Duet Wifi: Bed Heater stopped working
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I have been using my Duet Wifi for many years, but the bed heater faulted in the middle of a print. Since then, no current gets applied anymore to the bed heater.
I do not see anything burnt, but as it is a Duet Wifi, it does not have a replaceable fuse for the bed heater shown in the Duet 2 Wifi Schematic.My Powersupply is 24V and the heatbed is also 24V. When I connect Vin+ and Vin- to the bed heater, the bed gets heated as expected.
What can I do now?
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@CoolM8 Most likely the bed MOSFET has failed on the Duet (2) WiFi. If there's no replaceable fuse, it just means that it's an older board version, before v1.04 (the board has a version number on it). Post a picture of that part of the Duet, it may be obvious if the MOSFET has failed. See https://docs.duet3d.com/en/User_manual/Troubleshooting/Parts#heater-mosfets for replacement, if possible.
Otherwise, you may be able to drive the headed bed using a Solid State Relay from spare output pin. Depending on the switching voltage of the SSR, you could use a spare hot end heater output, fan output, or an output on the expansion header (these are 3.3V), as the bed heater output isn't working. See https://docs.duet3d.com/User_manual/Connecting_hardware/Heaters_bed#bed-heater-driven-using-a-solid-state-relay
Ian
