PCB Bed Heater Failure

  • I'm replacing all of my PCB bed heaters now because I've had a second printer which was fine initially but has since developed a short to the Aluminium heat spreader, which was enough to over heat the weakish positive feed to the heater on the (both later itteration with white connectors) V0.6. Thankfully caught both at the medicinal smell stage as the PCB overheats but boards still usable if you feed from a different posative feed from the PSU.

    Am I just unlucky or should there be general advice to replace these?

    I'm adding MOSFETs to protect the v0.6 & v0.8.5 boards a little more, and making adding fuses easy.

  • Those white connectors are kind of known problem makers. They are just not rated to current the heater uses. General advise is to unsolder that connector and solder wires to heater directly.

  • The white connectors comment was regarding the duets. Earlier ones had header pins only for steppers and limit switches rather than the white snap in connectors. Reason I mentioned this was because I think there was an issue woth early Duet v0.6 boards having a design fault with weak posative traces to the heater connector.

  • The failure isn't anything todo with the connection of the wires to the board, it's the traces contacting the heat spreader or bolts in two ot more places and shorting through the spreader. I do deburr the heat spreader and ensure the heater isn't shorting to the bolts or plate during assembly. These shorts have occurred in use.

  • Ohh, i see, my misunderstanding.

  • No worries, I thought after I wrote that it may have reada bit agressive. Not intentional just rattling of thought process!

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