Elenco Electronics LP-425K Assembly And Instruction Manual

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Elenco Electronics LP-425K Assembly And Instruction Manual | Manualzz

LOGIC PULSER KIT

MODEL LP-425K

Assembly and Instruction Manual

Elenco Electronics, Inc.

Copyright © 1995 Elenco Electronics, Inc.

REV-D Revised 2002 753262

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.

Qty.

Symbol

2 R1, R16

1 R17

2 R11, R13

3 R12, R14, R15

1 R8

4 R2, R7, R9, R10

1 R5

2 R3, R6

1 R4

RESISTORS

Description

100

W

5% 1/4W

470

W

5% 1/4W

2k

W

5% 1/4W

20k

W

5% 1/4W

68k

W

5% 1/4W

100k

W

5% 1/4W

1M

W

5% 1/4W

1.8M

W

5% 1/4W

10M

W

5% 1/4W

Color Code brown-black-brown-gold yellow-violet-brown-gold red-black-red-gold red-black-orange-gold blue-gray-orange-gold brown-black-yellow-gold brown-black-green-gold brown-gray-green-gold brown-black-blue-gold

Qty.

Symbol Description

2 C6, C7 100pF (101) Discap

1 C4 .001

m

F (102) Mylar

1

1

C3

C1

.01

m

F (103) Mylar

.1

m

F (104) Discap

CAPACITORS

Part #

221017

231017

241017

251010

Qty.

Symbol Description

1 C5 1 m

F Tantalum

1

1

C8

C2

10 m

F Lytic 35V

22 m

F Lytic 25V

Qty.

Symbol Description

3 D1,D4,D5 Diode 1N4001

1 D3

1 D2

Diode 1N4148

Diode Zener 1N5246

3 Q1,Q4,Q5 Transistor 2N3904

Qty.

Description

1 PC Board

1 Switch SPDT

1 Pulser Tip

1 Case

2 Screw #4 x 5/8”

1 IC Socket 14-pin

3 Pins

1 Alligator Clip Black

SEMICONDUCTORS

Part #

314001

314148

315246

323904

Qty.

Symbol Description

2 Q2, Q3 2N3906 Transistor

1 U1 IC 4069 or 74C04

1 D6 LED

MISCELLANEOUS

Part #

517009

541024

616001

623005

643450

664014

665001

680001

Qty.

Description

1 Alligator Clip Red

1 Label Front

1 Label Back

1 Wire 22 Gauge Red 1.5”

3’ Wire 2 Conductor

1” Tubing #20

1” Shrink Tubing (red)

1 Solder Tube

Part #

260010

271016

272245

Part #

323906

334069

or 34C004

350001

Part #

680002

724005

724006

814220

870500

890020

890312

9ST4

Part #

131000

134700

142000

152000

156800

161000

171000

171800

181000

SPECIFICATIONS

Maximum Allowable Supply Voltage

Maximum Allowable Voltage on Output

Maximum Sync. Input Voltage

Operating Supply Voltage Range

Free Air Operating Temperature Range

Output Pulse Width at 100mA Load

Output Current

1) Pulser Mode

2) Square Wave Output

Pulse Repetition Rate

Sync. Input Impedance

+20V, +25V/15 sec.

+35V

+120V/15 sec.

4 - 15VDC

0 - 50 O

10 m

S

C

100mA Sink/Source

5mA Sink/Source

.5PPS / 400PPS

1M

W

-1-

IDENTIFYING RESISTOR VALUES

Use the following information as a guide in properly identifying the value of resistors.

Bands

1 2 Multiplier

Tolerance

BAND 1

1st Digit

Color

Black

Brown

Red

Orange

Yellow

Green

Blue

Violet

Gray

White

Digit

0

1

2

3

4

5

8

9

6

7

BAND 2

2nd Digit

Color

Black

Brown

Red

Orange

Yellow

Green

Blue

Violet

Gray

White

Digit

0

1

2

3

4

5

8

9

6

7

Multiplier

Color

Black

Brown

Red

Orange

Yellow

Green

Blue

Silver

Gold

Multiplier

1

10

100

1,000

10,000

100,000

1,000,000

0.01

0.1

Resistance

Tolerance

Color

Silver

Gold

Brown

Red

Orange

Green

Blue

Violet

Tolerance

+10%

+5%

+1%

+2%

+3%

+.5%

+.25%

+.1%

IDENTIFYING CAPACITOR VALUES

Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads), or m

F (microfarads).

Most capacitors will have their actual value printed on

Second Digit

First Digit

103K

100V

Multiplier

Tolerance *

Multiplier

Maximum Working Voltage

The value is 10 x 1,000 = 10,000pF or .01

m

F 100V them. Some capacitors may have their value printed in the following manner. The maximum operating voltage may also be printed on the capacitor.

