Burned Heated Bed Connector

[mbef 0]

I suspected there was something funny when my UM2 (now UM2+) smelled a bit different.

But when I saw some magic smoke coming out of the wires at the back of the heated bed, and then a little sparking, my suspicions were confirmed. Something bad was going down. On close inspection, the big heater power wires were charred to carbon, and on removing the build-plate and bed assembly, the main brown wire (#2) was melted into the connector. The connector is toast - literally.

It has made me think, because we've had a few Temp Sense Error: BED alerts over the years, which get better when you poke the bed wires: wondering if the wires were loose, or whether the connector is up to handling the current (this is a 2013 machine, I recall seeing comments to that effect). I inspected them when we did the UM2+ upgrade in the summer, and they seemed ok then.

I unsoldered the connector, and unfortunately the connector came away with the two thermistor pads - I think the solder wasn't melted properly because the heated bed was acting as a heat-sink, and perhaps they had degraded with heat. Not a total disaster: I think I can solder a wire to the stub ends of the tracks.

But I need to reconnect the four wires to the board. So my questions are:

1. Does anyone know where I can source a replacement connector, please? I've been digging around on RS and Digikey, but I can't see one like it.

OR

2. Are there any standard hacks for this situation? I'm wondering about soldering new wires to the bed PCB, clamping/restraining them to the bed using the existing connector mount screws, and then using a separate connector to affix the supply wires - is that feasible?

OR

3. Am I an idiot who needs to buy a new heated bed?

Edited November 22, 2016 by Guest

[mbef 0]

Actually, let me simplify the question: Does anyone know where I can source a replacement heated bed 4w connector, please?

Thanks!

[Torgeir 242]

Hi mbef,

Maybe you'll need something like this..

http://no.rs-online.com/web/p/pcb-terminal-blocks/3617667/

Check the pitch, the distance between the solder holes..

Just a shot..

Thanks.

Torgeir.

[mbef 0]

Hey Torgeir, thanks for that ... yep, I was looking at those, but I was rather hoping to find the exact connector - that way, I won't have to do too much improvisation around mounting and fixing it. I've become a bit cautious after the smoke and sparks :-)

Cheers,

Mbef

[Waternut13134 1]

If your in the US FBRC8 has the bed parts. I had the same exact thing happen to me and they sent me a new bed and connectors. They told me UM had problems with this so they changed the connection type to push pins.

This is what my connector looked like when I hit it with the FLIR. I was noticing a smell for a few weeks that smelt like wet dog and couldnt find the source until I started seeing smoke.

Edited November 24, 2016 by Guest

[mbef 0]

Just realized I never posted the outcome here. This is what happened:

 

I tried hard to fit ... well, anything ... to the bed. I couldn't source the right connector, as it's supplied with the bed as a complete unit. But the pads that I was trying to connect to were badly frazzled anyway, and gradually the whole area disintegrated; there was nothing stable to solder anything to. Problem was that the whole bed acted as a massive heat-sink, and I couldn't inject enough local heat to control the solder. The thermistor started falling off too...

 

I contacted Creat3D - our original vendor - who were helpful, but in the end I just bought another bed from them, which was quite expensive but was a quick and non-bodged solution. The new bed has a different - far better - style of connector, so I'm glad I did it. The cost is filed under "reasonable wear and tear".