AAØZZ EZKeyer III 23 November 2014
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Copyright 2014 AAØZZ
Figure 4.7 – Four Corner Wires on Front Side
___ Install the 18-pin DIP socket for U1. Make sure the socket is oriented with the notched end
“up”, as shown on the silkscreen. Make sure all pins are all the way down in the board by first
soldering one corner pin and then reheating this pin while pressing down on the PCB right around
the socket. Often you will hear a “snap” as the pins all seat themselves all the way. Verify the
socket is mounted with the notch end oriented correctly and then solder the remaining 17 pins.
___ Install the three stereo jacks on the PC board. Solder one pin of each jack first. Make sure
the jack is flat on the board by holding the board sideways and pressing down on the jack as you
reheat the soldered connection. Then solder the other two pins. Repeat this procedure for the
other two jacks.
___ Install capacitor C1, located just above the 18-pin DIP socket. Solder.
___ Locate and identify diodes D1, D2 and D3. Notice the differences. D1 and D2 are the small
glass diodes (1N4148) while D3 is the black body diode (1N5817) with white markings.
___ Install diodes D1 and D2 (1N4148), the small glass diodes. Make sure the banded ends of the
diodes are installed per the silk-screen markings.
___ Install D3, the Schottky diode (1N5817), the black diode with white markings. Make sure the
banded end of the diode is installed per the silk-screen markings.
___ Install Q1 and Q2, the two BS-170 MOSFET transistors. Make sure the flat sides of these
transistors are installed per the silk-screen markings. Mount with the bodies of the transistors
about 1/4” above the PC board.
___ If you are going to be installing the standard on-board speaker (piezo) install it now. Solder
quickly and carefully, observing the polarity as marked. If you will be installing the optional
speaker, you can install it later.
___ Install the 4-pin header in HDR1. Solder.