How I installed my heated bed

Dear all,

here a short description of how I installed my heated bed including the changes to PSU and the print bed.

Steps I did:

  1. replacing the PSU with a RSP 500-15:
    The [color=#40BF00]new PSU[/color] gives me more power for this change and future improvements.
    It is bigger than the original PSU and can be installed on the left side facing to the rear side of the printer.
    Two holes can be used, a third hole has to be drilled in the bottom plate of the printer.
    The fourth hole is skipped.

  2. Stripping the print bed:
    First I disassembled the print bed. Meaning stripping down everything of the bed.
    The aluminum plate is used to position the screws on the heated bed
    Keep the glass plate secured for further use.

  3. glueing screws to the new heated bed:
    I put the [color=#00BF00]heated bed[/color] upside down and marked the [color=#00BF00]position of the aluminum[/color] plate to the heated bed.
    So I know where the screws have to be placed.
    Then I put some glue to the plate to place the screws right tin place.
    Additionally, I aligned the aluminum plate over the screws with some distance items, to make sure the position is correct, so the print bed arms will fit after the glue dried.
    Make sure, you do not glue the threads of the screws. This puts you in trouble if you like to use springs for plate adjustment. :slight_smile:

  4. soldering issues
    After the screws are glued to the bed, and everything is dried for use, you should have the solder iron ready.
    The little SMD thermistor is a little tricky and I needed a magnifier to get it done, the wires are easily soldered to the bed.
    I decided to use a four wire [color=#40BF00]connector[/color] to have the possibility to remove the print bed from the printer.
    So the two thermistor wires and the two power wires for the heating are soldered to a connector.

  5. assembling the heated bed:
    That was an easy tasked, and was done in a few minutes.
    The screws are in place, the cork isolation was glued to the heated bed, the wires were soldered correctly.
    Finally, I added some sprints to the screws to have an easy plate leveling.
    Now I place the heated bed to the plate arms. Everything’s fit perfectly and the springs are strong enough to hold the plate in place.


You have to adjust the Z-end stop to make sure the plate is not hitting the nozzle.
I did it manually to see how far up I can move the plate (make sure the glass plate is included).
Then I adjusted the Z-stop in little steps. I had nothing to add or modify.

  1. Connection to the main board
    I bought some connectors for the main board, to have a “professional” connection.
    The wires were soldered to the contact and pressed into the connectors.
    We needed the connection for the thermistor and the connection for the head bed relay, which will be my power expander.
    Actually I killed the first power expander from REPRAP accidentally.
    So I went to the local electronic shop and got a [color=#00BF00]12V relay[/color], which is used with 15V.
    No problems so far :slight_smile:

I soldered everything together and checked the electronic several times to make sure everything was connected correctly.

The steps:

  1. soldering the wires for the print bed (thermistor, power wires)
  2. soldering the contacts for the relay (power expander) to the 4 wire connector for the main board
  3. soldering the contacts for the thermistor to the 2 wire connector for the main board
  4. reconnect the PSU as needed
    5 straighten the wires for a nice looking


thanks for the informations,
what are the results with ABS ?


Hi Marc,
actually not.
I have no need for ABS.

At the moment I print the top cover for the printer.
That takes ages.



thanks for the informations,
what are the results with ABS ?


Does a MOSFET also work with this setup. I’m planning to do the same, but I’m looking for the best way to do it.

Yes. Have a look on my website to get a wiring diagram :

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