Heated Bed - Replacing the connector

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Your heated bed cable look like this after smelling something burning?

HeadBedBad.png

If so its time to upgrade your headed bed cabling to something a bit safer and more 'rigid'.

The guide below shows how to manually upgrade the cabling.

If you would prefer a plug and play option, Laser Weld Design has created a set of adapters that glue/epoxy into the rigidboard and heated bed connectors and then allow a locking cable to be put in between. Check it out in the shop at www.lwd3d.com under heated bed cable upgrade kit located here... [1]See a picture of the cable here... [2]


The steps in general

Materials needed

* this screw terminal from Pololu.com.
* 48" 18 AWG or 14 AWG silicon jacket highflex wire (2 x 24" pieces) - this can be locally sourced from a hobby shop that sells electric RC cars.
* 48" 24/26 AWG wire (you can use ribbon cable from IDE hard drive connectors).
* 1 2 pin 1mm pitch male header pin.
* 1 2 pin Dupont female connector with crimp pins or 1 2 pin JST connector with crimp pins.


Remove the old connector from the PCB board

Before removing the old connector, use a multimeter to check the resistance of your board. This way you can confirm nothing is wrong after you're done with the process.

This requires some patience and persistence. It is best to use a solder sucker like [this] to get the solder off so you can remove the connector without the use of much force. It might require that you pull each pin from the board separately while heating up the solder. When you are done you must ensure that each pin hole a) has all solder removed (e.g. you can see through it) and b) is not shorted with any other pin holes on the board. Double check both sides of the board and visually inspect this - leaving short someplace will in fact damage your controller, the PCB, and/or the thermistor on the PCB.

You can also use a heat gun to heat all of the pins simultaneously. Pull on the connector with pliers while heating the pins from the other side, and the entire connector will then come out all at once. It may help to remove some of the solder with a solder sucker using the above method. If you choose to use a heat gun, be sure to be careful to not damage the LED or resistor next to the connector.

Connect the male header pin to pin holes under the 0 on the board

The two pin holes beneath this 0 are PIN's 1 & 2 which connect to the thermistor. You should be able to visually trace these pin holes to the thermistor in the middle of the PCB. Once you have soldered the pins to these check the resistance of these pins - ensure they are around 100K at room temperature. Put your finger on the thermistor and watch the resistance change if you are extra worried. Also double check to ensure that no solder has made its way to the other pin holes on the PCB.


Connect the screw terminal

This can be tricky - you need it to bridge the two rows of pin holes. So it will look a bit odd and might require some modification to the pins on the connector. However once done there should be continuity between the pin holes on the same row and screw in port on the connector. It is important at this stage that no solder had bridged between the rows of pins - this will cause a short and the board will not heat up. Also pay attention to which terminal port is connected to the positive and negative pins - the one toward the edge of the board is positive, the one toward the inside of the board is negative. Mark the terminal with a fine point sharpie.


Connect the wires

Connect the wires to your board, the BYE-BYE, or you can directly solder these wires to your original wires (if you do this, keep in mind you must solder the one 18/14 AWG wire to 4 of the original wires). Make sure you are correct in your polarity when soldering these wires!!! I am purposely being vague on this step - as your implementation will vary based upon what board you are using and your direct needs.

Check the continuity between the two terminals after soldering the new connector on. The standard bed should read around 3.6 to 4.0 ohms, but it's better to check yours before unsoldering the original connector. If the resistance is basically 0, you have a short; if it's infinite, you have broken a lead.

Some Photos

You can see some photos of this modification here (using the front loaded screw terminals)

William Eades' solution

He was the trailblazer here! https://plus.google.com/u/0/113622903310463735827/posts/RHZQvmuGyPm


Mike Johnson's solution

HeatBedVerticalTerminal.png


Mike Peters' solution

Very Elegant copper connectors

Full Tutorial on DropBox

Johnny Linden's connector solution

For the RigidBoard's connector

Peter Stoneham's Hard Wire solution

Remove offending plug and socket and Hard Wire ribbon cable