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Prusa i3 a pro. Ribbon cable melting

Posted: Tue May 23, 2017 7:36 am
by peterelkjaer123
Hello,

I resently purchased a prusa i3 a pro. Now the 30 pin ribbon cable between the control box and printer has started showing signs of heat damages on the insulation.
As far as I can see the 30 pin cable is supplying power for the hotend and heatbed. Is that correct? If this is the case, is the cable then too poorly dimentioned for that kind of current draw?

Furthermore i can't get the heatbed above 70 degrees. Is there by any chance any heavier ribbon cables on the market that can stand that kind of power draw?

Kind regards and best wishes of a nice day
Peter

Re: Prusa i3 a pro. Ribbon cable melting

Posted: Thu May 25, 2017 3:34 am
by Joemac2013
Hmmm... must be a poor connection somewhere. Consider opening the box and inspecting each connection point. The cable connectors need to be inspected, making sure the ribbon cable is seated firmly down on the base of the connector.

Also make sure your power supply is Set To 117 vac ... now the good news is I have 3 of these up and running and there is no problem like that appearing up. In fact these machines are pretty reliable. I think they are too noisy! Get three of them running , along with PCs to run them and it sounds like some kind of power plant! The fan in the controller box seems to do a good job of keeping the power supply and electronics cool, but it is loud.....

I would like to design a controller system that had no fans, like tablets have no fan....

Re: Prusa i3 a pro. Ribbon cable melting

Posted: Thu May 25, 2017 4:18 am
by peterelkjaer123
Hi,
Thanks for the advice. I have already checked all connections and they seems to be ok. My plan is to make a wuick and dirty fix by wirering the heatbed directly to the control board until Geeetechs supportteam gets back to me with a solution to the problem.

Regarding the voltage setting i think i will leave it at 230 since i live i Denmark :lol:

You are absolutely right about the noice level from these printers. I started out with an GT prusa i3 pro and the noice level is almost as bad on that machine. I have been thinking about doing the Apple trick and use the entire body of the control box as a giant heatsink, but i guess it will take quite an amount of ingeneering to make the heat travel from the ICs to the body. What are your thoughts on making a fanless controlbox?

Once again thank you for your input :)

Re: Prusa i3 a pro. Ribbon cable melting

Posted: Thu May 25, 2017 4:57 am
by Joemac2013
I was thinking that an old fashioned linear supply, and redesigned stepper drivers...

It will be a ways off but someday! I like the mechanics of this model.