5
Install trimmers R1 and R2 (5 k) as indicated by their component outlines on the top side of the board.
Install resistor network RP1 (3.9 k, 8 pins). This resistor network is symmetrical and can be installed
in either orientation, but for consistency you should orient it with the pin 1 end (black dot) toward pin 1 of
the PCB outline (round pad, also labeled "1").
Install the miniature slide switch, S1. The switch should be pressed down onto the board as far as it
will go before soldering. Use a minimum amount of heat to avoid melting S1's plastic body.
Set S1 to the
OUT
position.
Locate the 18-pin IC socket. One end will have a notch or other mark indicating the pin 1 end. Install
this socket at U2, with the pin 1 end of the socket toward the notched end of the IC's PC board outline.
Install the ceramic resonator, Z1. (Z1 looks like a capacitor with three leads.)
i
Before handling ICs and transistors, touch an unpainted, grounded metal surface.
Install transistors Q1, Q2, and Q3 (J309) as indicated by their outlines. The installed height of the
transistors should be no more than 3/8" (9 mm). Use a minimum of soldering time (1-2 seconds per lead).
Voltage regulator U4 (ZR78L06C) has a 3-pin TO-92 package, like a transistor. Install U4 in the same
manner as Q1-Q3.
Install the quad op-amp IC, U1 (LM837N). Orient the notched or dotted end of U1 toward the notched
end of its PC board outline (pin 1 end, to the left). Double-check the orientation before soldering.
The real-time clock IC, U3 (NJU6355ED), must be handled carefully
. Be sure to touch a grounded
surface before and during its installation.
Install U3, noting the orientation of the notched end as you did
with U1. Verify the orientation before soldering.
Install C5 and C6 (.022 µF, "223"). C6 may be a tight fit due to its proximity to U1. Adjust C6's
position slightly if necessary, but be careful not to stress the leads.
Install the 2-pin male connector on the top side of the board at W1 as shown below. The short ends of
the pins are inserted into the board, and the long ends face up. Do not solder yet.
W1
P2
P1
