Synthesis Technology MOTM-485 GX-1 Diode VCF Quick start guide

MOTM-485 GX-1 Diode VCF
Assembly Instructions & Owner’s Manual
Synthesis Technology
6625 Quail Ridge Dr.
Fort Worth, TX 76180
[phone]
www.synthtech.com
Aug. 11, 2005

MOTM-485 PARTS LIST
Please carefully check that all parts are in your kit. If you have a suspected shortage,
please call or email. If you get free extra stuff, keep it for next time.
Capacitor bag, containing the following 12 parts:
3ea 10µfd, 50V Electrolytic C1, C2, C3
2ea 22N reddish-brown film cap (marked 223) C10, C11
1ea 47N reddish-brown film cap (marked 473) C12
1ea 3M3 50V non-polar electrolytic C9
1ea 33µfd 16V non-polar electrolytic C6
2ea 10µfd, 50V non-polar electrolytic C7, C8
2ea 0.1µfd, axial ceramic cap (marked 104) C4, C5
Resistor bag, containing the following 50 parts:
9ea 100K 1% (brown, black, black, red) R1-R6, R14, R28, R35
5ea 4K7 (yellow, violet, red) R33, R41, R42, R43, R46
4ea 22K1 1% (red, red, brown, red) R19, R20, R24, R50
4ea 10K (brown, black, orange) R25, R45, R47, R49
3ea 2K2 (red, red, red) R18, R21, R22
3ea 18K (brown, gray, orange) R17, R27, R29
2ea 120K (brown, red, yellow) R9, R13
2ea 51K1 1% (green, brown, brown, red) R7, R8
2ea 47K (yellow, violet, orange) R15, R32
2ea 6K8 (blue, gray, red) R26, R30
2ea 1K 5% (brown, black, red) R34, R37
2ea 3K3 (orange, orange, red) R38, R44
2ea 150K (brown, green, yellow) R39, R40
1ea 200K (red, black, yellow) R10
1ea 470K (yellow, violet, yellow) R12
1ea 54K9 1% (green, yellow, white, red) R16
1ea 1K2 (brown, red, red) R23
1ea 470 ohms (yellow, violet, brown) R31
1ea 15K (brown, green, orange) R36
1ea 47 ohms (yellow, violet, black) R48
1ea 1K 1% 3300ppm Tempco resistor (black) R11 (mounts on Q1, see text)
IC bag, containing the following 11 parts:
3ea BC550C NPN transistor Q3, Q4, Q9
2ea BC560C PNP transistor Q2, Q6
2ea CA3086 transistor array IC Q7, Q10
1ea BF245 FET transistor Q8
1ea LT1013 op amp U1
1ea THAT 340P transistor array Q1
1ea SSM2220P PNP array Q5
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Misc #1 bag, containing the following 7 parts:
2ea Axial ferrite beads (plain, gray things) L1, L2
1ea MTA-156 power connector JP1
1ea SPDT toggle switch SW1
1ea DPDT toggle switch SW2
1ea 2K Bourns 3386P-202 trim pot TP1
1ea 20K Bourns 3386P-203 trim pot TP2
 Knobs, 3ea, ALCO PKES90B1/4
 Jacks, 6ea Switchcraft 112A
Pots, 3ea containing the following (either part will work):
3ea 100K lin Spectrol 149-71104/148-71104 VR1-3
 Front panel
Printed Circuit Board
Mounting bracket
Wire bag, containing the following 10 wires:
1ea long RG-174 coax J4
2ea short RG-174 coax J5, J6
1ea 2-wire set 22ga. (white/black) long J3
1ea 2-wire set 22ga. (orange/white) long J1
3ea 3-wire set 22ga. (orange/white/gray) short SW1, SW2
1ea 2-wire set, 22ga. 3½” (red/black) J2
1ea Power Cable, 20”
Hardware bag, containing:
4ea #8-32 x 3/8” black screws (for mounting module to rack)
4ea #6-32 x ½” zinc screws (for attaching pc board to bracket)
4ea ¼” aluminum spacers
4ea #6 KEPS nuts (for pc board)
5ea small tie-wraps
Organic Solder AND No-Clean solder (1 bag each type)
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GENERAL INFORMATION
Thank you for purchasing the MOTM-485 VCF. If you have any issues concerning the
building or use of the kit, please contact us at [phone] or by email:
[email protected].
This kit should take the average builder between 2 to 3 hours. However, please remember
this is NOT a speed contest; it is an accuracy contest. There is no rule that you have to
complete the entire kit in one day (as long as you wash the flux off!).
Successful kit building relies on having the proper tools. Here is a list of what you will need
to build your MOTM-485:
• Soldering iron, 50W max power. Use 700ºF tip/temperature setting
• Small amount of heatsink compound (not supplied)
• Needle-nose or chain-nose pliers
• Mouser lead-bending jig for the resistors
• Diagonal cutters
• Allen key set for securing the knobs (1/16” or 1.58mm)
• Magnifying glass to read the markings and to inspect solder joints
• DVM (Digital Volt Meter) to verify resistor values
• #1 Philips screwdriver
• Fingernail brush for washing off the organic flux
• Old towel for blotting dry pc board
For more information of tools used and suggestions, see the MOTM FAQ and Tutorial pages
at http://www.synthtech.com.
The 2 trimmers on the board are set “by ear”, no special test equipment needed. An
oscilloscope is handy (and fun) to look at the output waveform, seeing the effects the VCF
has using various settings.
HOW TO FOLLOW THE DIRECTIONS
Please read the entire instruction before proceeding. There may be valuable information at
the end of the instruction. Each instruction has a check box next to it. After you
complete the instruction, check the box. This way you can keep track of where you are in
the process.
Note that this kit uses 5 different decades of 47-ohm resistors, be careful and don’t get them
swapped! Also, don’t swap the 2 trim pots (they are clearly stamped on the sides in black
ink). The 1% resistor color bands can be confusing, so always measure them with the DVM
before soldering.
VERIFY THE PARTS LIST
 Verify that all of the parts are in the kit as shown on the parts list.
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A WORD ON SOLDERING
There are 2 very different types of solder used in the kit. Most of the soldering uses
“Organic Flux” solder. This is strictly for use on the pc board, and is NOT to be used
on the front panel wiring!
In order for solder to “stick” to the copper, a chemical called “flux” is embedded in the
solder. The flux leaves a residue on the pc board that should be cleaned with warm water.
DO NOT USE SOAP OR OTHER CLEANSERS. Most of the parts in the kits are
“waterproof” and can be washed in the sink. The flux is OSHA approved for flushing down
the drain, so don’t worry about that! A soft brush is used to gently scrub the board. We
recommend a “fingernail brush”, which is about 1 x 2 and can be found for about $1.
The other type of solder is called “No-Clean Flux”; because as the name implies, it does not
require washing. This solder is used for wiring the pots, switches, jacks, etc. This solder is
harder to use on the pc board because even when melted, it is not very fluid (about the
consistency of toothpaste). We will use it VERY SPARINGLY on the pc board.
OK, let’s get started on the board!
PART #1: SOLDERING THE RESISTORS
 Find the MOTM-485 blank pc board. There is a copy (larger than actual size) of the
silkscreen which shows where the parts go at the end of this document. It will be
useful if you locate the part on the print first, put the part in the board, then “check
off” the silkscreen. All parts are inserted from the side of the board with the white
silkscreen (the “top” side).
We will stuff the resistors by value to make things easier. The resistors are inserted
on a 0.4-inch spacing (this is where the Mouser jig makes things nice and fast). The
important thing is to be sure that the part is sitting all the way down on the board.
Push the leads in the holes, push the part on the board, and then bend the leads on
the bottom outwards to a 45-degree angle (roughly!). This is called “cinching the
leads”: and keeps the part from falling out! From the bottom of the board, solder
(using the organic flux), applying heat to the pad for about a half second first, then
applying just enough solder to make a small puddle that looks like a tiny pyramid.
Enough solder should flow in the hole such that on the top (component) side, a small
amount is on the top pad as well
The rule of soldering: don’t use too much, you can always add more! Cut the leads
flush with the top of the solder joint with your diagonal cutters.
Locate the 100K 1% resistors (9) and solder into R1 to R6 (all near U1), R14 (by J3),
R28 (by Q7) and R35 (by VR3).
Locate the 4K7 resistors (5) and solder into R33 (by C6), R41-43 (by TP2) and R46
(by SW2A).
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Locate the 22K1 1% resistors (4) and solder into R19 (by Q5), R20 (by L2), R24 (next
to Q5) and R50 (by C11).
 Locate the 10K resistors (4) and solder into R25 (by Q7), R45 (by Q2/Q3), R47 (by
Q8) and R49 (by Q10).
 Locate the 18K resistors (3) and solder into R17 (next to R49 that you just did), R27
(by J1) and R29 (2 over from R27).
 Locate the 2K2 resistors (3) and solder into R21 and R22 (by C3) and R18 (by Q9).
Locate the 120K resistors (2) and solder into R9 (by TP2) and R13 (by Q8).
Locate the 51K1 1% resistors (2) and solder into R7 and R8 (by U1).
Locate the 6K8 resistors (2) and solder into R26 (by Q1) and R30 (close to SW1).
 Locate the 1K 5% resistors (2) and solder into R34 and R37 (by C7/C6).
Locate the 47K resistor (2) and solder into R15 (by SW2B) and R32 (behind VR2).
 Locate the 3K3 resistors (2) and solder into R38 (by Q9) and R44 (by C11/C12).
 Locate the 150K resistors (2) and solder into R39 and R40 (by C10).
 Locate the 200K resistor and solder into R10 (by TP2).
 Locate the 1K2 resistor and solder into R23 (by J4).
Locate the 470K resistor and solder into R12 (by C12).
 Locate the 54K9 1% resistor and solder into R16 (by Q1).
Locate the 470-ohm resistor (look closely!!) and solder into R31 (by VR2).
Locate the 15K resistor and solder into R36 (by SW1).
Locate the 47-ohm and solder into R48 (by Q8). Leave the Tempco resistor for a
later step.
After soldering all the resistors wash and dry the pc board.
PART #2: Soldering the ICs & Misc parts
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Almost done with the parts on the pc board! This will finish up the soldering with the
organic flux.
Locate the MISC #1 bag and the IC bag.
Locate the ferrite beads (2). They are axial parts, gray colored with no markings.
These are non-polar, and are soldered into L1 and L2.
Locate the MTA-156 power connector. Solder into JP1. Note that the connector has
a “locking tab” on one side. This side is the “inside” facing relative to the pc board.
Note the silkscreen symbol for JP1 has a line on one side, indicating this is the side
where the locking tab goes.
Locate the LT1013 IC. Solder into U1, with the “dimple” on the top of the package on
Pin 1. Pin 1 has a square pad (all the others are round),
Locate the THAT 340P transistor array and solder in Q1. There is a “dimple” by
Pin 1.
Locate the SSM2220P and solder into Q5. The “notch” depression on the top of the
package matches the “notch” on the white silkscreen symbol.
Locate the CA3086s (2) and solder into Q7 and Q10 (match the “notches”).
Locate the BC550C transistors (3) and solder into Q3, Q4 and Q9. The flat side of
the transistor matches the flat side of the white silkscreen symbol.
Locate the BF245 FET transistor and solder into Q8. Note the center lead is angled
backwards slightly.
Locate the BC560C transistors (2) and solder into Q2 and Q6.
Apply a small bit of solder to the via holes. These are the small pads (no components
go in them) that allow traces to “change sides” of the pc board. DO NOT SOLDER
PADS FOR THE REMAINING COMPONENTS!! The via holes need a VERY
SMALL AMOUNT of solder. For example, there is a via hole on the top-side trace
that is above TP2, running along the edge of the board (by the “R9” white
silkscreen).
PART #3: BOARD WASH #2
Wash the board in warm water, gently scrubbing both sides.
Shake the board a couple of times, blot dry with an old towel (the leads will frazzle
a good towel). Let dry at least 15 minutes.
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 Take another break or set the kit aside for later. You are about 75% finished at this
point: this is a good stopping-point.
You are now finished with the Organic Flux solder. All soldering past this point is
using the No-Clean solder. You do not have to wash the board anymore.
PART #4: CAPACITORS/TEMPCO RESISTOR
Locate the CAPACITOR bag. Locate the 1K Tempco resistor, and your heat-sink
compound.
 Locate the 22N caps (2). They will have 223 stamped on the side. They solder into
C10 and C11.
Locate the 47N cap, with 473 stamped on the side. Solder into C12.
 Locate the 0.1µf axial ceramic caps. They solder into C4 and C5 (by U1).
Locate the 3M3 non-polar cap, and solder into C9 (by J2).
 Locate the 33µf non-polar cap. Solder into C6.
Locate the 10µf non-polar caps (2). Solder into C7 and C8.
