TM79 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
- Tape and Solder IC Socket
- Resistors (Bag 2)
- Bend Resistors
- Sort Resistors
- Place Resistors
- Solder Resistors
- Trim Resistors
- Capacitors and Transistors (Bag 3)
- Populate Small Capacitors
- Populate Large Capacitors
- Populate Transistors
- Transformers (Bag 4)
- Place Transformers
- IC (Bag 5)
- Place IC in Socket
- Final Checks
- Help Us Improve
Required Tools top
We recommend an adjustable-temperature station, such as the Weller WLC100.
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.
You'll need a pair of good "snips" for cutting of the excess leads after soldering.
Optional Tools top
If a problem needs solving, a multimeter can come in handy. You can also use it to sort resistors.
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.
Tape and Solder IC Socket top
Insert the IC socket so that the notches on the sockets align with the markings on the PCB. Secure in place with tape. Then flip the PCB over and solder in place. Remove the 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 and Transistors (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.
Populate Transistors top
There are two important things to note about transistors. First, the orientation: one side of the body is flat while the other is round. And second, the part number: carefully check the markings on the sorting sheet against those on the body before inserting them.
Identify the transistors, place them in the correct positions orientation, double check, and then solder and trim.
Transformers (Bag 4) top
Place Transformers top
Place the transformer in the X1 and X2 positions. Note that there's a small notch in the plastic near pin 1. Line this notch up with the corresponding one on the PCB, then solder the transformer to the PCB. To prevent damaging the transformer, leave 20 seconds between solder joints. This allows the coil wires time to cool down between joints.
IC (Bag 5) top
Place IC in Socket top
The leads of the IC must be slightly bent to fit perfectly into the sockets. Press one row of leads against a flat surface until they form a 90-degree angle with the body of the IC. Then do this for the other row.
IC polarity is indicated by a dot or notch on one side of the body. Align this side with the notch in the socket. Place the IC in this direction, and press it completely into the socket.
Final Checks top
Before you wrap up, check the following things: