MFOS WSG

My experience building the MFOS WSG - December 17, 2011

My level in electronics:  beginner

Upon receiving the WSG kit from MFOS, the first thing I did was sorting the resistors by value.  It's a bit hard to see the colors sometimes, so you might want to have a magnifying lens around

This is the circuit board.  I installed the components more or less from smaller to larger:

Resistors aren't polarized, so you can install them without worrying about which way to solder them.  Here's the PCB with the resistors installed:

Next I soldered the sockets for the ICs, and then placed the chips on top of them.  Be careful to set the orientation of the notches on both the sockets and the ICs to correspond to the schematic, or you risk ruining the chips!

Sometimes it's hard to keep the pcb from moving while soldering, so you might want to get a set of "helping hands" with the crocodile clips:

Next, I soldered the diodes in.  There are only two, BUT diodes are polarized, so make sure to follow the markings on the circuit board to set the cathode in the proper position:

Next I installed the transistors.  Again, there are only two but these are also polarized, so follow the "curvature" as in the diagram to install the base, collector and emitter:

Next I soldered the ceramic capacitors in.  There are three sets with different values, so sort them by size before installing them.  Ceramic capacitors are not polarized, so you can install these without worrying about their direction:

Here is the PCB so far, with the ceramic capacitors soldered in:

Next come the electrolytic capacitors:  these ARE polarized, so make sure to follow the markings and install the longer leg in the positive and the shorter in the negative:

Here are the electrolytic capacitors soldered on the board.  These were the last small components that needed to be soldered directly to the board.  The rest will require cables

Now I took a look at all the other components in the kit:  knobs, potentiometers (pots), switches etc.

It's very important to notice that the potentiometers are NOT all the same, even if they look like it:  they have different values, 100k, 500k and 1M, as you can see in this picture:

Per MFOS' suggestion, we need to perform some "surgery" to these potentiometers:  there is a small metal tab that gets in the way, so it needs to be taken out from each:

Like MFOS said, it's very easy to break off this tab from the pot; just grab it with a pair of pliers, and twist the wrist outwards until it breaks.  It's very easy to do.

The potentiometers mourning their fallen:

Next, I looked at the diagram (I have a laptop by my desk with the MFOS' website open) and set the potentiometers on top of their designated location by value:

and then I simply slid them up the desk, maintaining their designated location:

Now I needed to install them on the metal faceplate:  this is easy to do as there are the familiar hexagonal nuts and the washers.  In my set, each potentiometers had one hex nut and two washers, so I put one washer with the hex nut, and I left one washer on the potentiometer side:

Here are all potentiometers mounted in.  You can tighten these with the pliers, or even by hand:

This is a view of the potentiometers from the rear of the panel.  Note the orientation of the three terminals on each potentiometer, which follows MFOS' wiring diagram:

Next I mounted the switches.  Again, the switches have one hex nut and two washers. 

This time, for cosmetic reasons I decided to put both washers in the back of the unit, leaving only the hex nuts on the front - so this how I installed them:

Notice that the switches - too - seem to have that pesky little tab.  The switches have it on one of the washers, and by factory it's oriented outwards, like this.  This would get in the way when mounting them to the panel, so the easy solution is simply to invert the direction of the washer, placing the tab towards the inside.  This is from factory...

...and this is reversed.  See the tab?  Now is no longer a problem as it won't get in the way when placing the switch on the panel.

This is the first switch installed on the panel:

All the switches went in:

A view of the switches from the back:

and finally the audio jack goes in:

the audio jack from the back...

Now we need to start soldering cables in:  my kit came with 25 feet of 22-gauge stranded orange hookup wire:

You preferably need a wire stripper to strip the ends for all the cables needed:

The first wire goes in.  I didn't know how long to cut it, so took it large and measured 16".  I would later find that this was way too much and I ran out of hookeup wire.  Luckily, I had some other red, green and black spools of 22-gauge wire around

Since I'm new to electronics, I took it slow and checked and double-checked the wiring schematic.  I kept the laptop near me with MFOS' website open, to avoid mistakes:

By following the diagram, more wires go in and get soldered to the potentiometers and switches.  The first ones don't look so good, but as I went I think I improved my soldering technique.  Also note that there is a RESISTOR in here!  The only one that didn't make it on the PCB, the 470k one.

Spaghetti time.  As I mentioned, I ran out of the orange wire so I started using some other red, green, and black wire that I had:

In one instance, you need to solder two wires in one of the small holes on the PCB... so I joined two wires together and connected them to one: a bit messy, but it worked:

In another instance, you need to solder FIVE wires into one pot terminal... They were going all over the place so I used a crocodile clip to keep all five in place for soldering:

So keep soldering all the wires to the corresponding pots, switches and PCB points, and voila', at the end, you should have your WSG working.  I tested mine with a small Danelectro amplifier:

Now I wanted to make a wooden case to enhance the "vintage" look of this machine:  I went to Home Depot and bought some "nice" wood in 1/2" x 6" format (for the frame) and some "not so nice" wood for the back of the unit:

"Nice" wood for the front and frame:

"Not so nice" wood for the back:

I also bought some wood screws:

I measured the WSG and marked the wood accordingly - two sets of 7" and two sets of 8.5";   also I cut some 1/2" scraps to mount the front panel to:

I sanded the pieces of wood and took some wood glue:

I started making a frame simply by gluing.  Originally I wanted to screw the panels together, but this glue was strong enough so I just used that.

The case is all glued up...

Now I took those 1/2" scraps of wood.  I'll use them to mount the front panel on:

I glued the 1/2" scraps up and down, leaving a couple of millimeters space to account for the thickness of the WGS' metal panel:

here's another view of the 1/2" scraps all glued up:

and voila'!  It fits like a glove...

Next I marked with a pencil the location of the four screw holes...

... then I used a fine drill bit to pre-drill the holes, so the wood wouldn't crack when I installed the screws:

Now for the back panel:  I made a panel using the "not so nice" wood, measured the location of the four holes on the PCB, and threaded screws to the back of it:

and then I connected the PCB to the back panel:

and then pre-drilled four more screws in the corners and closed the back panel:

The knobs go in and voila'!  The WSG box is complete... It's not perfect, I know... I'm not the best carpenter... but it works.

Here's the WSG playing with other synths: