Bill of Materials
|1||DU-RDT DIY PCB|
|1||DU-RDT Front Panel|
|2||Alpha||SR1712F-0108||1P8T rotary switch|
|1||E-switch||TL1105DF160Q||13mm tactile switch|
|9||QingPu||PJ301M-12||3.5mm mono jack|
|2||74HC164N||8-bit shift register|
|1||74HC74N||dual D-type flip flop|
|5||LED, green 3mm|
|5||0.320" LED spacer|
|1||2 x 8 0.1" pin header|
|5||DIP-14 IC socket|
|2||Kobiconn||164-9008-E||IDC socket 16-pin|
|1||Amphenol||191-2801-116||28 AWG 16-cond. ribbon|
Our Mouser project cart has most of the necessary components.
Note that the rotary switches stocked at Mouser have a longer shaft than the ones shipped with the kit; this can be fixed with a Dremel, since they will be covered with knobs anyway.
The 74HC7014N buffer in DIP has been obsolete for some time, and as of 2017 is becoming difficult to acquire. No drop-in replacement appears to exist. An alternative is to purchase the 74HC7014D in SOIC, and use a SOIC-14 to DIP-14 adapter. If you are not comfortable with a small amount of SMT soldering, or simply want the convenience, an adapter with pre-soldered IC can be ordered from Proto Advantage using Digikey part number 1727-6342-1-ND.
Check that your kit contains all of the parts listed in the BOM above before starting. All components of the DU-RDT are through-hole parts, and the placement is largely obvious from the drill footprint and silkscreen. Pay attention to the resistor values and the orientations of the diodes, LEDs, and ICs. The soldering order is not critical; the suggested order tries to make it easy to solder some of the more tightly spaced components while adding the more fragile semiconductor components later in the process. Note that the 78L05 is optional, and should not be populated when using the 16-pin bus header.
Step 1: Eurorack bus header
The 16-pin Eurorack bus header is the only component soldered to the back of the PCB, as indicated by the silkscreen outline. Solder this header first, as shown. Make sure it is flush against the PCB.
Optional: If you do not have a 5V rail on your Eurorack bus, you may use a 10-pin header, soldered to the bottom 5 pairs of pads, and add a 78L05 voltage regulator in TO-92 package (not supplied in the kit) where labeled.
Step 2: Register delay selector switches
Solder the two large 8-position rotary selector switches to their positions at the top-center of the PCB. The curved spring portion should be oriented upward. Solder the side tabs first, then the pins.
Step 3: Pattern lock switch
Solder the 6-pin pushbutton switch to its position directly below the two selector switches. It has a locator peg that should fit the corresponding hole in the PCB to ensure correct orientation. Make sure it is flush against the PCB.
Step 4: IC sockets
Solder all five 14-pin DIP sockets. Ensure that the notched end of the sockets are oriented according to the silkscreen, and that they are flush against the PCB.
Step 5: Decoupling capacitors
Solder all five decoupling capacitors. Their orientation is not important.
Step 6: Resistor identification
The next step is to begin soldering the resistors, so at this point, take a moment to gather, identify, and sort the resistors in the kit according to the following chart matching color bands to values.
Check the resistances with a multimeter if unsure.
Step 7: Resistors
All resistors are mounted vertically, with one lead curved in a U shape so that it is parallel to the other lead. The resistor body (i.e. the straight lead) will sit in the circle marked on the silkscreen. Make sure that the curved leads will not contact the inner surface of the panel! You can use one of the 3.5mm jacks as a guide: the top of the resistor lead should not protrude beyond the height of the black plastic.
Step 8: Diodes
Solder all six 1N4148 diodes. They should be oriented such that the stripe on the diode aligns with the stripe on the silkscreen.
Step 9: Tactile switch
Solder the 13mm tactile switch in the top left corner of the PCB. Its orientation is not important.
Step 10: Input jacks
Solder the four input jacks along the left side of the PCB. Ensure that they are flush against the PCB.
Step 11: LEDs
Insert the LEDs into their spacers and solder to the locations shown. Ensure that the long (positive) lead is oriented according to the + symbol on the silkscreen. When soldering, take care to keep the LEDs straight and vertical, and make sure there is snug contact between the PCB surface, spacer, and bottom surface of the LED body.
Step 12: Transistors
Solder the five 2N3904 transistors to the locations shown, ensuring the orientation matches the silkscreen.
Step 13: Output jacks
Solder the five output jacks along the right side of the PCB. Ensure that they are flush against the PCB.
Step 14: IC seating
Insert each of the five ICs to the correct socket on the PCB (the part number visible on the silkscreen through the socket should match the part number on the IC). Ensure that the orientation is correct; the notched end or the end marked with a dot should be aligned with the notched end of the socket.
Step 15: Front panel
Carefully place the front panel over the switches, jacks, and LEDs. Screw the supplied washer and nut onto each of the two rotary switches and tighten them down. Screw the supplied knurled nuts onto each of the 3.5mm jacks and tighten them down. Add the D-shaft knobs to the rotary switches and press down carefully until they are fully seated. Add the black switch cap to the pushbutton switch and press down until it snaps on fully.
Step 16: Power cable
Tightly crimp the IDC connectors to the ends of the ribbon cable as show in the image, ensuring that the key is facing inward, and that the arrow aligns with the red stripe. Fold the ribbon cable back over the top of the connector, and snap on the strain relief clip.