Elenco XP720 User Manual
POWER SUPPLY KIT
MODEL XP-720K
Assembly Manual
Copyright © 2012, 1998 by ELENCO®All rights reserved. Revised 2012 REV-G 753269
No part of this book shall be reproduced by any means; electronic, photocopying, or otherwise without written permission from the publisher.
ELENCO
®
PARTS LIST
If you are a student, and any parts are missing or damaged, please see instructor or bookstore.
If you purchased this kit from a distributor, catalog, etc., please contact Elenco®Electronics (address/phone/email is at the back of this manual) for additional assistance, if needed. DO NOT contact your place of purchase
as they will not be able to help you.
RESISTORS
Qty. Symbol Value Color Code Part #
r 1R5 .18Ω 5% 3W 101804
r 2 R3, R4 2.7Ω 5% 1/4W red-violet-gold-gold 112701
r 2 R1, R2 150Ω 5% 1/4W brown-green-brown-gold 131500
r 2 VR1, VR2 2kΩ Potentiometer 192422
CAPACITORS
Qty. Symbol Value Description Part #
r 5 C1 - C4, C8 10μF Electrolytic 271045
r 2 C5, C6 2200μF Electrolytic 292226
r 1 C7 4700μF Electrolytic 294744
SEMICONDUCTORS
Qty. Symbol Value Description Part #
r 4 D1 - D4 1N4001 Diode 314001
r 4 D5 - D8 1N5400 Diode 315400
r 1 Q1 A70 Transistor 320070
r 1 Q2 2N6124 Transistor 326124
r 1 IC1 LM-317 Integrated Circuit 330317
r 1 IC2 LM-337 Integrated Circuit 330337
r 1 IC3 LM-7805C Integrated Circuit 337805
MISCELLANEOUS
-1-
Qty. Description Part#
r 1 Transformer 440720
r 1 PC Board 512013
r 1 Fuse 1A 530100
r 1 Rocker Switch 541204
r 1 Cover 611120
r 1 Chassis 612012
r 1 Heat Sink 615010
r 2 Knob 622009
r 1 Strain Relief 624003
r 5 Insulator Washer 624007
r 4 PC Board Stand-off 625001
r 2 Black Binding Post 625031
r 7 Int. Lockwasher, Binding Post 625031LW
r 7 Nut, Binding Post 625031HN
r 2 Red Binding Post 625032
r 3 Yellow Binding Post 625034
r 5
Screw 6-32 x 3/8” Phillips, Pan, Machine
641640
r 2
Screw 8-32 x 3/8” Phillips, Pan, Machine
641840
r 4
Screw 6 x 3/8” black, AB, Phillips, Truss
642652
r 2 Screw 6 x 3/8” black, AB, Phillips, Pan 642660
Qty. Description Part#
r 2 Nut 7mm 644101
r 4 Nut 6-32 Small 644601
r 2 Nut 8-32 644800
r 1 Nut 6-32 644600
r 2 Flat Washer 8mm x 14mm 645101
r 2 Lockwasher 5/16” 646101
r 2 Lockwasher #8 646828
r 4 Rubber Feet 662003
r 1 Fuse Holder (Upper Body) 663005UB
r 1 Fuse Holder (Lower Body) 663005LB
r 1 Fuse Holder (Hex Nut) 663005N
r 1 Fuse Holder (Washer) 663005W
r 3 Mica Insulator 780002
r 1 Silicon Grease 790005
r 6” 20 Ga. Red Wire 813210
r 48” 22 Ga. Red Wire 814201
r 48” 22 Ga. Orange Wire 814310
r 48” 22 Ga. Blue Wire 814610
r 1 Line Cord 862105
r 2” Shrink Tubing 1/2” Dia. 891101-2
r 1.5” Shrink Tubing 3/4” Dia. 899110-2
r 1 Solder Lead-Free 9LF99
Screw Identification
6-32 x 3/8”
Phil., Pan, Machine
8-32 x 3/8”
Phil., Pan, Machine
6 x 3/8” Black
AB, Phillips, Pan
6 x 3/8” Black
AB, Phillips, Truss
-2-
PARTS IDENTIFICATION
Resistor 2kΩ Potentiometer Capacitor Diode Transistor
Integrated Circuit Transformer PC Board Fuse
Heatsink
Switch
Knob
Strain Relief
PC Board Stand-off
Binding Post Assembly Fuse Assembly
Flat Washer Lockwashers
MicaNuts
7mm
6-32 / 8-32
#8 5/16”
Binding Post
Lockwasher
Nut
.18Ω 3W Resistor
-3-
Warning:
If the capacitor is
connected with
incorrect polarity, it
may heat up and
either leak, or
cause the capacitor
to explode.
