it so that only the INT 5v EN jumper is wired in.

Now I have a constant temperature read out of the MCU and the SBC connects to the board every-time.