Elenco Electronics M-2666K Assembly And Instruction Manual

DIGITAL MULTIMETER KIT

MODEL M-2666K

WIDE RANGE DIGITAL MULTIMETER WITH

CAPACITANCE AND TRANSISTOR TESTING FEATURES

Assembly and Instruction Manual

Elenco

TM

Electronics, Inc.

Copyright © 2003 by Elenco

TM

Electronics, Inc. All rights reserved.

No part of this book shall be reproduced by any means; electronic, photocopying, or otherwise without written permission from the publisher.

753128

INTRODUCTION

Assembly of your M-2666 Digital Multimeter Kit 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 to 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”.

The meter kit has been divided into a number of sections to make the assembly easy and avoid major problems with the meter operation.

Section A - Meter display circuit assembly.

Section B - DC voltage and current circuit assembly.

Section C - AC voltage and current circuit assembly.

Section D - Resistance & buzzer circuit assembly.

Section E - Capacitance and transistor testing circuit assembly.

Section F - Final assembly.

THEORY OF OPERATION

A block diagram of the M-2666K is shown in Figure 1.

Operation centers around a custom LSI chip. This IC contains a dual slope A/D converter, display, latches, decoder and the display driver. A block diagram of the IC functions is shown in Figure 6. The input voltage, current or ohm signals are conditioned by the function and selector switches to produce and output

DC voltage between 0 and +199mV.

If the input signal is 100VDC, it is reduced to 100mV DC by selecting a 1000:1 divider.

Should the input be

100VAC, then after the divider it is processed by the

AC converter to produce 100mVDC. If current is to be read, it is converted to a DC voltage via internal shunt resistors. For resistance measurements, an internal voltage source supplies the necessary 0-199mV voltage to be fed to the IC input.

V/

Ω

COMM

Range

Switches

V

Voltage

Divider

V

Ω

Ohms

Converter

Ω

AC

Converter

VAC

VAC/mA AC mA

Function

Switches

DC

Analog

Data

A/D

Converter and

Display

Driver mA mA

Current

Shunts

Decimal

Point

Display

Figure 1 Simplified Block Diagram

The input of the 7106 IC is fed to an A/D (analog to digital) converter. Here the DC voltage amplitude is changed into a digital format. The resulting signals are processed in the decoders to light the appropriate

LCD segment.

Timing for the overall operation of the A/D converter is derived from an external oscillator whose frequency is selected to be 40kHz. In the IC, this

-1-

frequency is divided by four before it clocks the decade counters.

It is further divided to form the three convert-cycle phases.

The final readout is clocked at about three readings per second.

Digitized measurements data is presented to the display as four decoded digits (seven segments) plus polarity.

Decimal point position on the display is determined by the selector switch setting.

A/D CONVERTER

A simplified circuit diagram of the analog portion of the A/D converter is shown in Figure 2. Each of the switches shown represent analog gates which are operated by the digital section of the A/D converter.

Basic timing for switch operation is keyed by an external oscillator.

The conversion process is continuously repeated. A complete cycle is shown in Figure 2.

Any given measurement cycle performed by the A/D

BUFFER

AMP

EXTERNAL

INPUTS

+REF

(FLYING

CAPACITOR)

READ

INTEG

UNKNOWN

INPUT

VOLTAGE+

AZ converter can be divided into three consecutive time periods: autozero (AZ), integrate (INTEG) and read.

Both autozero and integrate are fixed time periods.

A counter determines the length of both time periods by providing an overflow at the end of every

1,000 clock pulses. The read period is a variable time, which is proportional to the unknown input voltage. The value of the voltage is determined by counting the number of clock pulses that occur during the read period.

AZ

INTEGRATOR

COMPARATOR

AZ

TO

DIGITAL

CONTROL

LOGIC

INTEG.

INTEG READ

AZ

+.20

.15

.10

.05

0

COUNTER OUTPUT

0

166.7mS

10,000

0

500 1000 1500 2000

Figure 2 Dual Slope A/D Converter

AZ

During autozero, a ground reference is applied as an input to the A/D converter. Under ideal conditions the output of the comparator would also go to zero.

However, input-offset-voltage errors accumulate in the amplifier loop, and appear at the comparator output as an error voltage. This error is impressed across the AZ capacitor where it is stored for the remainder of the measurement cycle. The stored level is used to provide offset voltage correction during the integrate and read periods.

The integrate period begins at the end of the autozero period. As the period begins, the AZ switch opens and the INTEG switch closes. This applies the unknown input voltage to the input of the A/D converter. The voltage is buffered and passed on to the input of the

A/D converter. The voltage is buffered and passed on to the integrator to determine the charge rate (slope) on the INTEG capacitor. At the end of the fixed integrate period, the capacitor is charged to a level proportional to the unknown input voltage. This voltage is translated to a digital indication by discharging the capacitor at a fixed rate during the read period, and counting the number of clock pulses that occur before it returns to the original autozero level.

As the read period begins, the INTEG switch opens and the read switch closes. This applies a known reference voltage to the input of the A/D converter. The polarity of this voltage is automatically selected to be opposite that of unknown input voltage, thus causing the INTEG capacitor to discharge as fixed rate (slope). When the charge is equal to the initial starting point (autozero level), the read period is ended. Since the discharge slope is fixed during the read period, the time required is proportional to the unknown input voltage.

The autozero period and thus a new measurement cycle begins at the end of the read period. At the same time, the counter is released for operation by transferring its contents (previous measurement value) to a series of latches. This stored stat is then decoded and buffered before being used for driving the LCD display.

-2-

VOLTAGE MEASUREMENT

Figure 3 shows a simplified diagram of the voltage measurement function.

The input divider resistors add up 10M

Ω with each step being a division of 10.

The divider output should be within –0.199 to +0.199V or the overload indicator will function. If the AC function is selected, the divider output is AC coupled to a full wave rectifier and the DC output is calibrated to equal the rms level of the AC input.

Volts

9M

Ω

900k

Ω

20V

90k

Ω

2V

200V

200mV

9k

Ω

750V

Common

9

Ω

DC

AC

AC to DC

Converter

Low Pass

Filter

100mV

Ref

7106

Figure 3 Simplified Voltage Measurement Diagram

CURRENT MEASUREMENT

Figure 4 shows a simplified diagram of the current measurement positions.

Internal shunt resistors convert the current to between –0.199 to +0.199V which is then processed in the 7106 IC to light the appropriate

LCD segments. If the current is AC in nature, the

AC converter changes it to the equivalent DC value.

A

20A

200

µ

A

20A

900

Ω

2mA

20mA

90

Ω

9

Ω

200mA

0.99

Ω

0.01

Ω

COM

DC

AC

AC - DC

Converter

Low Pass

Filter

100mV

Ref

7106

Figure 4 Simplified Current Measurement Diagram

-3-

RESISTANCE MEASUREMENTS

Figure 5 shows a simplified diagram of the resistance measurement function.

External

Resistor

100

Ω

900

Ω

9k

Ω

20k

Ω

90k

Ω

200k

Ω

900k

Ω

2M

Ω

9M

Ω

20M

Ω

2k

Ω

200

Ω

Voltage

Source

Low Pass

Filter

100mV

Ref

7106

Figure 5 Simplified Resistance Measurement Diagram

A simple series circuit is formed by the voltage source, a reference resistor from the voltage divider

(selected by range switches), and the external unknown resistor. The ratio of the two resistors is equal to the ratio of their respective voltage drops.

Therefore, since the value of one resistor is known, the value of the second can be determined by using the voltage drop across the known resistor as a reference. This determination is made directly by the A/D converter.

Overall operation of the A/D converter during a resistance measurement is basically as described earlier in this section, with one exception.

The reference voltage present during a voltage measurement is replaced by the voltage drop across the reference resistor.

This allows the voltage across the unknown resistor to be read during the read period. As before, the length of the read period is a direct indication of the value of the unknown.

h

FE

MEASUREMENT

Figure 6 shows a simplified diagram of the h

FE measurement function. Internal circuits in the 7106

IC maintain the COMMON line at 2.8 volts below

V+.

When a PNP transistor is plugged into the transistor socket, base to emitter current flows through resistor R49. The voltage drop in resistor

R49 due to the collector current is fed to the 7106 and indicates the h

FE of the transistor. For an NPN transistor, the emitter current through R50 indicates the h

FE of the transistor.

220k

Ω

COM

V+

PNP NPN

E C

B

C

10

Ω

B

E

R50

220k

Ω

Figure 6

Low Pass

Filter

100mV

Ref

7106

CAPACITANCE MEASUREMENT

The capacitor circuit consists of four opamps. IC3 D& A form an oscillator, which is applied to the test-capacitor through the test leads. The capacitor couples the oscillator to pin 6 of IC3B. The amount of voltage developed at pin 6 is indicative of the capacitors ESR value. IC3B and C amplify the signal which is seen at pin 8. The AC signal is then converted to a DC voltage and displayed on the meter.

Figure 7

-4-

a b e f d g a b c e f d g a b c e f d g a b c

28

BACKPLANE

TYPICAL SEGMENT OUTPUT

V+

0.5mA

Segment

Output

2mA

Internal Digital Ground

* Three inverters.

One inverter shown for clarity.

LCD PHASE DRIVER

7 Segment

Decode

7 Segment

Decode

7 Segment

Decode

LATCH

Thousand Hundreds Tens Units

200

*

To Switch Drivers

From Comparator Output

CLOCK

OSC 1

7

OSC 2

6

OSC 3

4

-4

LOGIC CONTROL

Internal Digital Ground

1V

V+

6.2V

500

Ω

3

TEST

34

V

DIGITAL SECTION

39

IN HI

C

V+

REF

+

10

µ

A

INT

REF HI

42 44

A-Z &

Z1

C

REF

REF LO C

REF

43

41

BUFFER

36

R

INT

V+

8

A-Z &

Z1

+

2.8V

Z1

DE (-) DE (+)

6.2V

37

C

AZ

AUTO

ZERO

INTEGRATOR

C

INT

35

INT

+

A-Z

+

COMPARATOR

A-Z

+

DE (+)

DE (-)

ZERO

CROSSING

DETECTOR

POLARITY

FLIP/FLOP

TO

DIGITAL

SECTION

ANALOG SECTION of 7106

40

COMMON

IN LO

38

INT

A-Z & DE(+)

& Z1

V

34

Figure 8 7106 Functions

-5-

ASSEMBLY

The meter kit has been divided into a number of sections to make the assembly easy and avoid major problems with the meter operation.

ONLY OPEN COMPONENT BAGS THAT ARE

CALLED FOR IN YOUR ASSEMBLY PROCEDURE.

DO NOT OPEN ANY OTHER BAGS.

Do not build more than one section of your meter at a time. Your instructor must approve the proper operation of the section you have built before you proceed to the next section. This procedure will minimize the problems you may have at the completion of the project.

Your kit program is divided into Sections “A – F”.

The small parts bags will be marked accordingly.

The sections are listed below.

Section A - Meter Display Circuit Assembly.

Section B - DC Voltage and Current Circuit

Assembly.

Section C - AC Voltage and Current Circuit

Assembly.

Section D - Resistance & Buzzer Circuit Assembly.

Section E - Capacitance and Transistor Circuit

Assembly.

Section F - Final Assembly.

IMPORTANT CONSTRUCTION NOTES

1. Wash your hands with soap and water before you assemble this kit. The high impedance areas on the circuit board can be contaminated by salt and oil from your skin. If these areas become contaminated, your completed multimeter may not meet the listed specifications.

Handle the circuit board only by its edges.

2. Avoid any excessive accumulation of resin buildup whenever you solder a connection.

3. Take your time assembling the circuit board.

Work at a slow pace. Remember that accuracy is far more important than speed.

4. When you perform the steps in assembly, identify each respective component before you install it.

Then position it over its outline on the top legend side of the PC board, unless otherwise indicated.

5. Check for the proper polarity of ICs, diodes, electrolytic capacitors, battery snap and LCD.

-6-

CONSTRUCTION

Introduction

The most important factor in assembling your M-2666 Digital Multimeter 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.

Use only rosin core solder of 63/37 alloy.

DO NOT USE ACID CORE SOLDER!

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

Types of Poor Soldering Connections

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

-7-

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

IDENTIFYING CAPACITOR VALUES

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

µ

F (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 Multiplier

Multiplier

For the No.

0

Multiply By 1

1

10

2

100

3

1k

4 5 8

10k 100k .01

9

0.1

First Digit

103K

100V

Tolerance*

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

Maximum Working Voltage

The value is 10 x 1,000 =

10,000pF or .01

µ

F 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%

IDENTIFYING RESISTOR VALUES

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

4 Bands

1 2

Multiplier

Tolerance

5 Bands

1 2 3 Multiplier

Tolerance

PART IDENTIFICATION CARDS

M-2666K

SECTION A

To help identify the resistors and diodes used in the construction of your digital multimeter we have mounted the diodes and resistors of each section onto a card.

The card will help you find the diodes and resistors quickly. THE PARTS WILL NOT

NECESSARILY BE LISTED IN THE ORDER SHOWN IN THE PARTS LIST

SECTION OR IN THE ASSEMBLY PROCEDURE.

EXAMPLE

When you are ready to assemble the meter kit, follow the procedure shown. For an example refer to page 11 for assembly of Section “A”. The first resistor called for is R-2, 470k

Ω resistor (yellow-violet-yellow-gold). Locate it on the card ( ), verify that it is the correct value. Some resistors may be mounted backwards on the card so you must be certain that you are reading the resistors correctly. When the correct value has been established, only then will you mount it into its correct position on the PC board.

-8-

RESISTOR READING EXERCISE

Before starting assembly of your digital multimeter project, you should be thoroughly familiar with the 5 band color code system.

Many of the resistor values will be identified by color bands and it is easy to mistake their value if you read the colors

(1) yellow-black-black-black-brown incorrectly or read the value from the wrong end.

Do the following exercise in resistor values. Place your answer in the box beneath the resistor.

Answers are on the bottom of this page.

(2) white-black-black-red-green

(3) brown-red-violet-red-brown

(5) brown-black-black-black-brown

(7) white-black-black-yellow-green

(9) brown-black-black-orange-green

(4) green-black-green-brown-green

(6) brown-green-gray-orange-brown

(8) white-black-black-silver-green

(10) orange-white-red-red-brown

(11) gray-white-black-black-brown (12) brown-brown-black-red-brown

Ω

+1%; 5) 100

Ω

+1%;

Ω

+.5%;

12) 11k

4) 5.05k

Ω

+1%;

Ω

+1%;

11) 890

3) 12.7k

Ω

+1%;

Ω

+.5%; 2) 90k

10) 39.2k

-9-

Ω

+1%;

Ω

+.5%;

1) 400

9) 100k

cise:

Ω

+.5%; 8) 9

Ω

+.5%; 7) 9M

s to Resistor Reading Exer

Ω

+1%; 6) 158k

Answer

SECTION A

Meter Display Circuit

PARTS LIST - SECTION A

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 TM 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.

Qty.

Symbol

2 R4, R5

1 R3

1 R1

3 R7, R8, R9

2 R2, R6

Qty.

Symbol

1 C5

1 C1

3 C2, C3, C4

1 C6

Qty.

Symbol

1 T1

Qty.

Description

1 LCD

1 Zebra

1 PC Board M2666K

1 Switch On/Off (SW1)

1 Battery 9V

RESISTORS

Description

100k

Ω

5% 1/4W

200k

Ω

5% 1/4W

220k

Ω

5% 1/4W

470k

Ω

5% 1/4W

1M

Ω

5% 1/4W

Color Code

brown-black-yellow-gold red-black-yellow-gold red-red-yellow-gold yellow-violet-yellow-gold brown-black-green-gold

Value

100pF (101)

.1

µ

F (104)

.1

µ

F (104)

22

µ

F

CAPACITORS

Description

Disc

Mylar (large brown)

Mylar (small yellow)

Electrolytic (Lytic)

Value

9013

SEMICONDUCTORS

Description

Transistor 2SC9013

MISCELLANEOUS

Part #

351166

500007

512666

540004

590009

Qty.

Description

1 Battery Snap (Batt)

1 LCD Housing

1 LCD Cover

1 Label Top

1 Solder

Part #

161000

162000

162200

164700

171000

Part #

221017

251017L

251017S

272244S

Part #

329013

Part #

590098

629015

629016

723051

9ST4A

Resistor

Capacitors

C1

Diode

Disc Mylar Lytic

PARTS IDENTIFICATION

PC Board Liquid Crystal Display (LCD)

Transistor

Zebra

Display

Cover

Display

Housing

LCD

Label Top

-10-

ASSEMBLE THE FOLLOWING COMPONENTS TO THE PC BOARD

In all of the following steps the components must be installed either on the top or bottom legend sides of

the PC board as indicated. The board is turned to solder the component leads on the opposite side

(installed on Bottom, soldered on Top, installed on Top, soldered on Bottom).

Figure A Figure B Figure C Figure D

Lay resistor flat against the

PC board.

Negative (–) marking on capacitor

Flat

Side

White marking on PC board

Negative (–) marking on

PC board

Stand resistor on end as shown. Solder and cut off the excess leads.

Mount the capacitor with the negative (–) lead in the negative hole and the positive

(+) lead in the positive hole marked on the

PC board.

Mount the capacitor flat against the PC board as shown.

Marking on PC board

Mount the transistor with the flat side in the same direction as the

PC board marking.

R8 - 470k

Ω

5% 1/4W Res.

(yellow-violet-yellow-gold)

(see Figure A)

C6 - 22

µ

F Lytic Capacitor

(see Figure B)

R4 - 100k

Ω

5% 1/4W Res.

(brown-black-yellow-gold)

(see Figure A)

C5 - 100pF (101) Discap

R3 - 200k

Ω

5% 1/4W Res.

(red-black-yellow-gold)

(see Figure A)

C4 - .1

µ

F (104) Mylar Cap.

(small yellow)

C3 - .1

µ

F (104) Mylar Cap.

(small yellow)

R2 - 1M

Ω

5% 1/4W Res.

(brown-black-green-gold)

(see Figure A)

Bottom Legend Side

R7 - 470k

Ω

5% 1/4W Res.


(see Figure A)

T1 - 2SC9013 Transistor

(see Figure C)

R5 - 100k

Ω

5% 1/4W Res.


(see Figure D)

R6 - 1M

Ω

5% 1/4W Res.


(see Figure A)

R9 - 470k

Ω

5% 1/4W Res.


(see Figure A)

C1 - .1

µ

F (104) Mylar Cap.

(large brown)

R1 - 220k

Ω

5% 1/4W Res.

(red-red-yellow-gold)

(see Figure A)

C2 - .1

µ

F (104) Mylar Cap.

(small yellow)

Mount switch in direction shown.

Assembled View

SW1 - Switch On/Off

(see Figure E)

BATT - 9V Battery Snap

(see Figure E)

Insert the switch into the

PC board in the location shown. Make sure that the notch on the switch is in the same direction as the marking on the

PC board.

Figure E

Notch

Top Legend Side

-11-

Insert the 9V battery wires through the hole of the PC board as shown.

Solder and cut off the excess leads.

Black Wire

Red Wire

ASSEMBLE THE LCD

Assemble the LCD into the housing with the parts shown in Figure F. Note the top of the house is curved.

Wipe off zebra edges with a lint-free cloth and then insert the zebra into the top slot of the housing.

The LCD must be put in with the notch in the direction shown in Figure F. Peel off the clear protective film on top of the LCD (see Figure F), then place the LCD into the housing.

Place the display cover on top of the housing and press down to snap into place.

Place the LCD housing on top of the PC board as shown.

Figure F

LCD Cover

Notch

LCD

Do not touch edge

Zebra

Testing Procedure

The LCD housing will not be screwed to the PC board for this test. Align the LCD housing holes with those in the PC Board and hold in place. You can also use a rubber band to hold the housing. You will need to apply pressure so the zebra makes contact to the copper pads.

1. Place the top label over the knob. This will assist in obtaining the correct knob position.

2. Connect the 9V battery to the battery snap

3. Turn the meter on by pressing the power switch

(down position).

4. Align the LCD housing holes with those in the PC

Board and hold in place. You can also use a rubber band to hold the housing. You will need to apply pressure so the zebra makes contact to the copper pads.

5. Set the selector switch to the 200

Ω position. The first decimal point should light and show a 200 under it.

Select the 20k

Ω position and the second decimal points lights with a 20 under it.

Select the 2k

Ω position and the second decimal points lights with a 2 under it. Adjust the selector to other ranges and check that correct decimal point lights.

The LCD will display random numbers.

If the tests are not working, check for cold solder joints, part values and if the LCD is assembled correctly.

DO NOT PROCEED TO SECTION B

WITHOUT INSTRUCTOR’S APPROVAL.

Battery

LCD Housing

Clear Protective Film

Tape

PC Board

Figure G

Range Selector

Knob Assembly

-12-

SECTION B

DC Voltage & Current Circuit

PARTS LIST - SECTION B

Qty.

Symbol

1 R23

1 R22

1 R21

1 R20

1 R18

1 R32

1 R31

2 R17, R19

1 R33

1 R16

1 R30

1 R15

1 R14

4 R10-R13

1 VR1

Description

.01

Ω

0.99

Ω

0.5% 1/4W

9

Ω

0.5% 1/4W

90

Ω

0.5% 1/4W

100

Ω

0.5% 1/4W

390

Ω

1% 1/4W

900

Ω

1% 1/4W

900

Ω

0.5% 1/4W

5.6k

Ω

5% 1/4W

9k

Ω

0.5% 1/4W

13k

Ω

1% 1/4W

90k

Ω

0.5% 1/4W

900k

Ω

0.5% 1/4W

2.25M

Ω

0.5% 1/4W

200

Ω

(201)

RESISTORS

Color Code

Shunt wire black-white-white-silver-green white-black-black-silver-green white-black-black-gold-green brown-black-black-black-green orange-white-black-black-brown white-black-black-black-brown white-black-black-black-green green-blue-red-gold white-black-black-brown-green brown-orange-black-red-brown white-black-black-red-green white-black-black-orange-green red-red-green-yellow-green

Pot (lay down)

Note: Resistor tolerance (last band) of 5-band resistors may be blue instead of green.

Qty.

Symbol

2 D1, D2

1 T2

Value

1N4001

2SA9013

SEMICONDUCTORS

Description

Diode

9013

Qty.

Symbol

1

2

2

4

MISCELLANEOUS

Description

Fuse 0.2A 250V 5 x 20mm

Screw 2.5 x 8mm

Fuse Clips

Input Socket (10A,

µ

A/mA, COM, V

Ω

CAP)

Shunt Wire

PARTS IDENTIFICATION

Pot (lay down) Fuse Fuse Clip

Input Socket

Part #

100166

109950

119050

129050

131050

133930

139030

139050

145600

149050

151330

159050

169050

172250

191320

Part #

314001

329013

Part #

530020

642239

663004

664066

-13-


In all of the following steps the components must be installed either on the top or bottom legend sides of

the PC board as indicated. The board is turned to solder the component leads on the opposite side

(installed on Bottom, soldered on Top, installed on Top, soldered on Bottom).

Figure H

Stand diode on end. Mount with band as shown on the top legend.

Figure I

Band

White marking on PC board

Stand resistor on end as shown.

Solder and cut off the excess leads.

D1 - 1N4001 Diode

D2 - 1N4001 Diode

(see Figure H)

R19 - 900

Ω

.5% 1/4W Res.

(white-blk-blk-blk-green)

(see Figure I)

R20 - 90

Ω

.5% 1/4W Res.

(white-blk-blk-gold-green)

(see Figure I)

R21 - 9

Ω

.5% 1/4W Res.

(white-blk-blk-silver-green)

(see Figure I)

R22 - 0.99

Ω

.5% 1/4W Res.

(blk-wht-wht-silver-green)

(see Figure I)

R33 - 5.6k

Ω

5% 1/4W Res.

(green-blue-red-gold)

(see Figure I)

R30 - 13k

Ω

1% 1/4W Res.

(brn-orange-blk-red-brn)

(see Figure I)

R31 - 900

Ω

1% 1/4W Res.

(white-blk-blk-blk-brown)

(see Figure I)

VR1 - 200

Ω

Pot

(201)

Top Legend Side

See Page 21 for Assembled View

R15 - 90k

Ω

.5% 1/4W Res.

(white-blk-blk-red-green)

(see Figure I)

R14 - 900k

Ω

.5% 1/4W Res.

(white-blk-blk-orange-green)

(see Figure I)

R10 - 2.25M

Ω

.5% 1/4W Res.

R11 - 2.25M

Ω

.5% 1/4W Res.

R12 - 2.25M

Ω

.5% 1/4W Res.

R13 - 2.25M

Ω

.5% 1/4W Res.

(red-red-green-yellow-green)

(see Figure I)

R18 - 100

Ω

.5% 1/4W Res.

(brown-blk-blk-blk-green)

(see Figure I)

R17 - 900

Ω

.5% 1/4W Res.

(white-blk-blk-blk-green)

(see Figure I)

T2 - 9013 Transistor

(see Figure C)

R16 - 9k

Ω

.5% 1/4W Res.

(white-blk-blk-brown-green)

(see Figure I)

R23 - Shunt Wire

1/4” PC Board

Fuse Holder Clips

Fuse 0.2A 250V

Mount holders with the tab side as shown on the bottom legend side, solder into place and then insert fuse.

Tab

R32 - 390

Ω

1% 1/4W Res.

(orange-wht-blk-blk-brown)

(see Figure I)

Tab


-14-

Insert the four input sockets into the PC board holes and then solder the sockets in place.

Apply enough heat to allow the solder to flow around the input sockets (see Figure J).

Solder

Input Sockets

Socket

Attach the LCD to the PC board using the two

2.5 x 8mm screws. Use the two top mounting hole and lightly tighten the screws. The screws will be removed to assembly the next section.

Figure K

2.5 x 7.5

Screws

Bottom Legend Side

Figure J


Voltage Test

1. Place the top label over the knob and turn the range selector knob to the 20V position.


3. Connect the test leads (red lead to V

Ω

CAP and black to COM). Turn the meter on by pressing the power switch.

4. Using another meter of known accuracy, measure a DC voltage less than 20V (such as a

9 volt battery). You will calibrate the kit meter by measuring the same voltage source and adjusting VR1 until the kit meter reads the same as the accurate meter. When the two meters agree, the voltage circuit is calibrated. Turn the meter off and continue to the Current Test.

If the tests are not working, check components

R10 – R24, R30 – R33, VR1, and the transistor

T2.

Current Test

1. Turn the range selector knob to the 200

µ

A position.

2. Connect the test leads (red lead to

µ

A/mA and black to COM).

3. Connect the kit meter and another meter of known accuracy in series. Set the both meters in the 200

µ

A position. Construct a circuit for a DC current (for example 9V and a 47k

Ω resistor for

190

µ

A) and measure the circuit.

Both meters should have close to the same readings. Check the other DC current (2mA - 200mA) scales. The

20A scale requires a circuit of 1 - 20 amps.

If the meters do not agree, check the parts just added. Do not readjust VR1 for this will change the voltage reading set in step 1. If the tests are not working, check for cold solder joints and part values.

4. Turn the meter off and remove the battery, top label, and test leads DO NOT PROCEED TO

SECTION C WITHOUT YOUR INSTRUCTOR’S

APPROVAL.

5. Remove two display mounting screws and display by unscrewing the two mounting screws.

-15-

SECTION C

AC Voltage & Current Circuit

PARTS LIST - SECTION C

Qty.

1

1

Symbol

R38

R37

Description

1.87k

Ω

1% 1/4W

3k

Ω

1% 1/4W

6.8k

Ω

5% 1/4W 1 R39

1 R34 100k

Ω

5% 1/4W

2 R35, R36 100k

Ω

1% 1/4W

1 VR2 200

Ω

RESISTORS

Color Code

brown-gray-violet-brown-brown orange-black-black-brown-brown blue-gray-red-gold brown-black-yellow-brown brown-black-black-orange-brown

Trim Pot

Note: Resistor tolerance (last band) of 5-band resistors may be blue instead of green.

Qty.

Symbol

1 C7

1 C10

2 C8, C9

1 C11

CAPACITORS

Value Description

470pF (471)

.33

10

µ

µ

F (334)

4.7

µ

F

Disc

Mylar (large brown)

Electrolytic (Lytic)

(Lytic)

Qty.

Symbol

3 D3 - D5

1 IC2

Qty.

Symbol

Value

1N4148

LM324

Value

SEMICONDUCTORS

Description

Diode (glass)

Op-Amp

MISCELLANEOUS

Description

Part #

141830

143030

146800

161000

161030

191320


Figure L

Stand diode on end.

Mount with band as shown on the top legend.

D3

D5

D4

R37 - 3k

Ω

1% 1/4W Res.

(orange-blk-blk-brn-brn)

(see Figure I)

D4 - 1N4148 Diode

D5 - 1N4148 Diode

(see Figure L)

C8 - 4.7

µ

F Lytic Capacitor

(see Figure B)

C10 - .33

µ

F (334) Mylar Cap.

(may be marked 334)

D3 - 1N4148 Diode

(see Figure L)

C7 - 470pF (471) Discap


Assembled View

R38 - 1.87k

Ω

1% 1/4W Res.

(brn-gray-violet-brn-brn)

(see Figure I)

C9 - 4.7

µ

F Lytic Capacitor

(see Figure B)

R35 - 100k

Ω

1% 1/4W Res.

(brown-blk-blk-yellow-brown)

(see Figure I)

R36 - 100k

Ω

1% 1/4W Res.

(brown-blk-blk-yellow-brown)

(see Figure I)

-16-

Part #

224717

253318L

264747S

271015S

Part #

314148

330324

Part #


Figure M

Insert the IC socket into the PC board with the notch in the same direction marked on the top legend.

Solder the IC socket into place.

Insert the IC into the socket with the notch in the same direction as the notch on the socket.

IC

Notch

Top Legend Side

R39 - 6.8k

Ω

5% 1/4W Res.

(blue-gray-red-gold)

(see Figure I)

C11 - 10

µ

F Lytic Capacitor

(see Figure B)

VR2 - 200

Ω

Pot (201)

R34 - 100k

Ω

5% 1/4W Res.

(brown-black-yellow-brown)

(see Figure I)

IC Socket 14-pin

IC2 - LM324 Op-Amp IC

(see Figure M)

Socket

PC Board

Assembled View

PARTS LIST - SECTION D

SECTION D

Resistance & Buzzer Circuit

Qty.

Symbol

1 R54

1 R52

2 R55, R57

4 R51,53,56,58

1 PTC

Description

10k

Ω

5%

100k

Ω

5%

330k

Ω

5%

1M

Ω

5%

1.5k

Ω

Qty.

Symbol Value

2 C16, C17 .001

µ

F (102)

Qty.

Symbol

1 Buz

Value

RESISTORS

Color Code

brown-black-orange-gold brown-black-yellow-gold orange-orange-yellow-gold brown-black-green-gold

Thermister

CAPACITORS

Description

Discap

MISCELLANEOUS

Description

Buzzer (20mm dia.)

-17-

Part #

151000

161000

163300

171000

190416

Part #

231036

Part #

595220


R58 - 1M

Ω

5% 1/4W Res.

R51 - 1M

Ω

5% 1/4W Res.


(see Figure I)

R55 - 330k

Ω

5% 1/4W Res.

(orange-orange-yellow-gold)

(see Figure I)

R52 - 100k

Ω

5% 1/4W Res.


(see Figure I)

R54 - 10k

Ω

5% 1/4W Res.

(brown-black-orange-gold)

(see Figure I)

C17 - .001

µ

F (102) Discap

C16 - .001

µ

F (102) Discap

R57 - 330k

Ω

5% 1/4W Res.

(orange-orange-yellow-gold)

(see Figure I)

R53 - 1M

Ω

5% 1/4W Res.


(see Figure I)

PTC - 1.5k

Ω

Thermister

Top Legend Side

Assembled View

Buzzer

Solder

Points

Figure N

Solder the buzzer to the PC board in the locations shown. Then solder a discarded resistor lead to the middle of the buzzer and to the point shown on the PC board. Finally, solder the edge of the buzzer to the other point shown on the PC board.

Solder

Discarded

Resistor

Lead

BUZ - Buzzer

(see Figure N)

R56 - 1M

Ω

5% 1/4W Res.


(see Figure I)

Solder

Solder

Points


PC Board

Attach the LCD to the PC board using the two 2.5 x 8mm screws. Use the top-mounting hole and lightly tighten the screws. The screws will be removed to assemble the next section.


1. Place the top label over the knob and turn the range selector knob to an OHM scale position.



Ω


4. Test the Ohms, Buzzer, and Diode functions using the procedures below.

OHMs - Using two or three different value resistors, check each scale. Compare the kit meter readings with another meter of known accuracy. If the tests are not working, check the solder of the PTC.

Buzzer - Set the selector knob to the Buzzer ( ) position.

Short the red and black leads and the buzzer should sound. If the buzzer does not sound, check components R51-R58, PTC, C16, C17, and the solder connections to the buzzer.

Diode - Connect a diode to the test leads with the correct polarity (see figure below). The meter will range for 100 - 950.

COM

5. Turn the meter off and remove the battery, top label, and test leads

6. Remove two display mounting screws and display by unscrewing the two mounting screws.

DO NOT PROCEED TO SECTION E WITHOUT INSTRUCTOR’S APPROVAL.

-18-

V

Ω

SECTION E

Capacitance and Transistor Testing Circuit

PARTS LIST - SECTION E

Qty.

1

1

1

1

1

1

1

1

1

2

1

1

1

2

1

1

Symbol

R29

R28

R45

R27

R42

R43

R26

R44

R47

R40, R41

R46

R25

R48

R49, R50

R24

VR3

Description

10

Ω

1% 1/4W

90

Ω

1% 1/4W

150

Ω

1% 1/4W

900

Ω

1% 1/4W

1.91k

Ω

1% 1/4W

4.3k

Ω

1% 1/4W

9k

Ω

1% 1/4W

10k

Ω

1% 1/4W

11k

Ω

1% 1/4W

39k

Ω

1% 1/4W

76.8k

Ω

1% 1/4W

90k

Ω

1% 1/4W

160k

Ω

1% 1/4W

220k

Ω

5% 1/4W

900k

Ω

1% 1/4W

200

Ω

(201)

RESISTORS

Color Code

brown-black-black-gold-brown white-black-black-gold-brown brown-green-black-black-brown white-black-black-black-brown brown-white-brown-brown-brown yellow-orange-black-brown-brown white-black-black-brown-brown brown-black-black-red-brown brown-brown-black-red-brown orange-white-black-red-brown violet-blue-gray-red-brown white-black-black-red-brown brown-blue-black-orange-brown red-red-yellow-gold white-black-black-orange-brown

Trim Pot

Note: Resistor tolerance (last band) of 5-band resistors may be green instead of brown.

Qty.

Symbol Value

4 C12 - C15 .01

µ

F (103)

Qty.

Symbol

4 D6 - D9

1 IC3

Qty.

Symbol

1

2

Value

1N4001

LM324

Value

CAPACITORS

Description

Mylar (large brown)

SEMICONDUCTORS

Description

Diode

Op-Amp

MISCELLANEOUS

Description

IC Socket 14-pin h

FE

Socket

Part #

241017L

Part #

314001

330324

Part #

664014

664015

Part #

121030

129030

131530

139030

141930

144330

149030

151030

151130

153930

157630

159030

161630

162200

169030

191320

-19-


IC Socket 14-pin

IC3 - LM324 Op-Amp IC

(see Figure M)

R45 - 150

Ω

1% 1/4W Res.

(brn-green-blk-blk-brn)

(see Figure I)

VR3 - 200

Ω

Pot

R47 - 11k

Ω

1% 1/4W Res.

(brn-brn-blk-red-brn)

(see Figure I)

R46 - 76.8k

Ω

1% 1/4W Res.

(violet-blue-gray-red-brn)

(see Figure I)

C14 - .01

µ

F (103) Mylar Cap.

R48 - 160k

Ω

1% 1/4W Res.

(brn-blue-black-orange-brn)

(see Figure I)

C15 - .01

µ

F (103) Mylar Cap.

D6 - 1N4001 Diode

D7 - 1N4001 Diode

(see Figure O)

R29 - 10

Ω

1% 1/4W Res.

(brn-blk-blk-gold-brn)

(see Figure I)

R24 - 900k

Ω

1% 1/4W Res.

(white-black-black-org-brown)

(see Figure I)

R25 - 90k

Ω

1% 1/4W Res.

(white-black-black-red-brown)

(see Figure I)

R26 - 9k

Ω

1% 1/4W Res.

(white-black-black-brn-brn)

(see Figure I)

R27 - 900

Ω

1% 1/4W Res.

(white-blk-blk-blk-brown)

(see Figure I)

R28 - 90

Ω

1% 1/4W Res.

(white-blk-blk-gold-brown)

(see Figure I)

R43 - 4.3k

Ω

1% 1/4W Res.

(yellow-orange-blk-brn-brn)

(see Figure I)

R42 - 1.91k

Ω

1% 1/4W Res.

(brn-white-brn-brn-brn)

(see Figure I)

R40 - 39k

Ω

1% 1/4W Res.

R41 - 39k

Ω

1% 1/4W Res.

