Electronics Layout

The next task is to lay everything out in the top enclosure. I have already played about in sketchup and given it lots of thought, so I have a good idea of where to put things. I want to keep the mains as far away from everything else as possible, so this is what I came up with...


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The 24V PSU, PC PSU and spindle PSU/controller are all located in the bottom left. The mains input will be top left, and the mains switches will be located on the front panel in the bottom left corner of the above picture. The plan is to have an IEC C14 chassis socket for the mains input. This will run down to the main on/off switch and then feed the PSUs and run back to a IEC C13 chassis socket, which I will use to power the monitor. I will also have a separate switch to turn the spindle PSU on and off as an added safety feature. This means a single rocker switch will switch the whole unit on and off, including the PC and monitor. With the locations decided it's time to start fixing things in place.

I managed to find a PDF template for the motherboard, which is an Intel DG41AN in case you are interested, and then simply printed it off and taped it in place. I drilled some 3.175mm holes, which were perfect for screwing the standoffs in place. I used a 2.5" to 3.5" mounting plate to mount the 2.5" SSD drive using a couple of mb standoffs. I made more paper templates for the PSUs and simply drilled the holes and screwed them in place. Here's the finished layout...

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The only thing missing is the addon board which you can see top middle in the first picture, I haven't decided where to put it yet, but it will probably go just below the motherboard or just to the left of the SSD.

Next up I need to work out where to run the wiring, the mains (cyan) and 24V (red) lines in the picture below are pretty much settled. I am not sure which route to take the spindle (yellow) output though, is it better with the 24v lines or running down the left with the mains? I could keep all the mains wires on the bottom and the spindle wires to the top, this would give about 100mm of clearance between them. I think I am going to use the 2nd option, unless anyone has a better suggestion.

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The last job for today is to make some new connectors to run from the stepper motor driver boards, to the chassis connectors. As the stepper motor drivers are mounted right at the back, I only need about 100mm long wires to connect them. I first had to identify the connectors used so I could order some more. A quick google, proved them to be Molex 2139, which were not too hard to get hold of. While making up the new connectors I couldn't help but notice that all 3 stepper motor connectors are wired differently, with relation to the pinouts on the driver boards an the pin numbers on the 4 pin chassis connectors. I will redo these later, to make more sense, but need to wait until I rewire the connections back to the stepper motors. I also love the way the Chinese just wire things in random colours to match the random order. You need to pay very careful attention to what goes where before you take it all apart, taking pictures and making notes where necessary.