CTX MKII Assembly Guide
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Table of contents
- Required Tools
- Optional Tools
- Component Sorting Sheet
- Standoffs and Header (Bag 1)
- Insert Standoffs
- Populate 8-Pin Header
- DOA Sockets (Bag 1 Cont.)
- Tape DOA Sockets
- Solder DOA Sockets
- Resistors (Bag 2)
- Bend Resistors
- Sort Resistors
- Place Resistors
- Solder Resistors
- Trim Resistors
- Capacitors (Bag 3)
- Populate Small Capacitors
- Quick Question
- Populate Large Capacitors
- Transformer and DOA
- Place Transformer
- Insert DOA
- Final Checks
- Finished!
- Help Us Improve
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 you run into problems, 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.
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.
Quick Question top
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:
Once assembled, insert the DOA into the socket.
Final Checks top
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Capacitor orientation: Is the stripe on the cap on the opposite side from the "+" marking on the PCB?
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Transistor orientation: Does the shape of the transistor match the outline on the PCB?
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Resistors: Are all the resistors in the correct positions?
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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.
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Trimming: Are all of the excess leads trimmed down as close to the joint as possible?
Before you wrap up, check the following things:
Finished! top
All good? Congrats on finishing your build! Have a question or problem? Drop us a line.
