Exploding Fuse

Hi
I received an Ormerod RepRapPro 2 for Christmas and I have been putting it together every weekend since. I have just got to the stage in the instructions for testing the heaters. I had connected the power cable but when I switched it on at the socket the fuse immediately exploded, the rocker switch on the PSU was in the off position, tripping the RCD for all the sockets in the house. I reset the RCD in the house, and rebooted the computer, now though the Duet is no longer detected by Windows. So whatever went wrong appears to have fried the circuit board, the little led but lights up but that is all.

First of all does anyone know what caused the fuse to explode?
Does anyone know what fuse I need to replace the one that exploded?
Is there anyway to resurrect the Duet board?

I must say that I am not impressed with this 3D printer, having had broken parts on arrival, missing parts, and cables that were not properly terminated, and after all that now this.

Thanks
John

There is a a short somewhere to the metal enclousure probably ,or near the plug of the power supply. Did you kaption tape the metal below the duet? check that you wired the powersupply and the duet correctly.

You mean the fuse inside the plug? or the house fuse? if you have any metal part of the fuse it should state there what fuse it is i think. i will check mine after my print finishes and tell you what it is.

Thanks for responding Darathy.
I did use the kaption tape below the duet board. Your right I should of been clearer, which fuse. It was the one that is fitted in the IEC socket and mounted to the PSU. I have been checking for shorts as suggested in the instructions with my multi-meter, and correcting any as I built it. I have the metal ends of what remains of the fuse, but they are too badly burned/melted to read anything off of. the Fuse in the 3 pin plug is a 10amp

Sounds to me that the mains wiring between the IEC connector and the PSU is probably incorrect.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I will check the wiring from the IEC connector to the PSU, but surely, the fuse would not of blown until the rocker switch on the IEC connector was flipped if the wiring was incorrect?

Has anyone got any suggestion on how to fix the Duet board?

Quote
Promethus
I will check the wiring from the IEC connector to the PSU, but surely, the fuse would not of blown until the rocker switch on the IEC connector was flipped if the wiring was incorrect?

Good point - and very strange that the fuse blew with the rocker switch off. Does that IEC inlet make the junction between the fuse and the rocker switch available as a connection on the back?

Edited 1 time(s). Last edit at 01/30/2016 05:25PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
Promethus
I will check the wiring from the IEC connector to the PSU, but surely, the fuse would not of blown until the rocker switch on the IEC connector was flipped if the wiring was incorrect?

Has anyone got any suggestion on how to fix the Duet board?

The fuse that is in the IEC rocker switch is a time lag/quick blow mains (240v) type one. You should be able to see the rating upon the metal ends.
That fuse blowing would indicate a problem on the mains side not the 12v output side. If you have replaced it with a correct replacement and it hasn't blown again, it should be fine. As might have just been a weak fuse.

Here is the RRPro documentation [reprappro.com] on communicating with duet which should fix the board.

---

Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

According to the documentation the fuse is a 4 amps only. As the minus of the DC-output is connected with the mains ground I am not sure if a short circuit at the DC-output could kill the fuse, but probably not. Maybe there was a problem with the PSU itself?
Did you check the output voltage? If you only get some low voltage the Duet won't work, but some LEDs could glow.
Can you provide some pictures of your mains connection?

---

Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Quote
Promethus
Hi
I received an Ormerod RepRapPro 2 for Christmas and I have been putting it together every weekend since. I have just got to the stage in the instructions for testing the heaters. I had connected the power cable but when I switched it on at the socket the fuse immediately exploded, the rocker switch on the PSU was in the off position, tripping the RCD for all the sockets in the house. I reset the RCD in the house, and rebooted the computer, now though the Duet is no longer detected by Windows. So whatever went wrong appears to have fried the circuit board, the little led but lights up but that is all.

First of all does anyone know what caused the fuse to explode?
Does anyone know what fuse I need to replace the one that exploded?
Is there anyway to resurrect the Duet board?

I must say that I am not impressed with this 3D printer, having had broken parts on arrival, missing parts, and cables that were not properly terminated, and after all that now this.

