Instructions for Version 3.0

These are the instructions for v3.0, if you have an older mintyboost you may want to check out the specific instructions for earlier versions.

Solder It!

The first step is to solder the kit together. If you've never soldered before, check the Preparation page for tutorials and more.
First! Check the Bill of Materials to verify you have all the parts necessary to make the kit.

Most importantly, check which version of the kit you have. Look at the packaging, and the PCB - find that v3 thats on the back near the top!
Place the PCB in a vise, and turn on the soldering iron. Make sure you have all the tools you'll need to assemble the kit.

If you don't know how to solder, we suggest checking out the videos in the link above. They're quite good! Keep them in a window so you can watch and review as you work through the kit
The first part we will place is the resistor R5 - this is a small oval tan thing with two wires (leads) and color stripes. The stripes are orange orange red which indicates a 3.3K resistor. This resistor is used to improve the high current capability of the boost converter chip and is a new addition to the mintyboost. The resistor goes right in the middle, over the silkscreen text that says R5.

Resistors are non-polar which means they don't have a direction: you don't have to worry about putting it in 'backwards' because they work the same either way.
Bend the resistor into a staple and slip it onto the top of the Printed Circuit Board. Bend the little leads out so that you can flip over the PCB and the resistor will stay in place.

Now you'll solder! Place the flat of the soldering iron tip against the silver ring (pad) and one of the wires of the resistor (lead) at the same time for 2 seconds. This will heat them both up to 600-700 degrees. Then poke the end of the solder so that it flows into the hole and forms a solder joint.

Solder joints should be smooth and shiny and fill the entire pad, wicking up to the lead. You shouldn't be able to wiggle the wire and have it move in the hole.

Now we will get rid of all that excess wire. Use your diagonal nippers to clip the wire just above the end of the solder joint. There should be almost no 'wire' sticking out.
Next up we will solder in the 75K 1% resistors R2 and R4.

These resistors are blue and have the following stripe colors: Violet Green Black Red Brown. They're very small and easy to confuse with the other blue resistors, but the other resistors have white and yellow stripes so perhaps look and make sure your resistors don't have any light stripes on them?

You might also have brown 7502F DALE resistors that are a little larger, in this case you can double the resistor over like this and solder it in the same spot. They wont sit flat but thats alright!

These resistors are used by Apple iPhones and such to determine what kind of charger is connected.
Solder the resistors as you did the 3.3K one, one point at a time, checking your work.
Clip the long ends.
We will now finish up with the resistors. grab the last two left, these are 49.9K 1% resistors and have Yellow White White Red Brown stripes. They go into the slots R1 and R3.

These resistors are used by Apple iPhones and such to determine what kind of charger is connected.

Solder them in.
Clip the leads so it's nice and tidy.
The next type of part we'll place is the ceramic capacitor. These are parts C1 and C2. Ceramic capacitors have a nice property that they are symmetric/non-polarized. That means they can go in 'either way'. Place the capacitor so that the 2 legs (leads) slide thru the two metal holes in the PCB (pads). The capacitor will sit flat against the PCB.

C1 helps stabilize the output voltage, and filters out high frequency noise so that the 5V output is nice and smooth.

Now it's time for the next capacitor, C2. This capacitor is used to stabilize the internal reference of the boost converter chip. This keeps the chip stable so that it will generate a voltage as precise as possible.

(We forgot to take a photo of placing them so we stole the next photo which also shows a black and white diode, don't place that yet...just the two yellow blobbies)
Solder and clip these parts!
Next is the schottky diode D1. This diode is part of the boost converter. Essentially it is used to make sure energy is transfered in only one direction-from the batteries to the USB port. Diodes have a special property that current can only pass thru them in one direction. That means that it is important to make sure that they are not inserted in backwards. Examine the diode and find the end with a white stripe. This stripe should match up with the silkscreen image, which also has a stripe on one end. In this image, it is towards the top.
Solder and clip the diode.
Lookin' good! Make sure there are no shorted wires or 'dirty' solder joints.

Next is the IC socket. This protects the chip and allows you to replace it if there are any problems. The socket goes over the 3.3K resistor but the resistor should not interfere as long as it was soldered in properly.

Make sure you solder the socket in so that the notch in the edge of the socket matches up with the notch in the silkscreen image of the socket. In this image it's near the bottom. If you mess this up, dont try to desolder the socket, instead just keep going and remember that it is upside down later when it's time to install the chip.

The socket has short legs so it can be annoying to keep in the right position. Hold it in place with one finger and 'tack solder' a corner.

Once that is done, solder in the remaining 7 pins. There is no need to clip.

Next is the power inductor L1. This component is used by the DC/DC converter chip to store and convert power from low voltages to high. Inductors are just a coil of wire so they have no polarity and can be placed either way.

The inductor may not sit perfectly flat, since the socket is in the way a bit. That's ok, just lean it over a little.

Solder in both wires and clip them short.

Next are the two electrolytic capacitors. These help smooth both the input and output voltages, to keep them stable during the up-conversion. They are used for low frequency noise, and are often paired with a ceramic capacitor.

Electrolytic capacitors are polarized and must be placed correctly or the circuit will not work. The longer lead is the positive (+) one and must go into the pad marked with a + as shown.

Solder in the two capacitors then clip the wires.

Next, solder in the 2xAA battery holder. The red wire goes to the hole marked + and the black wire goes to the hole marked -.

Make sure you have them in right or you can damage the circuit!

Solder in the wires, if they're a little long you can clip them.
Finally, carefully insert the boost converter chip. Make sure the notch in the chip matches the notch in the socket. If the socket was inserted backwards, make sure the notch faces the flat edge of the PCB as shown. Make sure the chip is seated all the way in and that the pins aren't bent.
Time to test! Clean up the desk so there are no little wire pieces that can short the kit (it's also just nice to have a clean desk).

We like to put down a piece of paper to ensure there's no chance of damage. Then insert two fresh AA batteries - alkaline or rechargeable is OK.

Wait a few seconds and feel the battery and chip. Are they getting hot? If so, remove the batteries and look over your work. The kit should not even get warm!
Use your multimter (hey you know how to use a multimeter right? If not, please read our voltage tutorial here) to measure the voltage in the two outer pins of the USB connector.

You should get a bit higher than 4.8V but lower than 5.2V.

If you get higher than 5.2V or lower than 4.8V, first check that your multimeter has a fresh battery. Really! this is a really common problem!

If you get lower than 3V, remove the batteries and check your work.
Next check between the rightmost pin and the second and third pin. They should both be at just about 2.0V

Once you are happy with these tests, remove the batteries and finish assembling the kit!
Next is the USB type A connector. This is the connector that is on a computer, and nearly all USB charging cables will plug into it. The Connector should snap easily in place.

The two large side connectors are used for mechanical strength. They keep the connector attached solidly to the PCB so make sure to use lots of solder or it will break off from use.

The four middle pins carry the power and data for USB. Solder in all four.

Now is a good time to test your kit - before you put it in the case. Check that it charges your favorite gadget and perhaps wait a few minutes to make sure that the battery meter inches up
If you are having trouble getting the device to recognize the Mintyboost as a charger, it could be because it only wants 'USB spec' chargers. This is easy to do with the Mintyboost and always worth a shot as it will get most stuff up and running.

Remove the batteries from your kit! Then using your soldering iron, heat up the two middle USB pins at the same time and blob on a bunch of solder to short them together.

Now try again!

Mintyboost® is a registered trademark of Adafruit Industries

This guide was first published on Jun 11, 2013. It was last updated on May 07, 2024.

This page (Solder it) was last updated on Mar 11, 2013.

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