Ramsey Electronics Treasure finder TF-1 Instruction Manual page 9

treasure finder kit, it is best to follow the step by step instructions. Try to
avoid the urge to "jump ahead" installing components.
Since you may appreciate some "warm-up" soldering practice as well as a
chance to put some "landmarks" on the PC board, we'll first install some of
the larger mounting components. This will also help us to get aquainted with
the up - down, left - right orientation of the circuit board. Remember that the
majority of the components will be mounted on the "component " side of the
circuit board and soldered on the "solder " side of the circuit board, the side
with the printed circuit traces. Have a look at the component layout diagram
to help with your assembly.
1. Install S1, the push-button switch. Be sure to push the part as close to
the circuit board as it will go, as the alignment of this part is important in
getting the case holes to line up with the part. Solder all six leads.
2. Identify and install the 10K trimmer potentiometer R11 (labeled 10K).
Gently "rock" the component into place before soldering. Be sure to
solder the mounting "tabs" into place to provide for a secure fit.
3. In the same manner, identify and install R7, another 10K trimmer
potentiometer. Be sure that both the "knob" ends of the pots line up
evenly for easy installation into the case.
4. Moving to the rear of the board, install J1,a PC mount miniature type
connector. Again, be sure to push the component firmly into place.
Solder all three connection points.
Now it's time to build the power supply portion of the circuit. We use a zener
diode regulation circuit for a voltage regulator to provide a stable source of
power for the circuit. Zener diodes exhibit a characteristic of a very specific
reverse biased "break down " voltage, and this property is exploited by wiring
the diode reversed biased with reference to the 9V supply. A 120 ohm
resistor is placed in series with the diode to limit the amount of current that is
allowed to pass through the zener.
5. Identify D3, the 6.2 volt zener diode (gray glass case with a polarity
"band" denoting the cathode (negative) side of the diode. Install as
shown in the parts placement diagram (D3 is adjacent to the battery
input terminals).
6. Install R13, 120 ohm (brown-
red-brown). Remember to save
a few of the snipped off
component leads to act as
LED
(-)
PC Board
(+)
TF1 • 9
Leave these leads
as long as possible