How to Assemble a Cthulhu PCB.




Introduction: How to Assemble a Cthulhu PCB.

The Cthulhu PCB is a microcontroller based board made to go inside an Arcade stick so the stick can be used on a PC or Playstation 3 via USB. This board is available as an already assembled piece, or in a kit form for cheaper.

This Instructable will guide you through the assembly of a Cthulhu kit.

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Step 1: Identify Parts

Before you get started, verify you have all of the parts needed to assemble.

The first picture below shows all of the parts included in the bare Cthulhu kit:
-1x 20 MHz resonator (Orange, three pins, '20MHZ' written on it)
-1x .1uF capacitor (Blue or yellow, two pins, '104' might be written on it)
-1x .47uF aluminum capacitor (Black cylinder, two pins, '.47uF' written on it)
-1x 10uF aluminum capacitor (Black cylinder, two pins, '10uF' written on it)
-2x 10 pin 10Kohm resistor network. (Black or yellow, ten pins, text written on it)
-1x 28 pin IC socket
-1x printed circuit board
-1x 28 pin PIC microcontroller (not shown)

The second picture shows two optional items as well:
-1x USB 'B' jack
-2x 10 pin screw terminals with 5mm pitch.

Both of these items are optional, but the USB jack is highly recommended.

If you have ordered an 'MC' (multi-console) Cthulhu, you will also receive:
-2x small glass diodes
-2x larger black diodes
Both are pictured in the third picture below.

Step 2: Select Your Power

On the lower right corner of the board is a collection of spots for diodes, along with a jumper labeled 'USB Only'. All of the power to the board comes from this area.

If you are using an original Cthulhu, for Playstation 3 or PC USB only, then your kit should not have come with any diodes. In order to make sure your board gets power, you need to solder together the two points labelled 'USB Only', pictured in the first image. This is very easy to handle but still must be done. Heat up your soldering iron, and prepare to get messy. Melt an obscene gob of solder on the end of your iron, and use it to connect the two pads of the jumper labeled 'USB Only'. Keep going until they're connected. The second picture shows a completed jumper.

If you are assembled a multi-console 'MC' Cthulhu, your kit should have come with four diodes; two glass, and two larger black diodes. Before we install them, we need to make sure we put them in properly; if they are put in backwards, it won't cause any bad problems, it just won't work, so let's get it done right the first time.

Look are the first image, in particular at the white rectangles labeled 1 through 3. You'll notice there is a band on the image, on the end of the rectangle closest to the spot in between all of the diodes. Check both your glass and black diodes; there are similar bands present there; black on the glass diodes, and a white or grey on the black diodes. When you install the diodes, the bands MUST be on the same side of the diodes as shown on the silkscreening. The 'USB Only' jumpers cover where the rectangle should be for that spot; that's fine. The orientation is the same as the #3 diode beside it. The bands always go on the end closest to the middle of all four diodes.

Take your glass diodes, and lightly bend the legs down. Take the first glass diode, and insert the legs through the holes on either side of the 'USB Only' jumper. Pull the legs through so the diode is flat against the board, and bend the legs out from the bottom to hold it in place. Take a moment to look at the diode and make sure the band is on the same end as shown in the silkscreen for #3.
Take the second glass diode, and insert the legs into the holes on either side of the #3 silkscreen. Check that the band is on the proper end, same as the first diode. Bend the legs out to hold it in place. Flip the board over, solder all four legs, and clip off any extra wire from the legs.

Take the two black diodes, bend the legs, and insert them into diode spots #1 and #2, making sure the band is on the same side as shown in the silkscreen. I will warn you, the holes are barely bigger than the legs. On all of them I've done, I've had to poke the legs through a little and use a pair of pliers to pull the legs the rest of the way through so the diode lies flat against the board. Once they are flat, bend the legs out to hold them in place, flip over, solder and trim.

If you are converting a PS3 Only Cthulhu to a MC Cthulhu, use your soldering iron to melt the solder on the 'USB Only' jumper so it no longer shorts the two jumper pads. Once that is done, install the four diodes as described above.