(orange-white-blk-red-brn)

(see Figure I)

Top Legend Side


h

FE

- Sockets - Install

these with no more than

0.4” of height from the PC board to the top of the sockets. Otherwise, the top case will not fit together properly with the bottom case.

0.4”

R49 - 220k

Ω

5% 1/4W Res.

R50 - 220k

Ω

5% 1/4W Res.

(red-red-yellow-gold)

(see Figure I)

D8 - 1N4001 Diode

D9 - 1N4001 Diode

(see Figure O)

Figure O

Stand diode on end. Mount with band as shown on the top legend.

D6

D7

D8

D9

Figure P

Lay resistor flat against the PC board.

R44 - 10k

Ω

1% 1/4W Res.

(brn-blk-blk-red-brn)

(see Figure P)

C13 - .01

µ

F (103) Mylar Cap.

C12 - .01

µ

F (103) Mylar Cap.

-20-

Assembled View for Section B

Attach the LCD to the PC board using the two 2.5

x 8mm screws. Use the top-mounting hole and lightly tighten the screws.


Capacitance

1. Place the top label over the knob and turn the range selector knob to a capacitance (C) scale position.

2. Connect the 9V battery to the battery snap.

3. Connect the short test leads (red lead to V

Ω

CAP and black to COM).

Turn the meter on by pressing the power switch.

4. Capacitance - Measure a cap with another meter and then connect the capacitor to the meter leads. Adjust VR3 so that the meter reads the same as the accurate one. This calibrates capacitance circuit of meter. Using two or three different value capacitors, check each scale. If the test is not working check components R40-

R48, VR3, C12 –C15, D6 - D9, and IC3.

Assembled Views for Section E

Transistor - Set the meter in the h

FE scales. Place an NPN transistor into the socket. Make sure that the transistor is in correctly. Depending on the type of transistor, the meter will range from 20 to 550.

Place a PNP transistor into the PNP socket; the range will also be 20 to 550. If the tests are not working, check components R49 – R50, and the transistor sockets.

5. Turn the meter off and remove the battery, top label, and test leads.

DO NOT PROCEED TO SECTION F WITHOUT INSTRUCTOR’S APPROVAL.

-21-

SECTION F

Final Assembly

PARTS LIST - SECTION F

Qty.

Description

1 Button (red)

3 Sleeve Input Socket (yellow)

1 Sleeve Input Socket (red)

1 Case Top

1 Case Bottom

1 Cover Battery

2 Screw LCD Housing 2.5 x 8mm

Note: The shield may be installed already.

Part #

622027

622660

622661

623112

623203

623210

642239

FINAL ASSEMBLY

Solder the spring to the PC board as shown in

Figure Q.

Install the bottom two 2.5 x 8mm screws to the

LCD housing as shown in Figure R.

Peel off the protective backing on the top label

(A) and bottom label (B) and stick them to the top case as shown in Figure S.

Place the PC board into the bottom case. Feed the battery clip through the case as shown in

Figure T.

Place the four colored sleeves over the input sockets as shown in Figure T. Note that the black sleeve goes on the COM socket.

Qty.

Description

2 Screw Case 3 x 17.5mm

1 Spring

1 Label Bottom

1 Shield Label

1 Holster

1 Test Leads Alligator

1 Test Leads Red-Black

Part #

642240

680033

723052

780012

9C72

9TL13

9TL14

Place the red power cap onto the switch SW1 as shown in Figure T.

Solder

Spring

Figure Q

Bottom Label (B) Top Label (A)

2.5 x 8mm Screws

Figure R

-22-

Figure S

Figure T

Top Case

Input Socket

Sleeves

Battery Snap

Feed the battery snap through this opening.

PC Board

Shield Label

Black

Red Power Cap

Bottom Case

-23-

FINAL ASSEMBLY (continued)

Feed the battery snap wires through the slot on the top case as shown in Figure U.

Connect the battery and place it in the cavity of the top case as shown in Figure V.

Battery Snap Wires Slot

Place the battery cover onto the case as shown in Figure V. Hold the two sections together with two M3 x 17.5 screws.

M3 x 17.5 Screws

Battery Cover

Figure U

Battery

Figure V

Testing Procedure SECTION C - AC voltage and current circuit

1. Set range selector knob to an AC Volt scale position.


Ω


3. Measure an AC voltage with a known accurate meter.

Now measure the voltage with the kit meter. The meters should be the same voltage.

Current Test

1. Turn the range selector knob to the 200

µ

A position.

-24-

2. Connect the test leads (red lead to

µ

A/mA and black to COM).

Connect the kit meter and another meter of known accuracy in series. Set the meters in the 200

µ

A position. Construct a circuit for an AC current and measure the circuit current.

Both meters should have close to the same readings. If the meters do not agree, check the parts just added. Do not readjust VR1 this will change the voltage reading set in step 1. Check the 2m - 200mA scales. The 20A scale requires a circuit of 1 - 20 amps. If the tests are not working, check for cold solder joints and part values

TROUBLESHOOTING GUIDE

If the meter is not working, perform the U1 (7106)

Voltage Test first. This test is to verify that the IC and Reference Voltage are operational.

Then

U1 (7106) Voltage Test

1. Measure the voltage across pin 8 and pin 34 on

U1 (7106) for 9V.

A. Check the battery and SW1 connections.

B. Check for a 9V and GND short.

1. One of the ICs may be bad. Remove one IC at a time and check voltage again between pins 8 and 34.

2. Measure the voltage from pin 8 to COM on U1 for

3V.

A. U1 is defective.

3. Check the Main Oscillator on U1 (7106) pins 6, 7, and 4.

Pin 6 perform the tests that pertain to the Function that is not working on your meter.

Voltage/OHM Section

1. Measure across V

Ω

CAP terminal and COM terminal for 10M

Ω

(set meter in 200mV) battery installed.

A. Lower or higher than 10M

Ω

.

1. Check resistors R10 - R18.

2. LCD readings floating.

A. Measure from COM terminal to pin 43 on

U1 (7106) for 220k

Ω

.

1. R3 open or defective.

AC Voltage Section

1. Apply 15VAC to meter and measure pin 14 of U2

(324) to COM terminal with a scope (meter on

20VAC scale).

Pin 14 to COM 2Vpp

Pin 7

Pin 4

4. Measure the voltage from pin 44 to COM on U1

(7106) = 0.1V.

A. Adjust VR1 so the the junction of R31,

R33 and VR1 equal to 100mV.

1. Can’t set to 100mV.

a. VR1 wrong value or defective.

b. R30 - R32 wrong value.

A. Check IC2 and R34

2. Check junction R39 and C11 of U1 (7106) with a scope.

.03Vpp

Waveform for junction R39 and C11.

.16Vpp

0V

A. Check R35 - R39, C7 - C11, D3 - D5, and

VR2.

-25-

Amps Section

1.

µ

A/mA scale not working:

A. Check fuse.

B. Measure across (

µ

A/mA) terminal and

(COM) terminal and check the following settings:

200

µ

= 1k

Ω

20m = 10

Ω

2m = 100

200m = 1

Ω

Ω

1. Lower or higher check R19 - R23.

2. 10A scale not working:

A. Check shunt.

Capacitance Section

1. Connect the .1

µ

F cap to the meter and check pin

14 and pin 1 of U2 with a scope (meter set to 2N).

Pin 14 350Hz - 400Hz 5Vpp.

Pin 1 350Hz - 400Hz .14Vpp.

A. No signal at pin 14.

1. Check R40 - R43, C12, C13, and IC3.

B. No signal at pin 1 but present at pin 1.

1. Check R44, R45, VR1, D6, and D7.

Pin 8 350Hz - 400Hz .3Vpp.

h

FE

Section

1. Check for shorts on socket pins.

2. Measure across base (B) terminal to COM terminal for 209k

Ω to 231k

Ω

.

