Bed heating unreliable.
Hello everyone!
Sorry to bother but I have an issue with my heated bed. Since yesterday I had 2 prints fail because of thermal runaway at the heated bed. I disassembled the bed, and checked everything just like here: http://help.prusa3d.com/mk2-heatbed/heatbed-not-reaching-temp
Without any issue. The resistance, the voltage, everything is fine. I've had my printer since march and never experienced any issues before especially nothing like this. Since everything seemed fine according to the support page I just reassembled everything and tried again. It worked at first but failed after some hour and a half, again due to thermal runaway. So I decided to just print the first couple of layers with the heated bed turned on since I printed this part with PLA anyway so it should work. But now it does not heat up at all and I got the "Bed preheat error". I also noticed now, that the LED on the bed does not turn on while the LED on the RamBo board does. So I think that there might be some loose connection or something similar, right?
Would it be possible that it is in the bed itself, even though there are no obvious damages? The wires really seem fine, too, as do the soldering pads and I double checked every single connection. I would appreciate any help or ideas on how to fix this.
EDIT: Sorry, I thought I should mention that I tried to wiggle the wires now while preheating. That doesn't do anything though, I had hoped the LED might flash or something, indicating a broken wire.
Many thanks,
Flo
Re: Bed heating unreliable.
My heater wires fractured due to flexing. I have rwplaced them and back in business again
Regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
Re: Bed heating unreliable.
No bother 🙂
What is your print and bed temp? and fan %?
I had a thermal runaway issue recently, I heated the bed at 80 deg C, nozzle temp of 245 deg C and fan speed of 100%. This combination made the bed cool too much. If I am not mistaken thermal runaway kicks in if a temp (nozzle or bed?) has a temp difference of at least 15 deg C for ... seconds
Could be you are running into this issue?
Re: Bed heating unreliable.
Don't try & run anything as It sounds like you have the same problem as me..
The Heat bed connector on the Rambo board has totally burnt out, taking out the 15A fuse, melting the plastic on both the board & free connector, and damaging the board tracks etc...
I'm looking into replacing the connector, but I suspect I'll have to get a new board (I wonder how long the guarantee period is ??) 👿
Re: Bed heating unreliable.
I'm looking into replacing the connector
Not a good idea. Best to leave the existing connector in place and solder the wires directly onto the board. It's very easy to damage what's left of the tracks when removing the connector.
Or solder tails onto the board and get some Wago connectors: http://global.wago.com/en/products/product-catalog/terminal-blocks-connectors/installation-connectors/compact-splicing-connectors-all-conductor-types-222-series/index.jsp (which is what I have done on one printer).
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Bed heating unreliable.
My heat bed is dead.
It warms everywhere but in the middle and the selftest fails as the thermistor measure the temperature in the middle.
Do you know where we can purchase an original MK42 bed ?
I can't see it on the Prusa Website.
Thank you
Re: Bed heating unreliable.
Beds are available here: http://shop.prusa3d.com/en/mk2-spare-parts/119-heatbed-mk42-assembly-.html
If you don't have access, ask "Live Chat" to let you in.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Bed heating unreliable.
Sorry folks. I did not get any notification about your responses, so I didn't really bother to check the thread until now.
Don't try & run anything as It sounds like you have the same problem as me..
The Heat bed connector on the Rambo board has totally burnt out, taking out the 15A fuse, melting the plastic on both the board & free connector, and damaging the board tracks etc...
I'm looking into replacing the connector, but I suspect I'll have to get a new board (I wonder how long the guarantee period is ??) 👿
Oh, yeah you are right. I do have the same problem, I just thought it was a screw terminal rather than a plug (I have like the worst memory ever). I just unplugged it and it was burnt/deformed. Thanks! Would have taken me an eternity to figure that out.
I'm looking into replacing the connector
Not a good idea. Best to leave the existing connector in place and solder the wires directly onto the board. It's very easy to damage what's left of the tracks when removing the connector.
Or solder tails onto the board and get some Wago connectors: http://global.wago.com/en/products/product-catalog/terminal-blocks-connectors/installation-connectors/compact-splicing-connectors-all-conductor-types-222-series/index.jsp (which is what I have done on one printer).
Peter
I think I'm going to try this. I need to install the MMU anyway so I'll just do it in one run. Thanks for the help, I really appreciate it.
Not directed at you, but to be honest, I'm very disappointed that this happened after just 6 months...
Re: Bed heating unreliable.
Not directed at you, but to be honest, I'm very disappointed that this happened after just 6 months...
Well, I believe that the "official" line on this is that you must have made a mistake when plugging the cable in or with cable management...
But it's also happened to me after about 9 months - and I know I did everything correctly (Mk1, where the problem was a lot worse and it was a known problem). I also had to replace the cable because the one supplied with my Mk1 was too lightweight and it broke internally a couple of inches outside the controller box - melted the plastic sheathing.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…