NOTE: If you are converting a PS3 Only Cthulhu to a MC Cthulhu, and the Cthulhu board is the 1.4 revision (listed on the bottom of the board) that already has four black diodes installed, do NOT do any soldering or desoldering. Simply swap chips and your Cthulhu is upgraded. The instructions above assume you are using a Cthulhu board that does not have the diodes already.

Step 3: Solder Resistor Networks

The first parts to solder to the board are the resistor networks. The color of the network may vary from the picture below, but the important thing to note is that all of them have writing on one side, towards one end of the network. This helps to mark which pin is 'pin 1'. It is possible to put these in backwards, and that could be a bad thing, so make sure you understand which way these go in.

The end of the network with the writing on it is pin 1. The second picture below shows where they go on the board, and which end is pin 1. Make sure the writing is on the end marked with the 1, and poke the legs through the holes.

Turn the board upside down, and solder ONE of the legs of each resistor network. This is just to hold it in place. Turn the board back around and look at the network. It will probably be at a bit of an angle. Melt the solder around the first network, adjust the network so it is fairly straight (perpendicular to the PCB) and let the solder cool so the network is held in place. Repeat for the second network.

Once both networks are in straight, flip the board back over and solder the other nine pins of each network.

Step 4: Solder IC Socket

Intergrated circuit chips (IC's) can be damaged by excess heat, such as the heat of a soldering iron. In order to make sure our chip isn't damaged by the heat of soldering, we will be using an IC socket. The socket by itself gets soldered to the board, and later the chip will be inserted into the socket, keeping the heat far away from our sensitive chip.

The IC socket, the IC chip, and the image of the IC printed on the board itself all have a notch on one end. This easy identification lets you know which way the chip and socket should go into the board. Locate the notch on the IC socket and the printed circuit board. Insert the socket so the notches are on the same end. Flip the board over, and solder the 28 different legs of the socket.

Congratulation, you have already done more than 75% of the soldering. We have a couple of more parts to install, but only a few soldering points left.

Step 5: Electrolytic Capacitors

We have four parts left, so let's get half of them done in one go.

First is the two electrolytic capacitors. These are the two dark colored metal cans. One has '10uF' written on the side in small letters and is usually larger than the other. The other capacitor has '0.47uF' written on the side in small letters. Make sure you know for sure which of the two is the 10uF capacitor, and which is the 0.47uF (470nF) capacitor.

With these two capacitors, it is possible to put them in backwards, and you don't want to do that. Of the two legs, one is 'positive', the other is 'negative', and there are a couple of different ways to know which one is which.

First, there is a grey stripe on the side of the cannisters. The pin closest to this stripe is the negative one.
Second, one leg is longer than the other. The longer leg is the positive leg, and the shorter leg is negative. You'll notice on both capacitors that the shorter leg is closest to the grey stripe.

Now that you know which leg is which, let's put them in place. Grab the bigger capacitor marked 10uF. Locate the spot labelled 'C3' and '10uF' on the board. Inside the circle is a small plus sign '+'; that tells you which leg is positive. Put the longer, positive leg through the hole with the '+', and the negative through the other hole. Push the capacitor all of the way through. Bend the legs outward to hold it in place. We're going to put the other capacitor in before we solder the legs down.

Grab the capacitor marked 0.47uF. Locate the spot labelled 'C2' and '470nF' on the board. Again, one hole is marked with a '+', so put the longer positive leg through there, and the negative leg through the other hole. Pull the capacitor through all of the way and bend the legs to hold it in place.

Flip the board over. We're about to solder the legs in place, but let's take one last moment to verify we're putting the capacitors in properly. The pads the legs are sticking through should have one square pad, and one round or octagonal pad. The longer (positive) leg should be going through the square pad. If the longer leg of each capacitor is going through a square pad, you have it in properly. Solder the legs to the pads and trim them short with a wire cutter.

