Inspire VLF-3 Assembly Instructions Manual

VLF-3 Assembly Instructions

1

INSPIRE VLF-3 Receiver Kit

Assembly Instructions

The following assembly instructions should be followed carefully. The INSPIRE VLF-3
receiver kit is NOT a simple electronic assembly. If you follow the instructions carefully you
should be successful in building a receiver that works. If you are not careful, you run the risk of
having a problem that is very difficult to locate and fix. Be careful, take your time, and GOOD
LUCK!

TOOLS NEEDED:

Philips head screwdriver
Small standard screwdriver
Wire cutters
Wire stripper
Soldering iron (15-25 watt, small tip)
Light duty resin core solder (60/40)
Sponge

Magnifying glass

Solder sucker or solder wick

KIT CONTENTS:

1. Black plastic enclosure

2. Face Plate

3. Printed Circuit Board (PCB)

4. Four bags of components:
Bag 1 resistors, inductors
Bag 2 capacitors
Bag 3 ICs, diodes, sockets
Bag 4 switches, jacks, knobs, antenna terminal, wires, misc. hardware

VLF-3 Assembly Instructions

2

Printed Circuit Board (PCB):

Faceplate

Front Control Panel

Component Side / Battery Side

All electronic components are inserted
from this side and soldered on the other
side. The battery holder is inserted
from this side also.

Switch Side

The four DPDT slide switches, the two
10k pots and the two LEDs are inserted
from this side and soldered on the other
side.

VLF-3 Assembly Instructions

3

R5

+

–

VLF-3 Assembly Instructions

4

ASSEMBLY SEQUENCE

1. Solder components to PCB.

2. Assemble jacks subassembly, connect wires to antenna terminal.

3. Connect wires to PCB.

4. Final assembly of receiver.

5. Test receiver.

(Check off boxes as each step is completed.)

 1. Solder components to PCB.

(NOTE: The transistor (Q1) and the field effect transistor (J-FET with ferrite bead) have been
preinstalled.)
 1a. Sort and install resistors.

Remove the resistors from Bag 1. Leave the
inductors for later installation.

The colored bands on the resistors indicate the resistance
using a color code. This table indicates how to convert each
color to its numerical equivalent.

0 black
1 brown
2 red
3 orange
4 yellow
5 green
6 blue
7 violet
8 gray
9 white

gold: 5% tolerance.

To read a resistor code, first locate the gold band and
read the colors in order from the other end. (All resistors in
this kit have a gold band indicating 5% tolerance.) The first
two bands indicate digits in the resistance, the third band
(called the multiplier) indicates the number of zeroes to be
added to the digits to obtain the resistance.
(NOTE: 1000 = kilo = k ; 1,000,000 = mega = Meg)

Bag 1 Contents

Resistors:

R1 560 kΩ
R2 10 Ω
R3 2.2 MegΩ
R4 22 MegΩ
R5 680 Ω
R6, R12 220 Ω
(R7, R26 10k pots in Bag #4)

R8 43 kΩ
R9, R17 10 kΩ
R10, R13 2.2 kΩ
R11 470 Ω
R14 100 kΩ
R15, R16, R20 20 kΩ
R18 15 kΩ
R19, R25, R27 100 Ω
R21, R22, R23, R24 1 kΩ
R28 270 kΩ

Inductors

L1 3.9 mH
L2 150 mH

Band 2

Band 3

Band 4
(gold)

Band 1

VLF-3 Assembly Instructions

5

What is the resistance for each of the following?

Example 1

Example 2

Example 3

Example 4

Band 1
Band 2
Band 3

brown

black

brown

yellow

violet

orange

red

black

green

orange
orange

orange
Band 1
Band 2
Band 3

1
0
1

4
7
3

2
0
5

3
3
3

Resistance

100
100 Ω

47000
47 kΩ

2000000
2 MegΩ

33000
33 kΩ

Use the resistor code to identify and sort all of the resistors. One good way to keep them
sorted is to tape one end to a piece of paper and write the resistance and component number (R1,
R2, etc.). Once you have identified and sorted all of the resistors, you are ready to solder them to
the PCB.

To prepare a resistor for insertion into the board, bend the two leads so that they form a
right angle to the resistor body.

Resistor locations on the component side of the PCB are indicated with the “R” number from the
parts list between the two holes for insertion of the leads.

Part of the PCB showing location of R1, R3, R4 and R6.

To install, place the leads of the resistor through the appropriate holes and press the
resistor down against the component side of the PCB. (There is no required orientation for
resistors. Either lead may be inserted in either hole.) Turn the board over while holding the
resistor in position and bend the leads slightly outward to hold the resistor in place and solder the
leads to the circuit side. (NOTE: There will be an empty resistor symbol on the PCB between
R15 and R20. No part will be installed in this location.)

VLF-3 Assembly Instructions

6

STEPS FOR SOLDERING RESISTORS, CAPACITORS AND WIRES:

IMPORTANT:

DO NOT leave a soldering iron plugged in for

a long time without using it.

NEVER leave a hot soldering iron unattended.

.

PCB

TRIM

PCB

Finished solder joint

Soldering iron

PCB

Touch solder to the side
of the lead away from
the soldering iron.

PCB

lead

contact

PCB

Press soldering iron
firmly down against the
contact and to the side
against the lead.

1. Clean the tip of the iron by wiping it on
the wet sponge.

2. Place a small amount of solder on the
tip.

3. Press the tip down against the circuit
contact and against the resistor lead and
hold for 5 seconds.

4. After the lead and the contact have
heated for 5 seconds, apply the solder to the
lead and contact (NOT directly to the iron)
until the solder melts and flows around the
lead and into the contact.

5. Apply enough solder to allow it to run
down along the lead. Do not apply so
much solder that it runs across the PCB
surface.

6. After enough solder has been applied (1­2 seconds), remove the solder wire but hold
the iron in place for another 2-3 seconds.

7. Remove the iron, allow the joint to cool
and inspect the joint.

8. Trim the excess lead wire just above the
solder joint.

Repeat this process for the remaining
resistors.

Leave soldering iron in
place for 1-2 more
seconds.