IDENTIFYING RESISTOR VALUES
Use the following information as a guide in properly identifying the value of resistors.
BANDS
METRIC UNITS AND CONVERSIONS
Abbreviation Means Multiply Unit By Or
p Pico .000000000001 10
-12
n nano .000000001 10
-9
μ micro .000001 10
-6
m milli .001 10
-3
– unit 1 10
0
k kilo 1,000 10
3
M mega 1,000,000 10
6
1. 1,000 pico units = 1 nano unit
2. 1,000 nano units = 1 micro unit
3. 1,000 micro units = 1 milli unit
4. 1,000 milli units = 1 unit
5. 1,000 units = 1 kilo unit
6. 1,000 kilo units = 1 mega unit
IDENTIFYING CAPACITOR VALUES
Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads), or μF (microfarads).
Most capacitors will have their actual value printed on them. Some capacitors may have their value printed in
the following manner. The maximum operating voltage may also be printed on the capacitor.
Second Digit
First Digit
Multiplier
Tolerance*
Note: The letter “R”
may be used at times
to signify a decimal
point; as in 3R3 = 3.3
103K
100V
The letter M indicates a tolerance of +20%
The letter K indicates a tolerance of +10%
The letter J indicates a tolerance of +5%
Maximum Working Voltage
The value is 10 x 1,000 =
10,000pF or .01μF 100V
*
Electrolytic capacitors have a positive
and a negative electrode. The
negative lead is indicated on the
packaging by a stripe with minus
signs and possibly arrowheads. Also,
the negative lead of a radial
electrolytic is shorter than the positive
one.
Polarity
marking
BAND 1
1st Digit
Color Digit
Black 0
Brown
1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9
BAND 2
2nd Digit
Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9
Multiplier
Color Multiplier
Black 1
Brown 10
Red 100
Orange 1,000
Yellow 10,000
Green 100,000
Blue 1,000,000
Silver 0.01
Gold 0.1
Resistance
Tolerance
Color Tolerance
Silver ±10%
Gold ±5%
Brown ±1%
Red ±2%
Orange ±3%
Green ±0.5%
Blue ±0.25%
Violet ±0.1%
1
2 Multiplier Tolerance
Multiplier
For the No. 0 1 2 3 4 5 8 9
Multiply By 1 10 100 1k 10k 100k .01 0.1
(+)
(–)
(+)
(–)
Axial
Radial
-4-
CONSTRUCTION
Solder
Soldering Iron
Foil
Solder
Soldering Iron
Foil
Component Lead
Soldering Iron
Circuit Board
Foil
Rosin
Soldering iron positioned
incorrectly.
Solder
Gap
Component Lead
Solder
Soldering Iron
Drag
Foil
1. Solder all components from the
copper foil side only. Push the
soldering iron tip against both the
lead and the circuit board foil.
2. Apply a small amount of solder to
the iron tip. This allows the heat to
leave the iron and onto the foil.
Immediately apply solder to the
opposite side of the connection,
away from the iron. Allow the
heated component and the circuit
foil to melt the solder.
1. Insufficient heat - the solder will
not flow onto the lead as shown.
3. Allow the solder to flow around
the connection. Then, remove
the solder and the iron and let the
connection cool. The solder
should have flowed smoothly and
not lump around the wire lead.
4.
Here is what a good solder
connection looks like.
2. Insufficient solder - let the
solder flow over the connection
until it is covered.
Use just enough solder to cover
the connection.
3. Excessive solder - could make
connections that you did not
intend to between adjacent foil
areas or terminals.
4. Solder bridges - occur when
solder runs between circuit paths
and creates a short circuit. This is
usually caused by using too much
solder.
