Smoke from heated bed

Hi all,
A bit worrying- I turned the printer bed to 57 degrees, and smoke gently started curling from the left hand side power connection of the heated bed.
Now there are black bits, and the solder is hot enough to flow if I poke it with tweezers.
LED was still on.
Underneath, the solder connector to the nut has gone very brown and burnt the tips of my fingers.

Not good. Luckily I was around and noticed quickly

I could buy a new heated bed, but is the bed likely to be the source of the problem? Or is there something else I should look at?

Ormerod 2, standard heated bed, Duet 0.6.

Many thanks.
Still slightly shocked..

Edited 1 time(s). Last edit at 01/22/2018 02:51PM by gwild.

Early Ormerod 2s had a problem with the bed heater because they used screws to transfer the power from one side to the other, which wasn't satisfactory. Later ones used spade terminals soldered to the bed. If yours has 2 screws for the power connections instead of looking like the one pictured in the "528.4 onwards" tab at [reprappro.com], you have the old version.

Edited 1 time(s). Last edit at 01/22/2018 05:08PM 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].

Hi dc42,
You're right, I have the old style heated bed. Presumably the screws don't have enough surface area to transfer sufficient power?

Can you suggest where I might obtain the newer version of the heated bed for the Ormerod 2? [reprapltd.com] doesn't seem to carry them.

thanks!

I had the same problem with the same type of bed as yours. Instead of replacing the bed I soldered the power cables directly to the pads on top passing the cables up through the screw holes. Have been using it like this for a few years with no problems. Only disadvantage is that I cant disconnect the power cables from the bed, this isnt such a big problem as I can just disconnect from the duet end if I need to remove it.

Is there any way to replace the Ormerod 1 heatbed (with ribbon cable) with the Ormerod 2 heatbed (with all its cables)?

I have been using the Ormerod for 3 years now, but was never a fan of that ribbon cable and thin thermistor wires ...

The ribbon cable is very reliable, so I don't see any reason to replace it as long as you are using a Duet 0.6

I replaced the Duet 0.6 in my Ormerod by a Duet 0.8.5 recently. The 0.8.5 doesn't have the ribbon cable connector, so I had to replace the bed heater wires. I used thick highly-flexible loudspeaker wire for them. I kept 2 of the ribbon cables conductors for the thermistor.

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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
dc42
The ribbon cable is very reliable, so I don't see any reason to replace it as long as you are using a Duet 0.6

I highly agree, never did fail on my two Ormerods

Quote

I replaced the Duet 0.6 in my Ormerod by a Duet 0.8.5 recently. The 0.8.5 doesn't have the ribbon cable connector, so I had to replace the bed heater wires. I used thick highly-flexible loudspeaker wire for them. I kept 2 of the ribbon cables conductors for the thermistor.

Erik

Thanks all. After I recovered from my slight shock, I soldered on the wires and all seems ok for now.
I'm very glad that the heated bed wasn't damaged, nor did my house burn down!

Quote
ormerod168

Quote
dc42
The ribbon cable is very reliable, so I don't see any reason to replace it as long as you are using a Duet 0.6

I highly agree, never did fail on my two Ormerods

eh, I had a break in the ribbon thermistor cable, so had to connect the thermistor to the 2 pins located on the side of the ribbon cable pins.