@gloomyandy is today's big winner!
G29 S1 ; Set Units to Millimeters
When this is commented out it works fine.
RatRig's RepRap firmware page here has this listed. It's the cause of all the issues I've been having. I've contacted them and it should hopefully be fixed soon.
Thank you all soo much for the help! I seriously love this community 
@phaedrux said in Board caught on fire:
Wow that is quite spectacular failure.
When and where did you purchase the Duet?
Filastruder in July 2021
@oliof said in Board caught on fire:
Are you running Klipper by chance?
No I am not
@gixxerfast said in Board caught on fire:
Wow, spectacular. Not the sort of thing I'd want to happen to my printer.
Please take this the right way as not trying to cast any shadow on the description here at all only trying to understand would could cause such a major breakdown..
But I would like to ask if you perhaps had heat sinks attached on the driver chips? I see that you have one on the MCU and that usually runs much cooler than the drivers in my experience.
I did have heat sinks on the drivers but they were the tall skinny ones and I was very sure there
wasn't any metal or anything on the bottom. They were fully "covered" on the bottom.
@dc42 said in Board caught on fire:
@nightlonk42 what power supply are you using? The only things I can think of that are likely to blow multiple drivers at the same time in such a spectacular fashion is reversed power supply polarity, or excessive voltage from the PSU.
I'm using a 24V Meanwell and it's been working fine up until now. I did just check the voltage and I'm actually undervolted by a small amount (23.7). Also double checked the polarity and it's fine. It's been working up until last night perfectly.
I also have a other few devices plugged into the PSU (Buck converter for the Pi4, power to Toolboard) and those are fine as well.
@phaedrux said in Duet mini+ failing to heat hotend:
@nightlonk42 said in Duet mini+ failing to heat hotend:
I wiped the override, ran another PID, saved the values in config file, restarted the board, then did a M500.
You must send M500 immediately after the PID tuning completed, not after restarting the board.
I'll try that. One moment
(Sorry about the weirdness on the post above. I was trying to upload all the files and it marked it as spam and won't let me edit it anymore)
M303 T0 S205 is what I'm using for the hotend.
I wiped the override, ran another PID, saved the values in config file, restarted the board, then did a M500.
[19_1625425463232_tpre0.g](Uploading 100%) [18_1625425463232_tpost0.g](Uploading 100%) [17_1625425463232_tfree0.g](Uploading 100%) [16_1625425463231_stop.g](Uploading 100%) [15_1625425463231_sleep.g](Uploading 100%) [14_1625425463231_retractprobe.g](Uploading 100%) [13_1625425463231_resume.g](Uploading 100%) [12_1625425463230_pause.g](Uploading 100%) [11_1625425463230_homez.g](Uploading 100%) [10_1625425463230_homey.g](Uploading 100%) [9_1625425463230_homex.g](Uploading 100%) [8_1625425463230_homeall.g](Uploading 100%) [7_1625425463229_heightmap.csv](Uploading 100%) [6_1625425463229_dwc-settings.json](Uploading 100%) [5_1625425463229_DuetWiFiServer.bin](Uploading 100%) [4_1625425463229_deployprobe.g](Uploading 100%) [3_1625425463228_config-override.g](Uploading 100%) [2_1625425463228_config.g.bak](Uploading 100%) [1_1625425463228_config.g](Uploading 100%) [0_1625425463228_bed.g](Uploading 100%)
; config-override.g file generated in response to M500 at 2021-07-04 14:58
; This is a system-generated file - do not edit
; Heater model parameters
M307 H0 R0.374 C501.700:501.700 D18.02 S1.00 V28.0 B0 I0
M307 H1 R3.255 C211.500:80.300 D6.31 S1.00 V28.3 B0 I0
; Workplace coordinates
G10 L2 P1 X0.00 Y0.00 Z0.00
G10 L2 P2 X0.00 Y0.00 Z0.00
G10 L2 P3 X0.00 Y0.00 Z0.00
G10 L2 P4 X0.00 Y0.00 Z0.00
G10 L2 P5 X0.00 Y0.00 Z0.00
G10 L2 P6 X0.00 Y0.00 Z0.00
G10 L2 P7 X0.00 Y0.00 Z0.00
G10 L2 P8 X0.00 Y0.00 Z0.00
G10 L2 P9 X0.00 Y0.00 Z0.00@phaedrux said in Duet mini+ failing to heat hotend:
@nightlonk42 said in Duet mini+ failing to heat hotend:
M563 P0 S"Hemera" D0 H1 F0:2
Are fans 0 and 2 both part cooling fans? Your fan definition says that fan2 is a cpu fan. So maybe you should change F0:2 to just F0.
Can you try tuning the hotend with M303 H1 S205 instead of T0?
@nightlonk42 said in Duet mini+ failing to heat hotend:
Supply voltage: min 27.9, current 28.0, max 28.1,
Also I think you may be over volting your heaters
That did it! I'm not sure if it was the CPU fan setting or running it with H1 but it's working as expected now.
Thank you so much! This was driving me crazy for days now!!!