Assembly instructions for the MOTM version of the Blacet / Wiard Miniwave
If you have decided to build the Blacet / Wiard Miniwave and convert it to the MOTM format,
you have no doubt found that this procedure is more complicated than simply purchasing and
building a Synthesis Technology MOTM kit. And, you have found that Blacetís concept of
"MOTM versions" of his kits is simple omission of the parts you would not use. The additional
parts you need are not included. The instructions are not revised to reflect the changes involved
in conversion to the MOTM format. Instead of having everything you need delivered to your door
in one neat package, you must accumulate parts from a variety of sources. Here is what you
need to get started:
I will not attempt to list the part numbers here. Changes and a variety of vendors and suppliers make that
task unreasonable to include in the assembly instructions. Instead, I will refer you to "the" definitive MOTM
compatible parts reference assembled by Dave Bradley. Visit http://www.hotrodmotm.com/parts_list.htm
for everything you need to know about where to get these parts.
You will also need to refer to your original Blacet assembly instructions for the graphics including the
schematic and PCB drawings. I cannot include those in this document without infringing on Johnís
copyright (which, of course, I would not do).
Before you begin with the electrical construction, you have some mechanical issues to deal with. My PCB
mounting brackets are universal and are not specifically made for a certain PCB. Some modifications are
required to the four-pot long mounting bracket to work for this assembly. I have taken several photos of the
construction process for my Miniwave. You will find relative hypertext links to the photos throughout these
instructions in the HTML version. If you are reading the HTML version of this document on-line at
www.wiseguysynth.com, these links will take you directly to the photos. If you have saved this document to
your hard drive for reference, you will need to save each photo to the same directory as this document. The
photo links will then work for you off-line. You can take a quick tour of all photos here. MS Word and text
document users need to view photos separately.
Two modifications are needed to the four-pot long bracket. Both end pot holes must be extended to the
upper edge and side of the short side of the bend. This will knock out the interference between the bracket
and the location of the LEDs on one end and the switch on the opposite end. I originally thought only the
LED end would need trimming. But, when I went to mount my switch, I found the lock washer would not sit
flat without the bracket trimmed. So, some of the photos show only one side trimmed. Now, you know why,
and you know better. I have my PCB on the left side (looking from the back) like MOTM modules. However,
it will work either way. Putting it on the left as I did causes the PCB to be upside down from its original
configuration. However, since no pots are board mounted, it really makes little difference. [photo] [photo]
The second modification requires drilling two holes for mounting the PCB to the bracket. Unlike earlier
Blacet PCBs, the Miniwave does include mounting holes. However, they are slightly undersized for # 6-32
machine screws. Fortunately, two of these holes line up perfectly with the middle set of holes in the bracket.
Two additional holes must be drilled near the back of the bracket. I recommend a 5/32" hole in the bracket
if you plan to use # 6 hardware.
Since, I did want to use # 6 hardware, I decided to drill the holes in the Blacet Miniwave PCB slightly larger.
The correct size drill is 9/64 inch for a # 6-32 screw to go through the PCB. If you do not want to drill your
PCB, change to # 4-40 hardware. Reduce the size of your hole drilling in the bracket to 1/8 inch.
This might be a good spot to make sure all your mechanical parts go together well before you move to
soldering. Mount your PCB to your bracket using stand offs. Attach your bracket to your front panel using
two of the four pots. Do not forget to install backing nuts on your pots. This is CRITICAL. The concept of my
mounting brackets is that the bracket is held in place by sandwiching the bracket and front panel together
between the back nut and front nut on the pot shaft. You cannot tighten against the pot body. You will have
nothing but trouble if you try. You should always use backing nuts on your pots. Hopefully, everything fits
together well in your trial fitting and you are ready to heat up the soldering iron.
I will confess that I have been spoiled by the completeness of MOTM assembly instructions. The Blacet
instructions are not nearly as complete, leaving the assembler to jump back and forth between the
schematic and parts list to figure out what part goes where. As I write these instructions for the conversion
to the MOTM format, I am also adding to the Blacet document some more specific instructions that I
believe are easier to follow. I also changed the relative order of the component placement on the PCB.
First, a word about solder. I am assuming that you will follow the MOTM solder standard and use organic
solder (requiring a board wash) for much of the soldering, and then switch to a no-clean solder to
complete the construction. If you adopt another strategy, you are on your own concerning the need to
wash the PCB.
I like to install my components based on relative height. It seems to be easier for me. However, feel free
to jump around the instructions to suit yourself. I started with the individual resistors.
PART 1: Installing the individual resistors (network resistors later) and diodes
You will use organic washable solder for this part of the construction.
First, the 1% tolerance blue resistors:
Now, the 5% tolerance resistors:
That completes the installation of all the individual resistors. Next, you add the diodes. Please note that
3 different diode types are used in the Miniwave. Use care not to confuse them. And, be certain to note
polarity. The arrow on the PCB points toward the stripe on the diode.
PART 1 continued: Installing the non-electrolytic capacitors
This completes the installation of all capacitors except the larger electrolytic. Do not confuse the PS1 and
PS2 resettable fuse-like devices as capacitors. They resemble small ceramic capacitors but are
distinguished by preformed leads and are marked "R010BOVS." You will install those later.
OK. This is a good stopping point for our first board wash. Run the board under warm water (do not use
any soap or cleaners). Gently scrub both sides of the board to remove the organic flux. Any small brush will
do the job. I use an old toothbrush.
If you have not done so already, this would be a good time to inspect your solder joints. Check to be certain
you have not forgotten to solder one end of a component or that you have not accidentally bridged one
thing to another with excess solder. Personally, I check my joints right before I clip my leads. It seems
easier to me to find what I have just competed that way. Here is what your PCB should look like:
PART 2: Installing the remaining components on the PCB
Next you will install the resistor networks. Notice that each resistor network has a white dot on one end. Be
absolutely certain to align the resistor networks on the PCB so the white dot is at the end indicated by the
white dot on the PCB. Before you insert your resistors, check that the pins are not bent. Bend them as
needed to form a straight line.
Cinch resistor networks to the PCB by bending the end pins over, one in one direction and the opposite
end the other direction. Then, solder a couple of pins and inspect to be sure you are happy with the
position. Straighten the bent-over pins and solder all remaining pins.
Next, you will install the sockets. Notice that 8, 14, 16, and 20 pin sockets of the same width are used. Be
certain not to place a shorter socket in the wrong location in place of a longer one. The number of pins are
indicated on the PCB. The PCB also indicates the end for the notch. Align the socket notch as marked on
the PCB. Bending two opposite corner pins is a good way to hold the socket to the PCB while soldering.
Solder the other two corner pins ONLY. Then check the socket flat on the PCB while it is still easy to
re-heat one pin and squeeze the socket to the PCB if it is not perfectly flat. Once you are certain the
socket is flat, solder the remaining pins.
Note: A special jumper is required at socket U6 if you have the MW2090 Miniwave PCB Rev 0. There is
a missing trace on this PCB. I assume that boards above Rev 0 have this error corrected. Please contact
John Blacet if you have specific questions. When installing socket U6, solder all pins except pins 1 and 5.
Before soldering pins 1 and 5, make a short jumper that will connect these two pins together along the
bottom of the board. I recommend an insulated jumper to avoid any possible shorts to the traces below.
I used a resistor lead covered with small heatshrink. [photo]
Next, you will install the transistors and voltage regulators. Notice the orientation (flat side) of each is
marked on the PCB. Be sure to face them in the correct direction. These devices will not be pushed all the
way down on the PCB. Leave ľ inch or less between the bottom of the transistor and the PCB. Cinch the
device by bending the outside leads, then solder the middle terminal only. Straighten the leads and
the transistor and solder the remaining two leads.
Next, you will install the remaining capacitors. All remaining capacitors are electrolytic and polarity must be
observed. Notice the PCB is marked with a "+" sign. The caps have "+" indicated by a longer lead and "-"
indicated by a stripe on the capacitor. Install all capacitors with the "-" stripe facing away from the "+" mark
on the PCB.
These are the last three components to be attached to the PCB with organic washable solder. After these,
you will be ready for your last board wash and a break.
OK. This is a good stopping point for another board wash. Run the board under warm water (do not use
any soap or cleaners). Gently scrub both sides of the board to remove the organic flux. This is our last
board wash. We will NOT use washable solder for the remainder of construction.
If you have not done so already, this would be a good point to inspect your solder joints. Check to be
certain you have not forgotten to solder one end of a component or that you have not accidentally bridged
one thing to another with excess solder. Verify the polarity of diodes, and electrolytic capacitors. Check
that the transistors and regulators are installed with the flat side as marked on the PCB.
Allow your PCB to dry completely, and put away that organic solder. All soldering from this point forward
will make use of no-clean solder. Your PCB should now look like this: [photo]
PART 3: Installing the trimmer pots and connecting wires to the PCB
The four trimmer pots are the last components to be soldered to the PCB. Notice that all 4 are different
values. Be certain to get the correct value in the correct location. Check their value with your meter if you
have any doubt. Donít forget to switch to no-clean solder.
Congratulations. You are complete with all soldering of components to the PCB. Up until this point, you
have basically built the PCB as if it were going behind the Blacet panel (except you did not attach the four
front panel pots or LEDs to the PCB). From this point forward, you will be departing considerably from the
Blacet version of the Miniwave to attach to the MOTM style front panel. I will assume at this point that you
already have your MOTM style front panel drilled and ready to go. I will also assume you have your bracket
trimmed and ready.
If you plan to implement my CV scale modification, this might be a good spot to install the two 82K ohm resistors. See the details in the CV modification instructionshere
Your next task, is to prepare the front panel controls for attachment to the PCB. Gather up your four 50 K
linear pots, one SPDT switch, one DPDT switch, and 8 LEDs. I wanted my "wave" and "bank" LEDs to be
different colors. So, I replaced four of the green LEDs supplied by Blacet with four red ones of the same
size (standard T1).
I decided as I prepared my front panel controls by attaching all the wires of the correct length to facilitate
the attachment to the PCBs. I also decided to adopt a color standard for the pot and switch numbers. I
highly recommend this. Throughout the remainder of these instructions, I will often refer to the colors I used.
However, you may select different colors. But, please write down your color strategy.
For my standard for pots and switches, I elected to use these colors (I used wire John supplied with the
kit): Pin 1 = blue, Pin 2 = red, Pin 3 = black. Please be aware that all of the wire lengths I specify in this
document assume a PCB mounted to the left (looking from the back). Opposite side mounting will change
these recommended lengths.
First, attach three wires to each 50 K panel pot. Be sure you have a backing nut for all four of the pots. If
you use pots intended for PCB mounting (as I did), use heat shrink to insulate the wires connected to the
pots. One pot should be fitted with wires about 4 inches long. Two pots should be fitted with wires about 3
inches long. One pot should have wires attached two inches long. You may wish to leave the leads about
one-half inch longer for trimming and stripping the ends for soldering. After I attach the wires to the pot,
I like to twist them together to the end to keep everything neat.
Each of the two switches must have wires attached. Like the pots, I used heat shrink to provide insulation
after I attached wires to the switch. Switch one is the SPDT switch. Attach 3 wires per the color standard.
These wires must be at least 8 inches long. Like the pots, I twisted all three wires to the end to keep
everything neat. We will have LOTs of wires on the back of this panel. Neatness will be important. My
switch was not marked. So, put the red wire on the middle terminal, and the blue and black each on one
of the end terminals (this will cause the colors to establish your switch terminal numbers)
Switch # 2 is a little more complicated because all of the wires do NOT go to the same location on the
PCB. Looking from the back of the switch, you need to call one side (row of 3 terminals) the "a" side and
the other side the "b" side. It makes no difference which side you choose. But, write it down.
For switch "a" you will attach all 3 wires. Following the standard, you will attach blue to terminal 1 (either
end - my switch was not marked). That wire must be about 8 inches long. The black and red wires need
only be 6 inches long. Attach the red wire to terminal 2 (center) and the black wire to the remaining end
terminal 3. The "b" side of the switch will have only 2 wires attached. Terminal # 1 will not have a wire.
On the "b" side, attach a 8 inch long black wire to terminal 3 (across from the black terminal 3 on he "a"
side. Attach a 10 inch long red wire to the # 2 (center) terminal. Apply heat shrink as needed to insulate
the wires on the back of the switch.
Now, here is the tricky part. When you twist the wires together, you will mix the "a" and "b" sides. This will
correspond to the locations for the wires to attach to the PCBs. First, twist only two of the wires from the
"a" side together. Twist the 6 inch red and black wires together. Leave the blue wire out. Next, twist the
remaining three wires together. That should be the 8 inch blue from the "a" side, the 8 inch black from the
"b" side and the 10 inch red from the "b" side. This will make more sense later.
All 8 of your LEDs must have wires attached. You must pay attention to polarity and assign a color code
so you are certain to hook them up correctly. Notice that one lead is longer than the other on the LED.
So, assign your colors based on lead length. Here is how I did it. For my four "bank" LEDs (I changed to
red ones), I attached a white wire to the long lead and a blue wire to the short lead. These wires should
be about 7 inches long. Write your colors down. For my green "wave" LEDs, I attached a red wire to the
long lead and black wire to the short lead. These wires should be about 5 inches long. You will need to
insulate your wire-to-LED connections with heat shrink.
There is no need to prepare any jacks for the front panel. We will actually start those wires from the PCB
end. Letís do that now. Attach 3 wires (I used black) to the "COM" connection by the power connector.
These leads must be at least 10 inches long. You will also attach four more wires to the jack connectors
on the PCB (J1, J2, J3 and J4).
I used a different color for each to make it easy to follow. The wires at J2, 3 and 4 (in a common location
on the PCB) should be about 9 inches long. I used blue for J2, yellow for J3, and red for J4. The wire
attached to J1 should be about 7 inches long. I used green.
Part 4: Attaching front panel controls and wiring to the PCB
Instead of trying to connect wires to the front panel after parts are attached to the panel (as common on
MOTM construction), you will wire everything except the jacks to the PCB and then attach to the front panel
when mounting the PCB. I think this is easiest for this module. And, that is why we prepared all components
You will start with the LEDs. I recommend tying the other wires back out of the way while making these
attachments. I used some wire ties to temporarily control the wires.
When connecting the LEDs, you must observe polarity. The "long" LED leads connect closest to the edge
of the PCB for all 8 LEDs. Notice the LEDs are numbered between the LED location and the resistor
network. Each group is also labeled to its bit significance of 1, 2, 4 or 8.
The LEDs 1, 2, 3, and 4 (between the pot locations R1 ad R2) are the "bank" LEDs. You will attach the
LEDs you prepared with the longer wire leads (red LEDs with red and black wire leads on mine). I trimmed
my leads to be a comfortable reach to the location on the front panel. I also slightly staggered the length
since some are closer. I made 8 the longest, 4 about ľ inch shorter than 8, 2 about ľ inch shorter than 4,
and 1 about ľ inch shorter than 2. When attaching the wires, I put my white leads closest to the edge at the
"anode" side as indicated on the PCB. My white lead corresponds to the "longer lead" on the LED before
I attached wire. Remember that I told you to write that down? What colors did you select? Be sure you put
yours so that the lead that was long on the LED is now attached to the terminal closest to the edge of the
The LEDs 5, 6, 7, and 8 (between the pot locations R3 ad R4) are the "wave" LEDs. You will attach the
LEDs you prepared with the shorter wire leads (green LEDs with blue and white wire leads on mine). I
trimmed my leads to be a comfortable reach to the location on the front panel. I also slightly staggered the
length since some were closer. I made 8 the longest, 4 about ľ inch shorter than 8, 2 about ľ inch shorter
than 4, and 1 about ľ inch shorter than 2. When you finish your LEDs your PCB should look like this.
Next, you will connect the pots. Be certain that the terminal numbers on the pots match those on the PCB.
Notice that terminal 1 is marked at each pot location. Following my color standard, blue goes to 1, red to
2 and black to 3 for each pot.
The switches are next. The connections are marked with the switch number and terminal numbers on the
PCB. For example, "S1-1" is switch 1 terminal 1. And, S2A3 is switch 2, side A, terminal 3.
When you are complete with your switch and pot connections, your PCB should look something like this.
Part 5: Attaching to front panel
You have many wires on your Miniwave panel now. I find it helpful to pull back and tie out of the way the
ones not being used. Front panel attachments will start with the pots. Two of the pots will hold the PCB
mounting bracket to the front panel. I am assuming you are following my lead to have the PCB on the left
side as you look from the back (MOTM style). Adjust accordingly if you have selected the opposite side.
Be absolutely certain to use the backing nuts on your pots. You cannot tighten against the pot. This will
ruin the pot.
When you finish the switches your PCB will look like this. [photo] You can see that I still have my LEDs tied
back out of the way to help with the wire clutter.
Next, you will wire the jacks. You have three long black wires attached to the "COM" point on the PCB by
the power connector. These are all attached to the same point, so it does not matter which one goes to
which jack. However, you will notice that we have only 3 wires but 4 jacks. Due to the distance between the
PCB connection and jacks, you may find it beneficial to tie these 3 wires together with wire ties for
neatness. All these wires will attach to the bevel of your front panel jacks.
The remaining 4 wires all attach to the terminal on the left side of the jacks (looking from back). Nothing
will be attached to the top terminals on any of the 4 jacks.
You now have everything attached to your panel except the LEDs. Your project should look something like
this. [photo] If you tied the LEDs out of the way, you should now untie them and form the leads around to
insert the LEDs in the front panel. The LEDs with the longer leads (from between the R1 and R2 positions)
go to the "bank" side of the panel. The numbers at the edge of the PCB (1, 2, 4 and 8) correspond to the
identification numbers on the panel. You will NOT be actually attaching the LEDs to the front panel at this
time. But, you will find that the stiffness of your wires and a couple of wire ties should be all you need to
relatively secure them in the positions they belong.
Insert the other four LEDs with the shorter wire-leads into the "wave" position in the same manner. These
LEDs connect from between the R3 & R4 positions on the PCB.
Congratulations. Your Miniwave should now look completed. [photo] [photo] Add your four knobs to the
panel pots. Your Miniwave is now ready for testing and calibration. Please refer to the Blacet documents
for testing and calibration. Once you are complete with testing and calibration and absolutely certain that
everything is functioning properly, you should can secure the LEDs to the front panel. The reason for not
securing the LEDs to the panel before testing is simple. Once you secure them, they can be removed.
But, it will be a somewhat troublesome affair best avoided if possible.
Of course, you can attach these LEDs to the front panel by a variety of methods. One person suggested
a strip of PCB with all the LEDs attached. The PCB is then secured at the ends to hold all the LEDs in
place. I could not find any off-the-shelf PCB material with the correct spacing to make that work for me.
Another method that apparently works well is to drill your holes slightly undersized for the LEDs. Then you
freeze the LEDs, but not the panel. Insert the frozen LEDs in the panel holes. Once they thaw and expand,
they are wedged in to the panel very well.
While this method might work well. It did not meet my construction method since I already have the LEDs
attached to the PCB. Therefore, here is the method I used and suggest:
After you are certain the LEDs and the rest of your Miniwave is working properly, the LEDs can be secured
into their holes using ordinary bathroom caulk. I would stay away from the silicon based products. I used a
DAP product called "ALEX PLUS" It is an acrylic latex caulk. Any latex based caulk should be fine. Also,
remember that when I attached wires to my LEDs I used heat shrink. So, all the conductor on the back of
my LEDs is completely insulated. However, this should not matter. I checked the dried caulk for conductivity
and found the resistance to be so high that it would not register on my DVM.
I like the caulk solution for a variety of reasons. But, probably the most significant is that if I need to replace
a LED, the procedure is relatively easy. After the caulk is dry, it can be easily cut with a razor or Exacto
knife to extract a single LED. Once the LED is replaced, the caulk can be easily patched on the back. Here
is what the LEDs look like ones the caulk is installed. [photo]
Now, if you have ever used caulk you know how difficult it is to install the stuff neatly. As you can see from
my photo, I have a nice neat box of caulk around my LEDs. The method to accomplish that is easy. Use 4
pieces of masking tape to outline the area where you want the caulk to be. Align all of your LEDs in the
holes they belong in. Squeeze your caulk out along both sides of the LEDs. Use you finger to push the
caulk between the LEDs as needed and to make an even distribution around the edges (and out onto the
masking tape. The caulk should be thick up around the LEDs so that you cannot see any of the actual
LEDs. However, it should be feathered out thin near the edge at the masking tape.
After you are satisfied that you have your caulk distributed to your liking, simply pull the masking tape off
carefully once piece at a time, revealing your neat clean edge. It will be helpful to have a couple of paper
towels handy to keep your fingers clean and to have a place to drop the tape that is messy with caulk.
You have plenty of time after the caulk is in place to adjust your LEDs to uniformity. The caulk takes a long
time to set up. After you have your LEDs aligned as you want them, set your module aside and give the
caulk several hours to firm up.
That concludes my instructions for assembly of the Blacet / Wiard Miniwave in the MOTM format using
Stooge panels and brackets. I hope my work has made the process more enjoyable for you and helped
you to achieve success. I always welcome feedback and constructive criticism. If you have any ideas for
improvement of this document, please drop me a note. Here are the completed photos.