I've blown my controller. When I opened the controller up I found a capacitor rattling around ... unused, not soldered in, must have been solder shop quitting time and the Mrs had cooked a good meal. I have a 3 axis router with Lin Engineering 5718L 03D steppers and US Digital E2 optical kit encoders, limit switches and run it via a parallel port on Mach3. All these are in good condition. I'm looking for a suitable DIY controller kit with the entire kit and caboodle to run the mill efficiently. Do any of you know of a suitable kit and supplier? I am retired, do not have very deep pockets but still would like something of quality. A beer pocket and champagne taste so to speak. Look forward to your suggestions.

you write your Controller is blown, and also that everything is connected/running via a parallel port on Mach3.
so witch cntroller is blown?

some Pictures would be helpfull to get to the entire Problem.

I hope this jpg arrives, TPS. My computer, running Windows XP, is dedicated to Mach3 and is attached to the CNC via circuitry as per attached jpg. Each of the x,y and z axis stepper motors has 5 wires, blue, green, red, black, white and brown; each motor plugged via a 5 wire plug into a 'Motor' connector into the circuit board. Each US digital E2 optical kit encoder has 5 wires, red, green, bare, white and black, plugged into a 5 wire 'Encoder' connector. The limit switches are plugged in via a connector with red and blue wires. The circuit board is connected to a power supply via two white plugs, one with two green wires and the other with a black and green wire. The circuit board is connected to the computer via a 25 pin Parallel port cable to the computer's printer port.
The TIP120 transistor connecting the X axis motor's black wire to the PIC16F84A-201/P microchip has failed twice, while the transistor connecting the X axis motor's red wire to the microchip was not installed but loose in the circuit box. A friend soldered it onto the board. I did not know that one transistor was not installed till after the first failure. The burnt out transistor was replaced with a new one and the other was soldered in, and the machine ran well for a day when the new black wire transistor burnt again. All motors run well on the Y and Z channels, but the X channel is ratz. I think new circuitry would be required but I do not really know what to do next. Your advice would be greatly appreciated.

My attempts to send attachments result in errors, TPS, is there another way to do it?

witch error is showing up, sometimes it helps to rename the file to be unique.

Try again

My apologies, the transistors are attached to the DM7400N semi conductors, not the PIC microchips.

if the power Transistor for the x-Motor has blown twice i would start with the Motor itselv.
maybe your friend can measure the resistance of the Motor.

if you have two Motors of the same type you can compare.

Will do. I've also requested the tech specs from Lin Engineering as I do not know what each of the 5 wires are for. Let you know when it's done. Thanks

The circuitry.com file shows a circuit for unipolar stepper motors. 5 wire connection is a common configuration for unipolar motor. Unipolar motors are slower and less powerful than bipolar.
https://www.oyostepper.com/article-1076-Some-differences-between-bipolar-and-unipolar-stepper-motor.html

If you need to replace more TIP120s use TIP122. It has a voltage rating of 100V instead of 60V for the TIP120. This will help if your failures are caused by voltage spikes.

TPS's suggestion of swapping motors will help troubleshoot the problem.
One of the motor wires  will read the same resistance to all the other wires. Color codes vary but that common winding center tap is probably the white and brown wire.