Locate the 10µfd electrolytics (3). Note that there is a stripe on the NEGATIVE
terminal. The pc board has a + on the POSITIVE terminal. Carefully stick the
capacitors into C1, C2 and C3 with the stripe away from the + pad on the board.
Locate the black Tempco resistor. This will solder on top of Q1. A small amount of
heatsink compound is first applied to the top of Q1 and the Tempco is placed so that
the DIP package is in contact with the bottom of the Tempco. Be sure the Tempco is
level and flat before soldering.
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PART #5: FINISHING THE PCB (Trimmers, pots and wire)
You will now solder in the remaining parts on the pcb in preparation for wiring to the front
panel. USE THE NO-CLEAN SOLDER. BE CAREFUL!
 Locate the 2K blue trim pot. It will have “P 202” marked on one side. Solder into
TP1 (labeled Q TRIM).
Locate the 20K trim pot. It will have “P 203” marked on one side. Solder into TP2
(labeled CV OFFSET).
 Locate the Spectrol pots (3). IMPORTANT: in order for the pc board to properly
align with the front panel, each pot must be absolutely flat on the pc board, with
the shafts pointing away from the pc board. These are marked on the top side as
71104. Solder these pots into VR1, VR2 and VR3. Remove the outer pot nut and the
flat washer. The rear pot nut should be tightened all the way back, then rotated ¼
turn looser. This allows the stress of mounting to be on the threads of the bushing,
not pressing against the pot body itself.
Locate the WIRE bag. The MOTM-485 has lots of wires: be very careful when
soldering to the pc board in order that the wire colors are correctly into the proper
holes.
 The long coax wire solders into J4. A tie-wrap is used on each wire to secure the coax
flat onto the pc board. Note that the coax wires have one end stripped back shorter
than the other: the short end solders to the pc board. See the photo below for details
(this is a generic photo!)
Solder the 2 short coax cables into locations J5 and J6. Secure with tie-wrap.
Solder the long white/black twisted wire into J3. White into 1, Black into 2.
Solder the orange/white twisted wire into J1. White into 1 and Orange into 2.
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Solder the 3 white/gray/orange wires into SW1 and SW2A/SW2B. In all cases, the
White goes to 1, the Gray into 2 and the Orange into 3.
Solder the red/black twisted wires into J2. The Red is in 1 and the Black solders into
2.
YOU ARE NOW FINISHED WITH THE PC BOARD WORK!
BREAK TIME.
PART #6: FRONT PANEL PREPARATION
You will now attach components to the front panel. It is HIGHLY recommended that you
use a set of hollow-shaft nut drivers, NOT PLIERS, to tighten the nuts. This prevents
scratching. NOTE: all references to part orientation is from the REAR of the panel.
Locate the 6 Switchcraft jacks. Notice that from the rear, there is a beveled corner.
This corner is ALWAYS CONNECTED TO GROUND. Each jack has a flat washer, a
lockwasher, and a ½” hex nut. Remove the nuts and washers from each jack. Place
aside. Keep the lockwasher on the jacks.
Insert the 6 jacks/lockwashers, with the beveled corner in the upper-right corner,
into the 6 holes. Place the flat washer on the jack, then the hex nut. Hold the jack
with one hand on the backside, keeping it “square”. Tighten the hex nut with a nut
driver. NOTE: when tight, not much of the exposed threads of the jack are exposed.
You are now ready to attach the pc board to the bracket and then wire up to the panel.
PART #7: ATTACH PC BOARD TO BRACKET/PANEL
In the HARDWARE bag, locate 4 #6-32 x ½” screws, 4 #6 KEPS nuts, and 4 spacers.
Locate the mounting bracket. The pc board attaches to the bracket, with the 4
screws threading from the top of the board, through the spacers, through the
bracket, and then out the bottom of the bracket. The #6 KEPS nuts attach on the
bottom of the bracket. Note the bracket has 2 notches; these are for the 2 switches to
mount in-between the pots.
Attach the pc board to the bracket using the 4 screws, spacers and nuts (the nuts go
on the bottom of the pc bracket). Do not tighten the nuts all the way, so the pcb can
“slide” in the bracket. Next, place the 3 pot bushings/shafts through the 3 holes in
the panel. With the 4 pcb nuts still partially tightened, put the 3 flat washers and 3
nuts on VR1-V3 (on the front of the panel) and tighten. This will “pull” the pcb up
against the panel, resting on the 3 rear pot nuts. NOW you tighten the 4 nuts on the
bottom of the pcb bracket.
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