A. Lower or higher than value; Check R49

(NPN) and R50 (PNP).

Decimal Point Section

1. Displays two decimal points.

A. Shorted resistors R7 - R9.

2. No decimal points displayed.

A. Check R7 - R9.

Diode

1. Measure voltage across V OHM and COM terminal (set in diode mode) = 3V.

A. Low voltage, check R51, R53, and R54.

Buzzer

U2 Voltages

No Sound

Pin 1

–5.5

Pin 2

Pin 3

Pin 4

Pin 5

Pin 6

Pin 7

–5.5

–5.5

3

0

3

–5.5

Pin 1

Pin 2

Pin 3

Pin 4

Pin 5

Pin 6

Pin 7

Sound

–1.87

–1.87

–1.87

3

0

0

1.87

Pin 1 of IC2 - 1.5kHz.

1.6Vpp

6V

C. No signal at pin 8.

1. Check R46 - R48, D8, D9, C14, and

C15.

-26-

REINSTALLATION OF THE RANGE SELECTOR KNOB

If you removed the rotary selector knob for troubleshooting, then follow the instructions below to reinstall it.

Slide Contact

Figure W

Place the PC board over the range selector knob and fasten the knob to the PC board with a M2.3 x 8 screw.

CAUTION:

Do not over-tighten the screw. The knob should be snug, but not loose. Turn back the M2.3 x 8 screw 1/2 turn. Slip the two shims under the knob (see

Figure W). If they do not slip in, turn back the screw another 1/4 turn. Tighten the screw just enough so that the shims can be pulled out. You should now have the proper tension to hold the knob and contacts in place and rotate the knob to the desired positions.

Spring

Ball Bearing

Bottom View of Selector Knob & Slide Contacts

Qty.

Description

1 Selector Switch 2 psc.

2 Selector Pin

Part #

622666

622666A

6 Slide Contacts 622666B

4 Screws - Selector Switch M1.8 x 8mm 622666C

Qty.

Description

4 Nut - Selector Switch M1.8

2 Ball Bearing

2 Spring - Selector

Part #

622666D

622666E

622666F

USING THE DIGITAL MULTIMETER

Familiarize yourself with your new digital meter by taking readings of known resistances and voltages.

You will find that the readings will not be as accurate on certain ranges for a given measurement. For example, when measuring a low resistance on a high range, the reading will show a short 0.00.

When measuring a high resistance on a low range, the reading will show infinity 1.

Likewise, it is important to use the correct range when measuring voltages.

Table 1 shows an example of the readouts for different values of resistance. Table 2 shows an example of the readouts for 117VAC and 100VDC.

The shaded area indicates the most accurate range.

It must be remembered that the readings will shift slightly when switching to a different range.

MEASURED

RESISTANCE

SHORT

(LEADS TOUCHING)

RANGE SETTING

200

Ω

2k

Ω

20k

Ω

200k

Ω

2M

Ω

*

00.1

INFINITY

47

Ω

270

Ω

10k

Ω

47k

Ω

470k

Ω

2.2M

Ω

1 .

52.1

1 .

1 .

1 .

1 .

1 .

* RESISTANCE OF TEST LEADS

.000

1.

.052

.267

1.

1.

1.

1.

0.00

1 .

0.05

0.26

10.18

Table 1

1 .

1 .

1 .

00.0

1 .

00.0

00.2

10.2

52.7

1 .

1 .

.000

1.

.000

.000

.010

.052

.472

1.

20M

Ω

0.00

1 .

0.00

0.00

0.01

0.05

0.47

2.12

Table 2

MEASURED

VOLTAGE

120VAC

100VDC

200mV

1 .

1 .

2V

1.

1.

-27-

20V

1 .

1 .

200V 1000V

120.0

100.0

120

100

1. FEATURES

• Wide measuring ranges: 34 ranges for AC/DC Voltage and Current, Resistance, Capacitance, TR h

FE

,

Diode Test, and Continuity Buzzer.

• 10M

Ω

Input Impedance

• Big LCD for easy reading

• Tilt Stand

• Rubber Holster

2. SPECIFICATIONS

2-1 General Specifications

Display 3 1/2 LCD 0.9” height, maximum reading of 1999.

Polarity

Overrange Indication

Low Battery Indication

Operating Temperature

Storage Temperature

Temperature Coefficient

Power

Battery Life (typical)

Dimensions (w/o holster)

Weight (w/o holster)

Accessories

Automatic “–” sign for negative polarity.

Highest digit of “1” or “–1” is displayed.

“BAT” lettering on the LCD readout.

0 O C to 50 O C.

less than 80% relative humidity up to 35

O

C.

less than 70% relative humidity from 35 O C to 50 O C.

–15 O C to 50 O C

0

O

C to 18

O

C and 28

O

C to 50

O

C.

less than 0.1 x applicable accuracy specification per degree C.

9V alkaline or carbon zinc battery (NEDA 1604).

100 hours with carbon zinc cells.

200 hours with alkaline cells.

3.55” (90.2mm) (W) x 7.6” (193mm) (L) x 1.78” (45.2mm) (H).

Approximately 10.4oz. (300g.)

Safety Test Leads 1 pair

2-2 Measurement Ranges (Accuracy: 1 year 18

O

C to 28

O

C)

DC Voltage

Range

200mV

2V

20V

200V

1000V

Resolution

100

µ

V

1mV

10mV

100mV

1V

Accuracy

+0.5% of rdg + 2dgt

+0.5% of rdg + 2dgt

+0.5% of rdg + 2dgt

+0.5% of rdg + 2dgt

+0.8% of rdg + 2dgt

Maximum Input

DC 1000V or peak AC

Normal Mode Rejection Ratio: Greater than 46dB at 50Hz 60Hz (1k unbalance)

-28-

AC Voltage

Range

200mV

2V

20V

200V

750V

Resolution

100

µ

V

1mV

10mV

100mV

1V

Accuracy

+1.5% of rdg + 2dgt

+1% of rdg + 2dgt

+1% of rdg + 2dgt

+1% of rdg + 2dgt

+1.5% of rdg + 2dgt

Resistance

Range

200

Ω

2k

Ω

20k

Ω

200k

Ω

2M

Ω

20M

Ω

Resolution

0.1

Ω

1

Ω

10

Ω

100

Ω

1k

Ω

10k

Ω

Maximum open circuit voltage: 2.8V

Accuracy

+1% of rdg + 2dgt

+0.8% of rdg + 2dgt

+0.8% of rdg + 2dgt

+0.8% of rdg + 2dgt

+0.8% of rdg + 3dgt

+2.0% of rdg + 4dgt

DC Current

Range

200

µ

A

2mA

20mA

200mA

20A

Resolution

100nA

1

µ

A

10

µ

A

100

µ

A

10mA

Accuracy

+1.5% of rdg + 2dgt

+1.5% of rdg + 2dgt

+1.5% of rdg + 2dgt

+2% of rdg + 2dgt

+2.5% of rdg + 3dgt

AC Current

Range

200

µ

A

2mA

20mA

200mA

20A

Resolution

100nA

1

µ

A

10

µ

A

100

µ

A

10mA

Capacitance

Range

2nF

2nF

200nF

2

µ

F

20

µ

F

200

µ

F

Resolution

1pF

10pF

100pF

1nF

10nF

100nF

Accuracy

+1% of rdg + 3dgt

+1% of rdg + 3dgt

+1% of rdg + 3dgt

+1.5% of rdg + 3dgt

+2.0% of rdg + 3dgt

Accuracy

+2.5% of rdg + 3dgt

+2.5% of rdg + 3dgt

+2.5% of rdg + 3dgt

+2.5% of rdg + 3dgt

+2.5% of rdg + 3dgt

+5% of rdg + 3dgt

-29-

Maximum Input

AC 750V maximum 50Hz - 400Hz

Test Current

Approximately

1.2mA

Protection

Protected by

250V/2A Fuse

Protection

Protected by

250V/2A Fuse

Protection

Test frequency 400Hz

Input Protection

Protected By

PTC

Transistor h

FE

Range

NPN

PNP

Test Condition

2mA 3V

2mA 3V

Diode Test

Measures forward resistance of a semiconductor junction in k Ohm at max. test current of 1mA.