Step 6: Ceramic Capacitor and Resonator

Only two parts in the kit left to go, a total of 5 solder points, and we don't even have to worry about orientation. You're almost done.

The ceramic capacitor is very small, and has '104' written in letters you might not be able to see without a magnifying glass. The main thing here is that there are two legs. The other piece, the resonator, is bigger, has '20MHz' written on the side, and has three legs.

The two-legged ceramic capacitor goes into the board in the spot marked 'C1'. There is no orientation; you cannot put in it backwards, so run the legs through the holes, pull it all of the way down, and bend the legs outward to hold it in place.

The three-legged resonator goes into the spot marked 'Q1'. There is no orientation; you cannot put in it backwards, so run the legs through the holes. The legs are a little too short to bend, so just hold it in place with a finger, and flip the board over so it rests on the resonator with the three legs poking through the board.

Solder these five legs, and trim them short with a wire clipper.

Step 7: Optional: USB Jack

A USB jack doesn't come with the Cthulhu kit because a number of people want to use the Cthulhu along with an Xbox 360 pad to make a stick compatible with both Playstation 3 and Xbox360. This doesn't require a jack so no one is charged for one unless the need it.

Unless you are doing the above, the USB jack is HIGHLY recommended, and will result in a much higher quality of stick. This step covers installing the USB jack.

There is only one place where the USB jack can be installed, so you can handle this step with confidence. Place the jack onto the board, and flip the board over. There are four small holes for the USB lines, and two very large holes that physically secure the jack in place. Solder ONE of the four small points to hold the jack in place while you work. Make sure the jack is all of the way flush with the board, perfectly flat. If not, melt the solder on your one point, adjust until its flat, and then let the solder cool.

Once the USB jack is perfectly flat against the board, solder the other three small connections.

The larger holes may seem tricky at first, but it is a simply thing to solder to those large holes; use lots of solder. You'll be surprised by how much solder you have to add before those holes close up, but they eventually will. Heat up one leg with the soldering iron, and keep adding solder until the hole closes. Repeat for the other leg.

Step 8: Optional: Screw Terminals

The spots for connecting the buttons and stick to the Cthulhu board are well spaced and fairly large. Soldering wires to those points is actually very easy. However, some people would prefer that the wire-to-board connections weren't soldered and wouldn't require solder; for those people, a pair of screw terminals can be added.

The screw terminals should have 10 pins each, and are soldered to the labelled points on the sides of the board. You will want the entry points for the wires facing the outside of the board. Inset into the holes, flip the board over, and solder the ten points each.

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    12 Discussions


    11 years ago on Introduction

    Very nice Instructable! where might I find this kit for purchase?


    Reply 11 years ago on Introduction

    For now, I'm selling them directly. Details on ordering are available here:

    Feel free to look through the thread in case there are you questions you may have; you can also see pictures from at least one customer. In time, I hope to have the boards available through, but negotiations are still underway.

    Let me know if you have any questions.


    Reply 8 years ago on Introduction

    Can I still buy a DYI kit? The link above is dead.


    Reply 10 years ago on Introduction

    do you send to the uk or know of a supplier of these in the uk?? if so who?? if you do send, what is the price for a un-assembled kit with usb??


    8 years ago on Introduction

    I have a 360 stick now that I'd like to use on other consoles. I found out this has Gamecube support but does it also have Wii support? I wanna use it on the Wii U, and from what I hear that will support Wii but not Gamecube acccessories...


    10 years ago on Introduction

    would the 'MC' Cthulhu alow me to use a ps2 or ps3 controler on an xbox 360


    Reply 10 years ago on Introduction

    The Cthulhu PCB is a microcontroller based board made to go inside an Arcade stick so the stick can be used on a PC or Playstation 3 via USB.


    10 years ago on Introduction

    Hi, great project! Is the PIC code available online, or for purchase? Would love to test it out. Thanks

    This is sweet! Do you think you could get 2 of these and connect them together via a usb and then you could send 20 wires through a usb instead of 4?