Component Testing and Box Wiring (Part 1)

Not long after I had the holes drilled in the enclosure for everything, I bolted everything down excitedly, wired up the power supply, plugged it in and... nothing. The LED would not light, and checks with a multimeter indicated that there was no DC power coming from the output terminals. After dissassembly of everything and using a different power cord with similar results, I opened up the power supply (brand was AGT, for 'Advanced German Technology', looks like a Meanwell clone). I didn't see anything obvious (busted capactitors, burned resistors, etc), so bolted it back together with no success. I will say that these switched power supplies are not simple for the non-electronics type, and I suspect troubleshooting would be a pain.

This was a little over a year from when I originally bought it, and sure enough, long past a return period (though it probably would have been more trouble than it was worse). I sucked it up and bought a new Mean Well branded supply off Ebay, and when it arrived, went straight to checking it with an old cord I had cut up for this purpose.

LED Lit! Success! A Working Power Supply!

My original plan was to reuse some of the D-Sub connectors and wiring that came with the machine, but I decided it was going to be a pain to get these rewired and I wanted to use shielded wiring for the motors to limit interference into the limit switch cables. I really liked the GX16 style connector (4-pin) that is available on many of the hobbyist CNC suppliers, but they often ran $4 to $6 per connector... to pricy for me. I found I could get 10 for a little over $10 on Ebay, so went ahead and order some up.

I decided to use five connectors on the control box, and five connectors on the machine. For each side they would be:

• X Stepper Motor (using bipolar wiring, so only four wires needed)
• Y Stepper Motor
• Z Stepper Motor
• Emergency Stop (this uses two wires, leaving two left over if I ever wanted to add spindle speed control)
• Limit Switches (common power, one line for each axis)

The only fuses I was reusing in the control box were the main fuse and the spindle fuse, so the remaining fuse holes were good spots for additional connectors. To go along with these three locations I added two more nearby. Unfortunately, the fuse holder cutouts were too small, so I had to enlarge them (the GX16 connectors require a through hole for an M16 thread, or a hair bigger than 5/8". I removed everything from the control box to avoid chips in the electronics and drilled them out with a step bit, which work very well in thin metal like this. Since this is not a tool I use often, I picked up the bit at Harbor Freight for cheap.

Step Bit Used To Drill Connector Holes

Connector Holes Drilled

 With that, the box was cleaned back up to get rid of any chips or shavings that wouldn't agree with the electronics, and reassembly began.

First up, putting the wiring back in. I wired from the incoming outlet to the existing switch, then to the main fuse (I will try to find a good way to document the wiring if someone requests it). From here, power was split between the 36V power supply, the 5V power supply, the case fan, which runs on 120VAC, and the spindle fuse. The spindle power runs through the existing solid state relay, then over into the spindle outlet to go to the machine. Wire colors for the AC portions follow US wiring colors, with yellow or green as ground, white as neutral, and black as hot. Don't forget to ground everything.

The open fork connectors below go to the main power supply. The unconnected spade terminals are for the 5VDC supply, and the ring terminals go to the ground point, which I attached right near where the 5VDC supply goes.

AC Power Distribution Wiring In Place

Rechecking the Power Supply Again

Stepper Drives In Place

Next update I will cover the rest of the wiring.

Enclosure and Power Supply For Spectralight Mill

With my new electronics in hand, I wanted to reuse the old enclosure for a few reasons. First, it was setup with proper plugs for the spindle, along with fuses and a fan in there already. It has graphics for 'spectraLIGHT' on the front. And lastly, turns out enclosures aren't particularly cheap, so best to reuse and save the cash.

I took out the old control board and the power supply, but kept the fuse holders and the solid state relay for the spindle. I then rough mapped out where I wanted the components: main power supply in the front corner, stepper drivers across the center, and the C10 breakout board at the back, positioned such that the port would attach right where the 'MACHINE' decal was, which got it close enough to center to have good wiring access.

Rough Layout of Enclosure Box

To get the DB25 (printer/parallel) port on the C10 board out the back, I had to increase the size of the existing cutout. A little Google searching led to these dimensions for a DB25 port from cabledepot.com:

DB25 Cutout Dimensions

I rigged this up on my mill and cut in the new port. This could easily be expanded with a Dremel tool or similar for those without a mill that has enough Z travel to fit the box.

Milling Enlarged DB25 Opening

After that was some CAD work to punch in new holes for the drives, power supply, and breakout board. I've attached the hole pattern in an image below in case someone wants to use this as a starting point. I stress this was based off rough measurements, and some adjustment was required, especially with the breakout board (had to slot the holes slightly to get it to fit, so please verify on your own. This fits the KL-4030 stepper drives pretty well (a little tight), such that the flats of the nut hit the sides so you do not need to get a wrench in there. All these holes were punched in on the mill as well.

Enclosure Hole Pattern

Link to the higher resolution .pdf: PDF of Bolt Pattern

The documentation on the C10 board from cnc4pc (see here) states that the board should always be powered up if the computer is, due to risk of interference causing unintended movement. Instead of having a separate power supply to worry about or running another cable from the PC, I wanted to run a small power supply off of the same power switch as the main, such that they both turned on at the same time. The C10 requires 5 VDC at 400 mA. I've had several Android phones over the years, so pulled out an old charger to see it fit the bill. Sure enough, most that I found give 5VDC at over 400 mA, so I busted one open to see if I could adopt it here.

Here's what I'm talking about. This is a different charger but I've lose the image of what the charger looked like originally. I suspect almost any cell phone charger will do, as long as it has enough output capacity. All the phones I've got have a USB output.

Phone Charger Similar To That Used For 5VDC Supply

To mount it, I grabbed a couple of Nylon spacers from Home Depot and tapped the ends for a 10-32 screw. I roughed up the other ends with some coarse sandpaper and then used JB Weld epoxy to attach them to the bottom of the board (I did a little research, didn't seem to be a standout solution for bonding Nylon. The JB Weld is working for me, but is probably pretty fragile, so I handled it with care. JB Weld is non conductive.). Not a lot of room there due to the components, so it didn't come out looking very fancy.

Spacers For 5V Power Supply

 

5VDC Power Supply Board With Spacers In Its Proposed Location

 I soldered on some wire to the two line power contacts with some quick contacts at the ends. On the charger I used, along with my others, the plug does not appear polarized, so I don't think you need to worry too much about figuring out which contact is hot and which is neutral.

5VDC Power Supply With Wires and Supports Attached

In the next post I'll talk about why it's important to try you equipment when you receive it.

Updates Coming

It's been quite awhile since I posted on here (a year and a half roughly). I've done quite a few things in the garage since then, but have yet to post anything up (pretty obvious). I have, however, been trying to take photos along the way, so I can try to backfill on some of this stuff. So hopefully I'll get a regular set of posts going in the next few days. Things complete that I plan to have a few posts about:

• Finishing up my small Spectralight mill electronics
• Cleaning and low-dollar refresh of my Lagun mill
• New (bigger and badder) lathe
• A few product reviews

Cheers,
Joel