[systemslave]

I have recently acquired both a D&M CNC lathe and mill. As I have gone looking for information on the electronics it has become apparent that there are not a lot of resources out there. Since I am doing the reverse engineering myself I will post what I know for others who follow. If someone knows where this information is already posted let me know. I don't need to re-invent the wheel.

My machines are a D&M3 machining center and a D&M4 lathe. Both use the same electronics. Each has a logic board, a stepper driver for each axis, a motor interface board, and a speed controller for the spindle.

[systemslave]

Attachment 196520Messing around on the inside of the electronics cabinet can hurt you or kill you. The spindle motor runs on 115 volts, so this is not like playing on the electronics of a transistor radio. Your boards may not be in the same places as mine. This is a picture from the lathe which only has two steppers.

[systemslave]

Attachment 196522The stepper cards are labeled "Z AXIS" or whatever axis they run. They are really simple. They have one stepper control chip and four transistors to run the four steps. There are three cables connected. The one with four big wires goes out to the stepper motor. The one with two wires provides power to the stepper motors which is switched by those transistors. The connector with four smaller wires tells the board what to do. It has power for the chip on two of the wires. The other two wires tell the stepper chip which direction to move and how fast. The speed is controlled by turning one of the wires high and low (oscillating).

If you are a technician you are highly aware that I am really simplifying this information. I figure that if you know where I am taking liberties you don't need to read this anyway. You can look at the chips and see what is happening just like I can. Therefore I am writing this for those who cannot look at the chips and see what is happening.

[systemslave]

Attachment 196526The motor board runs the spindle. It is a PUMA SM board in both of my machines. It is a very cool board that will keep your spindle turning at a relatively fixed rate compensating for the work you do. Of course it is limited by the power of your spindle motor. The take away here is that this is a board worth having all by itself and not one of the custom boards. Notice how much denser the layout of the PUMA board is? Google the PUMA SM for the docs.

[systemslave]

Attachment 196536The motor interface board tells the PUMA board how fast to spin the spindle. Eight wires encode the desired speed and two wires control the logic. I have diagrammed the board to make it easier to understand. There are 10 wires in the cable that attaches to this board. All of the wires are optically isolated from the rest of the board. The PUMA board is looking for an analog input. The chip sees the digital pattern from the cable and converts it to an analog output for the PUMA board. That output goes out the three wire cable to the screw connectors 1,3, and 4 on the PUMA board. Look up the specs on an AD558JN if you want to understand the magic.

If you want the short version, all chips run on magic smoke. As long as the magic smoke stays in the chip it will work. When the magic smoke comes out the chip is worthless.

[systemslave]

This brings us to a magic place. The only board we have not documented is the controller board. All of the advice I have seen so far has said the same thing about this board. Lose it. Replace it with a cheap break-out board. You can run all of those other boards with a cheap break-out board and free Linux CNC software. You will have to decide if that is right for you. I am making that decision right now.

Why lose it? It is designed to work with proprietary software that is not as powerful as modern software and only runs on very old machines. It does not have the capabilities of newer software so using limits your CNC toys. Also, if you are reading this you don't know how to use it without advice and I have not bothered to figure it out yet. I probably won't bother because I understand how it limits the entire machine. It was, after all, made to teach high school students about CNC concepts in the 90s.

Why keep it? A model-T with a modern engine is not a real model-T is it?

[Mattster1]

Thanks for sharing the information you have gathered so far. I have picked up a D&M Colne 5 lathe which runs on a commodore 64 and uses a special cassette in order to run it. I am in the process of trying to determine the best course to replace the control system with a newer computer (PC based) and CNC control system. Along with updated motors, controller cards, breakout board etc.

I am looking for suggestions as to what electronics I can or should salvage off the original lathe such as the spindle motor/control system which does not look like your photos, it is 110v DC which is marked on the motor.


This is my first attempt at doing this so I am a complete newbie at this and may have some dumb questions for anyone who responds to the thread but I will try to keep them to a minimum.

I will share my success or failures as the project progresses.

Thanks,

Mattster1

[rudyeb]

Attachment 196536The motor interface board tells the PUMA board how fast to spin the spindle. Eight wires encode the desired speed and two wires control the logic. I have diagrammed the board to make it easier to understand. There are 10 wires in the cable that attaches to this board. All of the wires are optically isolated from the rest of the board. The PUMA board is looking for an analog input. The chip sees the digital pattern from the cable and converts it to an analog output for the PUMA board. That output goes out the three wire cable to the screw connectors 1,3, and 4 on the PUMA board. Look up the specs on an AD558JN if you want to understand the magic.

If you want the short version, all chips run on magic smoke. As long as the magic smoke stays in the chip it will work. When the magic smoke comes out the chip is worthless.

I am working on updating a D&M 6 mill and was hoping you might direct me to whereI might see the attachments that you had posted to this site?

Would you know the voltage of the stepper motors?

Thank you,

Rudy