Don't mount F407 vertically...
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I've installed a ~300W bed heater to the F407 and started PID tuning. I watched the voltage on the DWC screen and was surprised it didn't drop (at all)
At around 55°C a bad smell arose and I killed the PSU immediately.
Although the bed has 2.6(ish) Ohm resistance, which equates to 222W only, the bed heater got too hot and the weight of the heatsink pulled it off the PCB
Before, I've tested the bed heater on a Duet2WiFi and it didn't show any signs of stress.
I'm not impressed... -
@o_lampe I know there have been complaints of a similar thing around the CDYv2.
I'm pretty sure the outputs on those are rated to 10 amp, which is lower than the 18 amp on the duet range of boards.
I would suggest the outputs on the F407 have a similar rating at that it's best to use an external MOSFET. -
What bed heater voltage were you running?
- At 12 Volts, 300 Watts is 25 Amps which is too high.
- At 24 Volts, 300 Watts is 12 Amps which is on the edge according to @jay_s_uk
(I don't know what a 407 board even is, so this is probably little help to you, but maybe for others that bump into this thread and have less experience than you do.)
SeemeCNC Rostock Max V3 converted to V3.2 with a Duet2 Ethernet Firmware 3.2 and SE300
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@alankilian here's the RRF info pages https://teamgloomy.github.io/fly_407zg_general.html
And here's the GitHub page with the schematic https://github.com/FLYmaker/FLYF407ZG/tree/master/picture -
@alankilian said in Don't mount F407 vertically...:
At 24 Volts, 300 Watts is 12 Amps which is on the edge according to @jay_s_uk
My cheap multimeter read 2.6Ohm, which would lead to less than 10Amps @220W. (probably not very accurate reading)
@jay_s_uk
IMHO a bed-Mosfet should be oversized to run 24/7 reliably.
The replacement you kindly offered will have the same problem, unless I can upgrade the FET. (will try it on my board first, you don't have to send anything yet).
If it fails, an external MOSFet would work from an extruder heater, too.