For the No.

0

Multiply By 1

1

10

2

100

3

1k

4 5

10k 100k

8

.01

9

0.1

Note: The letter “R” may be used at times to signify a decimal point; as in 3R3 = 3.3

* The letter M indicates a tolerance of +20%

The letter K indicates a tolerance of +10%

The letter J indicates a tolerance of +5%

INTRODUCTION

Assembly of your LP-425 Logic Pulser will prove to be an exciting project and give much satisfaction and personal achievement. If you have experience in soldering and wiring technique, you should have no problems. For the beginner, care must be given in identifying the proper components and in good soldering habits.

Above all, take your time and follow the easy step-by-step instructions.

Remember, “an ounce of prevention is worth a pound of cure”.

Avoid making mistakes and no problems will occur.

CIRCUIT DESCRIPTION

The Elenco Model LP-425 Logic Pulser is a very handy device for inspecting and repairing logic circuits. By injecting a signal directly to the circuit, you can avoid removing the ICs or other circuit components. The Logic Pulser will thus help you to troubleshoot wiring errors and malfunctioning components.

The Logic Pulser operates by producing a large transient current for a short period of time. This will not harm the components under test since the average current is very small. The injected voltage is produced by the transient current flowing through the inherent resistance of the circuit.

-2-

The LP-425 Logic Pulser can produce a 10 microsecond pulse at 100mA load.

The signal frequency can be set to .5Hz or 400Hz by the pulse repetition rate switch on the front of the Logic

Pulser. This feature makes the Logic Pulser a very effective tool. The Logic Pulser also has a square wave output terminal (SQ).

When the pulse repetition rate switch is set to 400Hz, the signal on the square wave terminal is a square wave. When the switch is set to .5Hz, the signal on the terminal is a pulse, high for 90% of the time and ground for the remaining 10%. The sync input terminal (SYNC)

Logic Pulser can be used to produce an externally synchonized signal at the output.

CONSTRUCTION

Introduction

The most important factor in assembling your LP-425K Logic Pulser 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.

Safety Procedures

• Wear eye protection when soldering.

• Locate soldering iron in an area where you do not have to go around it or reach over it.

Do not hold solder in your mouth. Solder contains lead and is a toxic substance. Wash your hands thoroughly after handling solder.

• Be sure that there is adequate ventilation present.

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.

Foil Side

Use only rosin core solder of 63/37 alloy.

DO NOT USE ACID CORE SOLDER!

Mount Part Bend Leads to

Hold Part

Solder and

Cut Off Leads

Types of Poor Soldering Connections What Good Soldering Looks Like

A good solder connection should be bright, shiny, smooth, and uniformly flowed over all surfaces.

1.

Solder all components from the copper foil side only.

Push the soldering iron tip against both the lead and the circuit board foil.

Soldering Iron

Component Lead

Foil

1.

Insufficient heat - the solder will not flow onto the lead as shown.

Rosin

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.

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.

Solder

Foil

Solder

Foil

4.

Here is what a good solder connection looks like.

Circuit Board

Soldering Iron

Soldering Iron

Soldering iron positioned incorrectly.

2.

Insufficient solder - let the solder flow over the connection until it is covered.

Use just enough solder to cover the connection.

Solder

Component Lead

Gap

3.

Excessive solder - could make connections that you did not intend to between adjacent foil areas or terminals.

Solder

-3-

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.

Foil

Soldering Iron

Drag

ASSEMBLE COMPONENTS TO THE PC BOARD

Refer to the top legend on the PC board, install and solder the following resistors. All are 1/4 watt, 5% tolerance.

(Resistors R11 and R12 install vertical).

R11 - 2k

W

Resistor

(red-black-red-gold)

(see Figure 1)

R14 - 20k

W

Resistor

(red-black-orange-gold)

R9 - 100k

W

Resistor

(brown-black-yellow-gold)

R7 - 100k

W

Resistor

(brown-black-yellow-gold)

R10 - 100k

W

Resistor

(brown-black-yellow-gold)

R6 - 1.8M

W

Resistor

(brown-gray-green-gold)

R13 - 2k

W

Resistor

(red-black-red-gold)

R3 - 1.8M

W

Resistor

(brown-gray-green-gold)

R12 - 20k

W

Resistor

(red-black-orange-gold)

(see Figure 1)

R15 - 20k

W

Resistor

(red-black-orange-gold)

R17 - 470

W

Resistor

(yellow-violet-brown-gold)

R8 - 68k

W

Resistor

(blue-gray-orange-gold)

R4 - 10M

W

Resistor

(brown-black-blue-gold)

R2 - 100k

W

Resistor

(brown-black-yellow-gold)

R5 - 1M

W

Resistor

(brown-black-green-gold)

R16 - 100

W

Resistor

(brown-black-brown-gold)

R1 - 100

W

Resistor

(brown-black-brown-gold)

Figure 1

Stand resistor on end.

