Fuse burned
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So yeah that PSU is not fit for use anymore, as you lost all warranty on it and its now a liability. If anything happens, you will be personally held responsible.
Can you show the bed wires on the bed side?
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@oliof
by account I did not install a mosfet -
@sgk If your heater were rated at less than 15A (i.e. 360W on 24V, or 180W on 12V) you would not have needed an external mosfet. And if it would pull more, it would just have blown the fuse unless you get to very high wattage/resistances, i.e. a short.
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@oliof ha ok i have always had this 24v 350w bed
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@sgk  -
@sgk that would be fine, especially if you PID tuned it. Also it looks like the discoloration is on the VIN side, not the V- side where the PWM switching happens. This on board mosfet looks fine
but we might need a higher resolution picture of it.
Since this looks like a machine that ran well for a while, my money is still on an issue with the wiring on the bed side causing a short.
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@sgk yes, on your bed side picture you can see lack of strain relief, and already broken strands of the wiring.
This machine is a fire hazard.
Replace PSU and bed, and get someone with good knowledge of electrics and electronics to make sure the replacement is set up safely. Also make sure to add strain relief anywhere moving wires are attached to something (bed, hotend, and ideally board side as well).
You will also need to replace the control board as I do not believe its safe to continue using it even if you replaced the melted fuse.
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@sgk replace the control board ?
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@sgk this
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@sgk when I but another fuse it burns the fuse every time
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- Replace PSU, Control Board, Bed Heater.
- Do not modify the PSU.
- Redo wiring safely.
- Add strain relief.
- Do not modify the PSU.
You really got saved by that fuse but just so.
<>RatRig V-Minion Fly Super5Pro RRF<> V-Core 3.1 IDEX k*****r <> RatRig V-Minion SKR 2 Marlin<>
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@oliof ok thank you
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@sgk DO NOT POWER ON THIS PSU, BOARD, BED HEATER AGAIN.
You are putting your life at risk.
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can you advise me for power supply and bed please
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no, I'm telling you find someone close to you with th appropriate skill set. I can't give you advice over the internet and check that you follow it.
I'm not giving you further advice on this matter besides what I already did. Keep that machine disconnected and powered down, replace the obviously broken parts, and get help doing so at your place.
<>RatRig V-Minion Fly Super5Pro RRF<> V-Core 3.1 IDEX k*****r <> RatRig V-Minion SKR 2 Marlin<>
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@oliof ok thank you
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@sgk from the photo I see that the board is a clone Duet, not a genuine one. The fact that the bed fuse melted before burning out makes me suspect that it was made using 1oz copper top and bottom, instead of the 2oz (double thickness) copper that genuine Duets use in order to handle high bed heater currents.
From the photo of the back of the board, it looks to me that there is a metal washer shorting against the end pin of the Z motor connector. That's probably why the Z motor connector is burned. We supply nylon washers with genuine Duets to avoid this happening.