Thanks
John

I blew the RCD while assembling my second Ormerod too. It turned out to be because when I pushed the wired socket into the aluminium enclosure, the wires bent in such a way that the earth sheath contacted the neutral pin. This tripped the RCD as soon as an energized mains lead was connected to the Ormerod. Had it contacted the live pin instead, chances are some thermal damage would have occurred before the RCD was tripped. This doesn't really explain why your fuse blew though...

Bart

Quote
bartdietrich
I blew the RCD while assembling my second Ormerod too. It turned out to be because when I pushed the wired socket into the aluminium enclosure, the wires bent in such a way that the earth sheath contacted the neutral pin. This tripped the RCD as soon as an energized mains lead was connected to the Ormerod. Had it contacted the live pin instead, chances are some thermal damage would have occurred before the RCD was tripped. This doesn't really explain why your fuse blew though...

Sorry, but I have to say that: Never assemble or do anything else with the mains connection while the plug is in the socket. Never ever! You risk your life! And you only have one.

---

Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

So I have now taken the Duet housing off to get at the wiring and everything is connected correctly. The side of the IEC connector has been blown out (there is a large hole in it), and there is scorching on the wires and PSU. There is also a bit of the earth sheath that if frayed, but not scorched (sheath has scorching further along), it also wasn't in contact with any of the terminals when I opened it up, so I cannot be sure if this is the cause, or as a result of the explosion (I am still finding bits of fuse and IEC connector half way across the room, it was that violent). I have been though the troubleshooting as suggested by orictosh, and I am not reading the correct voltages for 5V I am getting around 3.4V and for the 3.3V I am getting around 0.5V. So it looks like I am after a new IEC connector, 4amp 240V quick blow fuse, and a new Duet board. Anyone know where I can get the Duet board from now RepRapPro have ceased trading?

Think3dPrint3d, and Replikeo. Replikeo's boards have a high rate of failure, if the feedback on this forum is anything to go by

Why do you think Replikeo has a high failure rate?

---

Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Think3dPrint3D only have the v0.8.5 on their site, which is currently out of stock. Would this version still be compatible with my Omerod 2?

Replikeo have v0.6, but, no offence intended, are they safe to purchase from, do they accept PayPal (I'm not a fan of using card details in offshore stores)?

Thanks
John

I ordered already two Duet 0.6 boards from Replikeo and payed via Paypal. Only the support is a little bit slowly and you have to remember them but that is all.

hint: This Duet version uses 1k resistors instead of 4k7.

---

Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Thanks for the quick response Treito
I am going to pick up a new IEC connector and some fuses from Maplin in about an hour so I can test the board with the 12V supply, to make sure it is not just the USB connector that is dead. If that fails I will order the board this afternoon. My Duet board is v0.6, but came with the 4k7 resistors, oh well, I guess I will just have to change the config file, again.

Photos if anyone is interested:
[goo.gl]

If you buy the 0.8.5v you might have to make your own case ,the holes for the screws are 4mm instead of 3mm on 0.6 and the layout is abit different(ie the hot end goes in from the side and there is no place in the metal enclosure to properly wire it.

otherwise it will work normaly and you will be able to do dual extrusion withought any addons.

Edited 1 time(s). Last edit at 01/31/2016 05:57AM by Darathy.

Quote
Treito
Why do you think Replikeo has a high failure rate?

Chinese based factory. Use cheap parts. Their wiring is just live and neutral and no concept of an earth circuit or using fuses. I seen an extruder that was made in that part of the world and there was a 3 core mains lead going though an unprotected metal hole in the casing and only the live (brown) and neutral(blue) connected. The earth was connected in the plug but not on the metal box. Meaning that if the live touched the metal box it would be become live and shock if touched.

@Promethus
From reading post, I would say the reason for the fuse blowing and the house electrics RCD tripping, was due to the live 240v connection touching the metal duet case.
High voltage with low resistance equals high current flow giving a loud bang

Have you checked the PSU for correct mains voltage settings and output voltages ?

Being careful chop the IEC connector off a disused computer power lead, strip off all 3 wires so you are able to wire directly to the terminals.
Don't power the lead before doing the connection, Don't touch the mains side and power the PSU without anything attached,
then check the output voltage on the DC side.