-4-

ASSEMBLE COMPONENTS TO THE PC BOARD

Refer to the top legend on the PC board, install and solder the following diodes and capacitors.

D5 - 1N4001 Diode

(see Figure 2)

C8 - 10 m

F Lytic Capacitor

(see Figure 3A)

C6 - 100pF Discap

(may be marked 101)

C7 - 100pF Discap

(may be marked 101)

D3 - 1N4148 Diode

(see Figure 2)

C5 - 1 m

F Tantalum

(May marked 105)

(see Figure 3B)

C3 - .01

m

F Mylar Capacitor

(May be marked 103)

C4 - .001

m

F Mylar Capacitor

(May be marked 102)

D4 - 1N4001 Diode

(see Figure 2)

D2 - 1N5246 Zener Diode

(see Figure 2)

C2 - 22 m

F Lytic Capacitor

(see Figure 3A)

D1 - 1N4001 Diode

(see Figure 2)

C1 - .1

m

F Discap

(may be marked 104)

Figure 2

When mounting diodes horizontally, mount as indicated by the band

(diodes have polarity).

Band

Figure 3A

Polarity Mark

(–) (+)

Figure 3B

(–) (+)

Some capacitors have polarity markings indicating the positive (+) or negative

(–) lead. The PC board is marked to show the lead positions.

-5-

ASSEMBLE COMPONENTS TO THE PC BOARD

Refer to the top legend on the PC board, install and solder the following components.

Q3 - 2N3906 Transistor

(see Figure 7)

Q4 - 2N3904 Transistor

(see Figure 7)

Q5 - 2N3904 Transistor

(see Figure 7)

Q2 - 2N3906 Transistor

(see Figure 7)

Figure 4

D6 - LED

(see Figure 8)

Q1 - 2N3904 Transistor

(see Figure 7)

U1 - 14-Pin IC Socket

U1 - 74C04 IC or 4069

(see Figure 5)

SW1 - Switch

(see Figure 6)

P1, P2, P3 - Pins

Do not install the pins to the

PC board.

They will be installed later. Tin (that is, put a small amount of solder on) the foil around the holes for the three pins.

Do not block

the hole. Tin the bottom fo the pin as shown in Figure 4.

Tin Here

Figure 5

Install and solder the IC socket. Insert the IC into the socket with the notch in the direction shown on the top legend.

Figure 7

Mount the transistor with the flat side in the direction shown on the top legend. Leave 1/4” between the part and PC board.

Notch

Figure 6

Insert the tabs and terminals into the PC board.

Solder terminals only.

1/4”

Figure 8

Cut a 3/8” piece of tubing for each LED lead, to be used as stand-offs.

Mount the LED with the flat side in the direction shown on the top legend.

Flat

Tubing

3/8”

Tab

Tab

-6-

Install the power cord as shown in Figure 9. Pull the power cord wires apart about 2 inches on one end. Strip the insulation off of both wires to expose 1/4” of bare wire. Note that one wire is ribbed on the edge. Solder the red alligator clip to the ribbed wire. Solder the black clip to the smooth wire. On the other side of the power cord, pull the wires apart 1/2”.

Strip 1/4” of insulation off of both wires. Make a knot to serve as a strain relief (about 1 inch from the end).

Solder the ribbed wire to the hole marked “+” and the smooth wire to the hole marked “–”.

Install the pulser tip as shown in Figure 10.

Using the 1 1/2” wire, strip 1/4” of insulation off of both ends. Solder one end to point P on the PC board. Solder the other end of the wire to the pulser tip groove.

Punch out the five holes in the front label. Peel the backing off the front and back labels and stick them to the case as shown in Figure 11.

The front label should be placed toward the back of the indent (toward the 3 pins) so that the LED and switch holes align with the case holes.

Insert the 3 pins P1, P2, and P3 into their holes in the front label. Insert the PC board into the case so that the LED and switch protrude through the label (see Figure 11). Insert the 3 pins into the

PC board and solder (see Figure 4).

Place the unit into the case bottom and fasten with two #4 screws. Do not over-tighten or the holes may strip out.

Cut a 13/16” piece of red shrink tubing and slide it over the pulser tip until it touches the plastic case. Shrink the tubing by heating it with your soldering iron. Be sure the soldering iron does not contact the tubing or plastic case.

This completes the assembly procedure. Your Logic

Probe is now ready for testing.

Solder the wire to the clip, then bend the tabs over the insulated wire.

