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Heatbed stopped heating 3dp-12 printer

Posted: June 27th, 2019, 7:07 pm
by Shazam0527
I noticed that the heatbed won't heat now. I moved the cable that plugs into the bed (6 wires) and the temp changed briefly now it won't at all. Looks like one of the wires may have broken inside the insulator cover. What's the easiest way to test a wire for connectivity? I'm an electronics newbie, but I know someone has this answer :)

I'm stuck and can't print until I find that short.

Re: Heatbed stopped heating 3dp-12 printer

Posted: June 27th, 2019, 10:07 pm
by Roberts_Clif
There are 2 Yellow wires connected to +Bed and 2 Black wires connected to -Bed
You have 2 Red wire connected to the (NTC) thermister.

On aluminum hot bed connector pins
Resistance between Pins of two same color yellow or the two same color black is zero as they use two wires to have the ability to carry more current with smaller wire.
The resistance across Pins the yellow wires connected to and Pins the black wires connected to is 2.6 ohms.
The resistance between Pins that the red wire connected to at room temp is 100K ohms (NTC) thermister

Re: Heatbed stopped heating 3dp-12 printer

Posted: July 6th, 2019, 12:34 pm
by Shazam0527
Awesome Roberts_clif! That was exactly what I needed to find it. Now it looks like my first Yellow Wire has broken off at the connector inside the molex (?) connector. Is there a way I can pull that metal tab out to recrimp/solder it back into place? If not, how can I replace that connect for the heatbed?

Thank you again!

Jonathan

Re: Heatbed stopped heating 3dp-12 printer

Posted: July 6th, 2019, 12:58 pm
by Roberts_Clif
There indeed is a way. IF you look at the connector you can see the silver pins.
If you look very closely you will see a Flap holding the pin in, if you push it down carefully the little flap will push down releasing the pin.
After removing the pin, can restore the flap to the original position using a knife.

This is where the hard part starts, you will have to un-crimp the rear of the pin and reshape it to be re-crimped.
Or using a high temp solder, solder the wire to the pin and replace in the connector.

Or you can purchase another one here

Housing and terminals 6 way
I believe I found some at Jameco and on Ebay

This should make your search so easy now.

Re: Heatbed stopped heating 3dp-12 printer

Posted: July 6th, 2019, 1:21 pm
by Shazam0527
Molex KK got it!! :D Thank you so much! I looked up Molex, but it was giving the traditional computer style ones only. You've been a great help! :)