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[BUG REPORT] Heating platform stopped heating

Posted: Fri Feb 28, 2014 3:44 am
by fmaurer
My heating platform suddenly stopped heating. I haven't been able to heat it for a print, but everything else still works. The heating goes from 17.6C to 18.3C (max) in 45 minutes, when before it would do the same jump in a few seconds.

I removed the cover and found the culprit. The attached photos reveal the wire going into the platform's heating element is damaged. What's interesting is that there is no damage aroung the wire -- it's as if it were cut. My theory: fatigue of the wire moving back and forth snapped it.

Image
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How can I fix this? I'm experienced in soldering. Replace wire and add some kind of strain relief?

Thank you for any help you can offer!

Re: [BUG REPORT] Heating platform stopped heating

Posted: Fri Feb 28, 2014 4:11 am
by LonV
Yeah, it's all wire fatigue. You can solder it, but it will just break again (and sooner than before). You'll need a replacement cable...I believe the newer cables are designed better.

Re: [BUG REPORT] Heating platform stopped heating

Posted: Fri Feb 28, 2014 9:25 am
by mr6k
This is a weakness of the design and has happened to many. After mine failed and as I mainly use ABS I made a new platform out of a sheet of Acrylic, ABS sticks to tthis at room temperature.

Finally I repaired the heater wires as follows, firstly the original temerature sense wires were still good. So cut the heater wires back close to the plug by the vertical column, I then got some good silicon coated braided wire, as used for electronic meter probes, soldered that to the wires at the plug, routed them out through a gap at the back of the horizontal column and around to the heater block, squeezing them down the side of the platform mount and having cut away the heater leads at this end soldered these external leads to the original heater leads. I made up two clamps to hold these external leads, one at the rear RHS of the horizontal column and one at the rear RHS of the heater block. The only critical part is to get the external cable length correct, long enough to cover the full platform horizontal travel, but not so long that it sags and catches anything when the platform is at the rear.

Am away from my printer at present, will try and post photo early next week.

cheers

Peter

Re: [BUG REPORT] Heating platform stopped heating

Posted: Sun Mar 02, 2014 5:46 pm
by mr6k
psat heater underside lo res.jpg
Underside of UP Plus platform
psat heater underside lo res.jpg (107.81 KiB) Viewed 7670 times
Here is how I repaired my heater cable. It had failed exactly as Fmaurer shows in his photo, heater wires burnt through, thermistor sense wires OK..
i cleanly ccut the heater wires where they had burnt, pulled back the heater wires from the sleeving leaving then attached to the connector, leaving the sense wires in place. I pulled back the other ends of the heater wires and cut them leaving about 1cm on the heater. I then fed the original heater wires from the connector near the vertical column, through a gap at the rear of the platform horizontal column via a sleeve, see photo. I attached, soldered, instrument test cable (flexible fine braid silicon clad cable) to the original heater wires at the back of the printer and sleeved the connections with heat shrink sleevin. I then fed them through a gap close to the heater block, see photo. I then soldered them to the 1cm ends of the original cable at the heater, ensuring they were not touching each other or grounding to any metal. I then covered the soldered connections with nail varnish, to insulate the wires, and let it dry. I printed acable clamp to hold the new wires at the rear of the printer platform column, see photo, and fitted a P clip to the rear RHS edge of the heater block (Drilled & Taped a hole for a screw to hold the P clip.) When doing all this ensure that the new cable is long enough not to strain at the limits of travel and is also not so long as to sage and catch/jam any part of the mechanism.

I have been running with this modification for about 3 weeks and it works fine.

No doubt the thermistor sense wires will eventually fail, if they do I will just add two more wires to this new path. (Such wires could be much thinner as the carry almost no current.

Hope this helps those of you that need to repair your printers .

Re: [BUG REPORT] Heating platform stopped heating

Posted: Tue Feb 09, 2016 12:53 pm
by mr6k
Well, it finally happened. Now the platform temp sensor cable has failed due to excessive bending, just as the platform heater cable did some time ago.
So I applied the same solution. I have rerouted the sensor cable out the back of the printer via silicon flexible cable and back through the underside of the platform. If you look at my original images of the heater cable reroute I have just added 2 much thinner silicon cables the same way. The only other change was to make a new cable clamp at the rear, replacing the yellow one and on a short arm holding the cables back a bit further as with all four cables the platform screws (white ones) were just touching the cables when the platform was fully back. There is now no ribbon cable in the platform "box" to flex or get caught in the belt.
I will post images if anyone needs to see them.


cheers

Peter