Clip

Smooth Wire

Ribbed Wire

Figure 9

Front Label

Case (top)

Place knot in case

Assembled

PC Board

Red Shrink

Tubing

Figure 10

Back Label

#4 x 5/8” Screws

-7-

Case (bottom)

Figure 11

TESTING YOUR LOGIC PULSER

Checking out your Logic Pulser for proper operation is fairly easy. All that is needed is a 9V battery or other DC power source (5-10V). Connect the red alligator clip to the positive terminal of the battery and the black clip to the negative terminal.

Set the pulse repetition rate switch to the 0.5PPS

position. Check the red LED. It should blink once every 2 seconds (0.5PPS).

Set the switch to

400PPS. The Logic Pulser generates a frequency of 400Hz. At this frequency, the LED flashes at a rate that makes it appear to be on continuously. If either of these tests fail: a) Check the input cable. The ribbed wire with the red alligator clip should go to the hole marked

(+).

b) Check for cold solder joints and solder bridges around the IC. Check that the IC notch matches the notch shown on the PC board.

c) Check the soldering and polarity of diodes D1,

D2, D3 and D6 (LED).

d) Check that transistor Q5 is the correct type and is mounted with the flat side as shown on the PC board.

e) Check the soldering and the values of capacitors

C1 through C5.

f) Check the soldering and the values of resistors

R1 through R5 and R15 through R17.

If you have an oscilloscope, connect it to the Square

(SQ) Pin and observe the waveforms shown in

Figure 12 for pulse repetition rate switch settings of

400PPS and .5PPS.

The times shown are approximate. If you do not get these waveforms: a) Check the value and soldering of R16.

b) Check that transistor Q5 is the correct type and is mounted with the flat as shown on the PC board.

c) Check the value and soldering of capacitors C3,

C4 and C5.

Connect the pulser tip to the resistor combinations shown in Figure 12 and observe the waveforms shown for the pulser tip. If you do not get these waveforms: a) Check that transistors Q1 through Q4 are the correct type and are mounted with the flat side as shown on the PC board.

b) Check the soldering and polarity of diodes D4 and D5.

c) Check the soldering and values of resistors R7 through R14.

d) Check the soldering and values of capacitors C3 through C8.

Figure 12

-8-

SCHEMATIC DIAGRAM

-9-

QUIZ

1) The LP-425 Logic Pulser can produce a _______ microsecond pulse at 100mA.

A. 30

B. 15

C. 10

D. 20

2) The Logic Pulser operates by producing a large transient current for a __________ period of time.

A. long

B. short

C. long and short

D. none of the above.

3) The signal frequency of the Logic Pulser are _____ Hz and _____ Hz.

A. 10, 100

B. 0.1, 300

C. 0.5, 400

D. none of the above.

4) The Logic Pulser also has a ___________ wave output terminal.

A. square

B. sine

C. saw

D. cosine

5) In operating supply voltage range is ____________.

A. 0V to 10VDC.

B. 4V to 15VDC.

C. 20V to 45VDC.

D. 0.1V to 5VDC.

6) The LP-425 Logic Pulser is a very handy device for inspecting and repairing __________________.

A. motor circuits.

B. logic circuits.

C. lighting circuits.

D. radar circuits.

7) The Sync input impedance of the LP-425 is

___________.

A. 3M

W

.

B. 2M

W

.

C. 4M

W

.

D. 1M

W

.

8) When the switch is set to 0.5Hz, the signal on the terminal is a pulse, high for ________ of the time and ground for the remaining _________.

A. 50%, 50%.

B. 20%, 80%.

C. 90%, 10%.

D. 60%, 40%.

9) The Sync Input Terminal (SYNC) Logic Pulser can be used to produce an externally synchronized signal at the ____________.

A. output.

B. input.

C. input and output.

D. none of the above.

10) The Free air operating temperature range is ______.

A. 0 - 100 O C.

B. 30 - 40 O C.

C. 0 - 50 O C.

D. 25 - 75 O C.

Other Logic Probe Kits Available

Logic Probe Model LP-525K (kit) Logic Probe Model LP-535K (kit)

Digital Logic Probe in kit form provides convenient and precise use in measurement of logic circuits. It displays logic levels (high or low), pulses and voltage transients down to 30 nanoseconds and a maximum input of 20MHz.

Large PC board and detailed manual for fast construction.

Advanced design with audible sound for signal detection in logic circuits. It displays logic levels (high or low) pulses and voltage transients down to 10 nanoseconds.

High intensity LED readouts provide instant response to the logic state.

Simplified circuitry for fast construction.

Detailed instructions, illustrations and testing included.

10.C

9.A; 8.C; 7.D; 6.B; 2.B; 1.C; s to Quiz: Answer 5.B; 4.A;

-10-

3.C;

Elenco Electronics, Inc.

150 W. Carpenter Avenue

Wheeling, IL 60090

(847) 541-3800 http://www.elenco.com

e-mail: [email protected]

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