Universal Keying Adapter 3
05/05/2013
Page 2 of 10
Parts List
Part Name
Part Description
K1
Optically isolated, MOSFET Solid-State Relay (6-pin DIP or SMT package)
NOTE: May be 4-pin inline with high voltage/current option
Q1
2N7000 MOSFET
C1
10 or 100 µF, 16V electrolytic capacitor
R1
470 Ohm ¼ W resistor (Yellow-Violet-Brown)
R2
220 Ohm ¼ W resistor (Red-Red-Brown)
R4 – R6
1 K Ohm ¼ W resistor (Brown-Black-Red)
R3
100K Ohm ¼ W resistor (Brown-Black-Yellow)
D1
4.7V Zener diode (the larger glass diode)
D2 - D6
1N4148 diode (the smaller glass diodes)
POWER
2.5mm / 5.5mm coaxial power connector
SW1
Pushbutton power switch with round cap
LED
Dual PCB-mount LED indicators
INPUT
PCB-mount 3.5mm stereo jack
OUTPUT
RCA (phono) output connector
PCB
Printed Circuit Board
Assembling the Kit
Always use good static prevention practices when working with static sensitive parts (in this kit,
those are Q1 and K1). This means you should wear a grounding strap when possible, or work on
a static-dissipative work surface. Use a grounded tip soldering iron if possible. When soldering
small parts it is a good idea to use a fine-tipped, small pencil-type soldering iron of no more than
30 Watts or so. Use pliers, clamps or alligator clips as heat sinks to prevent heat damage to parts
while soldering. If you are not fairly experienced with soldering small parts, you may want to
practice on some scrap parts first or get some help from a more experienced builder.
All parts should be installed from the top (white printed) side of the printed circuit board. As you
install each component, bend the leads slightly if needed to help hold the part in place. It’s a
good idea to use pliers, an alligator clip or some other heat sink to keep from damaging
components with too much heat from soldering. Solder the leads in place, being careful not to
use too much solder. Using a pair of fine-tipped diagonal cutters, neatly clip the component leads
close to the solder joint. Except where noted, make sure that the part is seated against the PCB
before soldering. This is especially important for the connectors and LEDs; if they’re not
installed right, the cabinet end panels will not fit properly.
Circuit Board Assembly
Note:
You can build your UKA-3 without connectors, switch or LED indicators if you wish to
integrate it into your own gear. An example would be for mounting the UKA-3 inside an existing
or new design tube amplifier or transmitter. The JP1 connector can be used to connect to your
own gear without using the connectors. See the section below entitled, “Using JP1”.