You need to check that the PSU is working correctly before connecting the new board and parts.
Once you have done this, take the lead you made up and chop the wires flush to the end and cover with electrical tape.
You don't what to leave that lead with bare wires lying around with a 3 pin plug on the other end.

The other reason for this to happen is that everything is a tight squeeze behind the IEC switch and connector and the metal casing. If the mounting point for the switch was a little further out, this would lower the risk

---

Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

Well I got the parts from Maplin. It also appears that the 10amp fuse in the 3 pin plug was also killed. I have taken on your suggestion orictosh, to test the PSU, however I don't like you methodology, chopping of connectors and direct wiring, sounds kinda dangerous to me.

Anyway, I connected the power, no explosion this time, and tested the DC end, which my multi-meter reported as 12.1V which looks right. So I tried connecting the Duet, and powered it up. There was a bit of a smell from the PSU at first, but soon dissipated. After about 2 minutes there was another smell, I could not work out where it was coming from, until I saw a wisp of smoke from the USB connection. I switched it off and started looking around the board with my IR thermometer; the USB connector was at over 40C, there was also another part of the board that was over 60C, a little black component, to the right of the heated bed terminal (I don't know what the component is called)

The new IEC has a proper cover on the back, and I have also covered the DC output cable from the PSU in heatshrink so there should be no more shorts, and I have purchase a new Duet from Replikeo. At least it will get me going, until the v0.8.5s come back in stock.

Quote
Promethus
Well I got the parts from Maplin. It also appears that the 10amp fuse in the 3 pin plug was also killed. I have taken on your suggestion orictosh, to test the PSU, however I don't like you methodology, chopping of connectors and direct wiring, sounds kinda dangerous to me.

It is/was kinda dangerous, that was the reason for the bold comments, as you are dealing with/near 240v mains voltages but it was only a temporary thing to test just the PSU and bypass the IEC rocker switch, without risking the other parts. If you respect mains voltage and understand it, it won't hurt you, if things are badly wired or misunderstood then it will. One reason for moulded plugs was that too many people couldn't wire a 3pin-plug correctly or were colour bind so caused accidents. Which is good thing.

Quote
Promethus
Anyway, I connected the power, no explosion this time, and tested the DC end, which my multi-meter reported as 12.1V which looks right. So I tried connecting the Duet, and powered it up. There was a bit of a smell from the PSU at first, but soon dissipated. After about 2 minutes there was another smell, I could not work out where it was coming from, until I saw a wisp of smoke from the USB connection. I switched it off and started looking around the board with my IR thermometer; the USB connector was at over 40C, there was also another part of the board that was over 60C, a little black component, to the right of the heated bed terminal (I don't know what the component is called)

The new IEC has a proper cover on the back, and I have also covered the DC output cable from the PSU in heatshrink so there should be no more shorts, and I have purchase a new Duet from Replikeo. At least it will get me going, until the v0.8.5s come back in stock.

Seems like the IEC rocker switch that failed wasn't a good one or the correct one and you taken steps to stop the metal parts touching the live parts. The little black component, if it has three legs it could be a voltage regulator taking the 5v from USB down to 3.3v for the processor.

Chris

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Supporting 3D Printers with Parts and Build services.
Printer: Ormerod 2 (528.4) Duel extruder set-up with Aluminium X-Rib, RRPro Firmware v1.11-ch (2016-04-08)

If the USB connector or cable gets hot, that is a sign that you don't have a good connection between the negative output of the PSU and the negative power input terminal of the Duet.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

The initial explosive short was almost certainly a short between live and neutral or live and earth. This must have been after the fuse in the IEC block. As you believe that the switch was off at the time, my guess is that the short was inside the IEC block, either due to a fault in that socket or to pushing the connecting wires inside the block creating a short.

Another possibility however is that the wall plug or IEC socket was wired incorrectly. Swapping the live and earth wires in the plug or IEC socket will lead to that sort of thing for example, and the application of 240V to the chassis and hence negative supply of the Duet can easily fry circuits (it may well find a return path via the USB and connected PC). Incorrect socket wiring should not have had an effect until the switch was turned on, but perhaps the OP was mistaken about the switch position (the markings on mains switches are not consistent and can often be ambiguous).

Dave