To correct this, simply drag your
soldering iron across the solder
bridge as shown.
What Good Soldering Looks Like
A good solder connection should be bright, shiny, smooth, and uniformly
flowed over all surfaces.
Types of Poor Soldering Connections
Introduction
The most important factor in assembling your XP-720K Power Supply
Kit is good soldering techniques. Using the proper soldering iron is of
prime importance. A small pencil type soldering iron of 25 - 40 watts is
recommended. The tip of the iron must be kept clean at all times and
well tinned.
Solder
For many years leaded solder was the most common type of solder
used by the electronics industry, but it is now being replaced by leadfree solder for health reasons. This kit contains lead-free solder, which
contains 99.3% tin, 0.7% copper, and has a rosin-flux core.
Lead-free solder is different from lead solder: It has a higher melting
point than lead solder, so you need higher temperature for the solder to
flow properly. Recommended tip temperature is approximately 700
O
F;
higher temperatures improve solder flow but accelerate tip decay. An
increase in soldering time may be required to achieve good results.
Soldering iron tips wear out faster since lead-free solders are more
corrosive and the higher soldering temperatures accelerate corrosion,
so proper tip care is important. The solder joint finish will look slightly
duller with lead-free solders.
Use these procedures to increase the life of your soldering iron tip when
using lead-free solder:
• Keep the iron tinned at all times.
• Use the correct tip size for best heat transfer. The conical tip is the
most commonly used.
• Turn off iron when not in use or reduce temperature setting when
using a soldering station.
•
Tips should be cleaned frequently to remove oxidation before it becomes
impossible to remove. Use Dry Tip Cleaner (Elenco
®
#SH-1025) or Tip
Cleaner (Elenco®#TTC1). If you use a sponge to clean your tip, then use
distilled water (tap water has impurities that accelerate corrosion).
Safety Procedures
• Always wear safety glasses or safety goggles to
protect your eyes when working with tools or
soldering iron, and during all phases of testing.
• Be sure there is adequate ventilation when soldering.
•
Locate soldering iron in an area where you do not have to go around
it or reach over it. Keep it in a safe area away from the reach of
children.
• Do not hold solder in your mouth. Solder is a toxic substance.
Wash hands thoroughly after handling solder.
Assemble Components
In all of the following assembly steps, the components must be installed
on the top side of the PC board unless otherwise indicated. The top
legend shows where each component goes. The leads pass through the
corresponding holes in the board and are soldered on the foil side.
Use only rosin core solder.
DO NOT USE ACID CORE SOLDER!
'
-5-
ASSEMBLE COMPONENTS TO PC BOARD
Figure A
Diodes have polarity. Be sure
that the band is in the correct
direction.
Figure B
Electrolytics have a
polarity marking
indicating the (–)
lead. The PC board
is marked to show
the lead position.
Warning: If the capacitor is connected with
incorrect polarity it may heat up and either leak
or cause the capacitor to explode.
Figure C
Mount the transistor with the
flat side as shown on the top
legend. Leave 1/4” between
the part and PC board.
Band
D5 - 1N5400 Diode
D6 - 1N5400 Diode
D7 - 1N5400 Diode
D8 - 1N5400 Diode
(see Figure A)
C1 - 10μF Electrolytic
C2 - 10μF Electrolytic
C3 - 10μF Electrolytic
C4 - 10μF Electrolytic
C8 - 10μF Electrolytic
(see Figure B)
C7 - 4700μF Electrolytic
(see Figure B)
Q1 - A70 Transistor
(see Figure C)
D4 - 1N4001 Diode
D3 - 1N4001 Diode
D2 - 1N4001 Diode
D1 - 1N4001 Diode
(see Figure A)
R2 - 150Ω Resistor
R1 - 150Ω Resistor
(brn-green-brn-gold)
C6 - 2200μF Electrolytic
C5 - 2200μF
Electrolytic
(see Figure B)
R3 - 2.7Ω Resistor
R4 - 2.7Ω Resistor
(red-violet-gold-gold)
R5 - .18Ω Resistor
Flat
1/4”
(–) (+)
Polarity
Mark
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