CTX MKII Assembly Guide

Safety Precautions, Warranty, and Disclaimer Improper soldering and handling of electricity can cause serious injury and damage to your property. Read and understand the instructions below before beginning your project. Follow the instructions, build carefully, and use the appropriate tools. Build at your own risk. DIY Recording Equipment, LLC is not responsible for any damage or injury resulting from the assembly or use of your kit. You are the manufacturer of your kit. It is your responsibility to turn this group of parts into a working piece of recording equipment. DIY Recording Equipment, LLC does not guarantee the success of your project and disclaims any Implied Warranty of Merchantability. Please visit the support forum for assembly support.
Damaged or Missing Parts All kits and parts are checked before being shipped to you. If something arrives damaged or if your kit is missing a part, please open a support ticket to inquire about a replacement. Missing parts will be replaced at our expense. Damaged parts should be returned for verification. If the part shows signs of use beyond what was necessary to determine that it was damaged, DIY Recording Equipment, LLC reserves the right not to replace the part.
Welcome to the CTX Colour assembly guide.

Thank you for purchasing a CTX Colour!

If this is your first DIY project ever, we recommend reading our Getting Started Guide.

This guide is for the CTX mkII, if you purchased the earlier version see the CTX mkI assembly guide.

Required Tools top

Soldering Iron
We recommend an adjustable-temperature station, such as the Weller WLC100.

Solder
You can use 60/40 "leaded" solder or lead-free. We recommend 60/40 because it flows better and is easier for beginners to use.

Wire Cutters
You'll need a pair of good "snips" for cutting of the excess leads after soldering.

Optional Tools top

Multi-meter
If a problem needs solving, a multimeter can come in handy. You can also use it to sort resistors.

Desoldering Pump
If you accidentally solder something in the wrong place, a desoldering pump can save the day.

Component Sorting Sheet top

To identify and keep track of every part in the kit, download and print the Component Sorting Sheet (PDF).

Standoffs and Header (Bag 1) top

Insert Standoffs top

Note that there are two different ends on the plastic standoffs. The locking end has tabs with a right angle to prevent them from being removed after installation, while the non-locking end has smooth tabs. Insert the locking ends of the standoffs from the bottom of the PCB.

Populate 8-Pin Header top

Insert the 8-pin header into the holes marked “CON1.” Make sure to place the short, silver pins through the bottom of the PCB so that the PCB rests on the black plastic posts. Solder the header from the top of the PCB and do not trim the leads afterward.

DOA Sockets (Bag 1 Cont.) top

Tape DOA Sockets top

Place the six DOA sockets in the PCB from the top. Then hold them in place with a piece of low-tack tape.

Solder DOA Sockets top

Solder the sockets from the bottom of the PCB.

Resistors (Bag 2) top

Bend Resistors top

Bend the resistor leads 90 degrees at the body so they can be inserted into the PCB.

Sort Resistors top

Resistor sorting made easy! Enter a value to find the color bands, or enter your color bands to find the resistor’s value. Type in the value of the resistor you need and this tool will show you the corresponding color code.

Place Resistors top

Place the resistors into their respective positions on the PCB. As you place each resistor, bend its leads against the bottom of the PCB so that it stays in place during soldering.

Solder Resistors top

Solder the resistors to the PCB. Observe good soldering technique: heat the pad and lead for 2-3 seconds, apply a small bit of solder, and continue to heat the pad for another 2-3 seconds. The finished joints should be shiny and should have just enough solder to cover the pad entirely.

Trim Resistors top

Use clippers to trim away the excess leads. Clip as closely as possible to the joint without clipping the joint itself.

Capacitors (Bag 3) top

Populate Small Capacitors top

Place the smaller capacitors in their respective places. These capacitors are not polarized and therefore can be placed in either direction. Solder then trim the leads.

Populate Large Capacitors top

These capacitors are polarized, so they must be placed in a certain direction. The positive lead is slightly longer, while the negative lead is marked with a stripe on the body of the capacitor. Place the capacitors with the positive lead in the pad next to the "+" marking on the PCB. Double check their orientation, then solder and trim.

Transformer and DOA top

Place Transformer top

Look closely at the transformer and find the four pins with small magnet wires attached to them. Insert the transformer into the PCB so that this row of pins faces the other components. The first of these wired pins will be inserted into the square pad on the PCB. If in doubt about the correct orientation, see the picture for the next step for reference. Flip the PCB over and solder in a 'zig-zag' fashion, alternating from one side to the other in order to prevent the transformer pins from overheating.

Insert DOA top

Follow the instructions in the RED-25 Assembly Guide:

RED-25 Assembly Guide

Once assembled, insert the DOA into the socket.

Final Checks top

    Before you wrap up, check the following things:

  • Capacitor orientation: Is the stripe on the cap on the opposite side from the "+" marking on the PCB?
  • Transistor orientation: Does the shape of the transistor match the outline on the PCB?
  • Resistors: Do all of the resistor positions correspond the chart and/or sorting sheet?
  • Soldering: Is every solder joint shiny and clean? If one is cloudy or misshapen, try reheating it for 8 seconds and adding a tiny bit more solder.
  • Trimming: Are all of the excess leads trimmed down as close to the joint as possible?

Finished! top

All good? Congrats on finishing your build! Have a question or problem? Drop us a line.

Help Us Improve top


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