Pretty sure that's not right..

I was a bit skeptical of the way the heatedbed is hooked up on my O2, looks like maybe I had good reason to be (though maybe it was just an issue with the wire and not the connection)... Noticed a distinctly different smell in the office while printing, looked over at the printer and saw this.



It appears the bed is still functional, but will need some cleanup. Maybe the wire was damaged inside/at the edge of the crimp. Its a bit hard to tell much at this point for me.

Anyone with suggestions as to how to best rewire this thing so I don't need to bring marshmallows and graham crackers to work?

Edited 1 time(s). Last edit at 03/03/2015 06:04PM by achaz.

Detached the burnt off lead, should have realized the brass screw would have bonded to the solder pad, the whole area easily lifted and spun free of the board leaving a pleasantly acrid crater


This leaves me a little unsure as to whether there is enough left to salvage here and re-use the board or if I need to suck it up and get a new one.

This seems to be a common occurrence on the mk2, get in touch with reprap.

---

Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

More about the problem in this thread:

Dead heated bed
[forums.reprap.org]

Erik

Hi achaz

Sorry you've having problems with your bed. See my advice in the other thread here [forums.reprap.org]

However, we have just started shipping a new bed, with soldered-on tab contacts. We had to make some changes to the board, get them made, and test them, which is why it's taken a while to change over. See the '528.4 onwards' tab, here: [reprappro.com]
These are a direct replacement, though require a new MDF insulator and heated bed loom.

Ian
RepRapPro tech support

Quote
droftarts
Hi achaz

Sorry you've having problems with your bed. See my advice in the other thread here [forums.reprap.org]

However, we have just started shipping a new bed, with soldered-on tab contacts. We had to make some changes to the board, get them made, and test them, which is why it's taken a while to change over. See the '528.4 onwards' tab, here: [reprappro.com]
These are a direct replacement, though require a new MDF insulator and heated bed loom.

Ian
RepRapPro tech support

Ah, the newer revision looks like a much better plan. I'll contact you at your support address.

Thanks everyone for the quick responses

Hi Ian
I`m in South Africa how can I get the replacement bed.... as my unit that I bought 3 months ago did the same...
Tx Ben

Had the same problem with mine as most of the pad was left I stripped the cable back removed what was left of the brass screws poked the cable through the hole and soldered the cables directly to the bed. The led dosnt work on mine now because of the damage to the pad. Has been working fine like this for a while now and have done some 13hr + prints with it like this. If I need to remove the bed a can just undo the connections at the duet

BenBB

We'll replace this under warranty. This is the text we normally send out to customers who have this problem:

Sorry you've had problems with your heated bed. We've had a number of reports of failure of this style of heated bed. Usually, it's due to poor connections overheating. Unfortunately, it's not always obvious what causes the problem; it can be the brass screw was not soldered sufficiently, the nuts holding the wiring loom were loose, the crimp on the end of the wire was not well-connected, or the wiring was not secure, and allowed to 'hinge' at the connection, so loosening it or fatiguing the wires. The outcome, however, is clear; that a poor connection of the heated loom to the bed creates heat, and burns out the connection. This is not a short circuit; the connection fails. This should mean that it fails 'safe', and the voltage is disconnected, though it is often accompanied by some burning.

This has led us to produce a new version, with soldered-on tabs; see the '528.4 onwards' tab, here: [reprappro.com]
This is a much simpler and more robust connection, though it meant redesigning the heated bed. This heated bed PCB is a direct replacement, but requires a new MDF insulator and heated bed loom. I am happy to send these parts to you, under warranty.

Alternatively, if the solder pads on the heated bed PCB are still okay, and if you have the facilities and skill, probably the quickest fix/alternative mounting is to solder the ends of the bed loom onto the PCB, like we do with the Mendel: [reprappro.com]

Send me an email, to support@reprappro.com , with a brief description of the problem, and perhaps a link to this thread. Please send me your invoice number if you ordered your kit direct from us, or if you ordered from RS Components or other distributor, as we don't have access to their customer database, please send me your full name and address, and a copy of your invoice (pdf is fine) as proof of purchase.

Ian
RepRapPro tech support