T3P3 Kossel Mini Kit Release 3

Assembly Instructions

Chapter 12 - Electronics, power plate and electronics cooling fan

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1201 Electronics - Parts needed

Printed parts:

Duet faceplate

Duet rear mounts x 2 (see Note below)


M4 x 8 button head socket screws x 8

M4 T-nuts x 8

No 2 x ¼ posi pan self-tapping screws x 2

M2.5 flat washers x 2

Note: The main picture shows the original design of Duet rear mounts. These have now been strengthened  as shown on the right.



Make sure you take precautions not to build up electrostatic charge while handling the electronics - refer to the Introduction for more details.

Electronic Controller

Duet V0.8.5


1202 Fit Electronics

First check that the front edge of the Duet fits cleanly through the printed faceplate. Rest the faceplate face down (smooth side up) on a flat surface and insert the edge of the board.

Check that about 3mm of the board can be pushed through the faceplate, then remove the Duet.

Mount the 2 Duet rear brackets on the inside of the lower X-Y and X-Z extrusions using 4 M4 x 8 button head socket screws and 4 M4 T-nuts. Do not tighten fully.

Fit the Duet faceplate to the outside of the Y-Z extrusions using 4 M4 x 8 button head socket screws and 4 M4 T-nuts. Do not tighten fully

Slide the Duet front edge into the faceplate until it emerges from the front. It is a tight fit between the motors and you may need to slide the faceplate to one side or the other to obtain an equal clearance between the board’s long edges and the motors. Tighten the face plate mounting screws.

Push the Duet through the faceplate until it is projecting about 3mm, as before.

Align the Duet rear mounting bracket posts with the PCB mounting holes, then tighten the M4 button head screws holding the brackets to the extrusions. Adjust as necessary to keep the mounting holes aligned.

Finally fix the Duet to the mounting posts with the 2 No2 x ¼ posi pan selftapping screws.

1203 Fan - Parts needed

40mm fan

M3 x 16 socket capscrews x 2

M3 penny washers x 2

M3 T-nuts x 2

M3 x 12 male/female nylon standoffs

1204 Fit fan

Fit the fan to the nylon standoffs with the cable emerging between them and the fan label on the opposite side to the standoff (left side in this picture). Do not tighten fully - the nylon standoffs will tend to lock into the hex nut holes in the fan casing, but you need to be able to turn them when fitting the fan to the extrusion.

Fit the penny washers and M3 T-nuts to the M3 male threads on the standoffs.

The assembly should look like this. Make sure the fan label is visible on the downstream side of the assembly.

If you have the original Duet rear brackets then you can fit the fan to the inside top X-Z extrusion, over the Duet rear bracket, so it faces the rear corner of the Duet on the 50-way expansion header side. Tighten the plastic standoffs first and then the M3 x 16 capscrews.

If you have the revised Duet rear brackets with stiffening web then fit the fan to the top X-Y extrusion on the opposite side of the Duet instead.


1205 Power Plate - parts needed

Printed power plate

Power input socket with cables

Power switch

M4 x 8 button head socket screws x 4

M4 T-nuts x 4

1206 Fit power plate

The plate is fitted to the X-Z side of the frame base.

First fit the Molex 10-way power socket to the printed plate.

Note: The plate has been printed with very little clearance to ensure that the panel-mount plug stays snapped into place once fitted.  It may require some force to push the plug fully in. If it won’t fit, carefully cut away a little plastic until it does.

Fit the on-off switch to the plate. It should also be a tight fit. Fit the bayonet connectors to the spade terminals on the switch. They are not polarised so can go either way.

Fit the power plate to the X-Z side of the base, towards the front. Connect the power leads to the Duet as shown.

1207 Test Power supply

Put the printer power switch in the OFF position.

Connect the Dell DA2 power supply unit to a mains outlet socket with the power lead provided, but do not switch on yet. Plug the Molex-type 12V DC lead into the left-hand 8 ways of the 10-way socket you have just fitted to the printer.  (We had to use a 10-way socket because the Dell plug will not fit a standard 8-way one).

Leave the printer switch OFF and turn power ON at the mains. The LED on the PSU should glow amber or red

Turn the printer switch ON and the LED on the PSU should change to green.

Switch the printer power switch OFF, switch OFF and unplug the power lead at the mains outlet, disconnect the power supply from the printer and  set it aside for later.

Now go on to the next Chapter.


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