3. OPERATION

3-1 Preparation and caution before measurement

1. If the function must be switched during a measurement, always remove the test leads from the circuit being measured.

4. In order to prevent damage or injury to the unit, never fail to keep the maximum tolerable voltage and current, especially for the 20A current range.

2. If the unit is used near noise generating equipment, be aware that the display may become unstable or indicate large errors.

5. Carefully inspect the test lead.

If damaged, discard and replace.

3. Avoid using the unit in places with rapid temperature variations.

3-2 Panel Description

LCD Display

On/Off Switch

Range Selector Knob h

FE

Input Socket

20A Input Jack

(200mA Max) A input Jack

Volt Ohm Cap Input Jack

Common Input Jack

-30-

3-3 Method of Measurement

(A) DC/AC Voltage Measurement

1. Connect the red test lead to “V

Ω

CAP” input jack and the black one to the “COM” jack.

2. Turn the meter on by pressing the power switch.

3. Set the range selector knob to the desired volt position. If the magnitude of the voltage is not known, set the range selector knob to the highest range and reduce until a satisfactory reading is obtained.

4. Connect the test leads to the device or circuit being measured.

5. Turn on the power to the device or circuit being measured. The voltage value will appear on the digital display along with the voltage polarity.

6. Turn off the power to the device or circuit being tested and discharge all of the capacitors prior to disconnecting the test leads.

(B) DC/AC Current Measurement

1. Connect the red test lead to the “A” input jack for current measurement up to 200mA, and the black one to “COM”.


3. Set the range selector knob to the desired “Amp” current position.

If the magnitude of current is not known, set the range selector knob to the highest range and reduce until a satisfactory reading is obtained.

4. Open the circuit to be measured, and connect the test leads in series with the load in which current is to be measured.

5. Read the current value on the digital display.

6. Turn off all power to the circuit being tested and discharge all of the capacitor prior to disconnecting the test lead.

7. To measure in the 10A range, use the “10A” jack as the input jack. Be sure to measure within 10 seconds to avoid high-current hazard.

(C) Resistance Measurement

1. Connect red test lead to the “V

Ω

CAP” input jack and the black one to “COM”.


3. Set the range selector knob to desired “Ohm” position.

4. If the resistance being measured is connected to a circuit, turn off the power to the circuit being tested and discharge all capacitors.

5. Connect the test leads to the circuit being measured. When measuring high resistance, be sure not to contact adjacent point even if insulated, because some insulators have a relatively low insulation resistance, causing the measured resistance to be lower than the actual resistance.

6. Read resistance value on digital display.

(D) Diode Test

1. Connect the red test lead to “V

Ω

CAP” input jack and the black one to the “COM” jack.


3. Set the range selector knob to the “ ” position.

4. If the semiconductor junction being measured is connected to the circuit, turn off the power to the circuit being tested and discharge all of the capacitors.

5. Connect the test leads to the device and read forward value on the digital display.

6. If the digital reads overrange (1), reverse the lead connections.

The placement of the test leads when the forward reading is displayed indicates the orientation of the diode.

The red lead is positive and the black lead is negative.

If overrange (1) is displayed with both lead connections, the junction is open.

-31-

(E) Transistor h

FE

Measurement

1. The transistor must be out of circuit. Set the rotary selector knob to the h

FE position.


3. Plug the emitter, base and collector leads of the transistor into the correct holes in either the NPN of the PNP transistor test socket, whichever is appropriate for the transistor you are checking.

4. Read the h

FE

(beta or DC current gain) on the display.

(F) Capacitance Measurement

1. Connect red test lead to the “V

Ω

CAP” input jack and the black one to “COM”.


3. Set the rotary selector knob to the “FARAD” position.

4. Set the rotary selector knob to the desired capacitance position.

5. Short the leads of the capacitor to be tested together to insure that there is no charge on the capacitor.

6. Connect the leads to the capacitor and read the capacitance value on the digital display.

4. OPERATION MAINTENANCE

4-1 Battery and Fuse Replacement

CAUTION

BEFORE ATTEMPTING BATTERY REMOVAL OR

REPLACEMENT, DISCONNECT THE TEST

LEADS FROM ANY ENERGIZED CIRCUITS TO

AVOID SHOCK HAZARD.

The fuse rarely needs replacement and blow almost always as a result of operator error. To replace the battery and fuse (200mA/250V), remove the two screws in the bottom of the case. Simply remove the old battery or fuse and replace with a new one.

Be sure to observe the polarity when replacing the battery.

5. SAFETY SYMBOLS

!

This marking adjacent to another marking or a terminal operating device indicates that the operator must refer to an explanation in the operating instructions to avoid damage to the equipment and/or to avoid personal injury.

WARNING

This WARNING sign denotes a hazard. It calls attention to a procedure, practice or the like, which if not correctly performed or adhered to, could result in personal injury.

CAUTION

This CAUTION sign denotes a hazard. It calls attention to a procedure, practice or the like, which if not correctly adhered to, could result in damage to or destruction of part or all of the instrument.

500V max.

This marking advises the user that the terminal(s) so marked must not be connected to a circuit point at which the voltage, with respect to earth ground, exceeds (in this case) 500 volts.

This symbol adjacent to one or more terminals identifies them as being associated with ranges that may in normal use be subjected to particularly hazardous voltages. For maximum safety, the instrument and its test leads should not be handled when these terminals are energized.

-32-

SCHEMATIC DIAGRAM

-33-

QUIZ

1. The function of the A/D converter is to . . .

A. convert digital to analog.

B. divide analog signal by 2.

C. convert analog to digital.

D. convert AC to DC.

2. What type of divider network is used for voltage measurements?

A. Divide by 20.

B. Capacitance.

C. Divide by 5.

D. Resistor.

3. When the AC voltage is measured, it is first . . .

A. divided down by 2.

B. converted to DC.

C. coupled to a halfwave rectifier.

D. low voltage.

4. When measuring current, the shunt resistors convert the current to . . .

A. +0.190 to –0.190.

B. –1.199 to +1.199.

C. –0.099 to +0.099.

D. –199 to +0.199.

5. Which IC drives the LCD?

A. 358.

B. LM324.

C. 7106.

D. 1N5232.

6. Resistance measurements are made by . . .

A. comparing voltage drops in the unknown resistor and a reference resistor.

B. measuring the current in the unknown resistor.

C. measuring the current in the reference resistor.

D. equalizing the voltage drop in the unknown and reference resistor.

7. Measurement cycles performed by the A/D converter can be divided into what types of time periods?

A. Long, short.

B. Auto zero, integrate, read.

C. Zero, read, interphase.

D. Autozero, read, cycle phase.

8. A resistor with band colors green-black-greenbrown-green is what value?

A. 50.5k

Ω

+ 5%.

B. 5.15k

Ω

+ 10%.

C. 5.05k

Ω

+ .5%.

D. 5.05k

Ω

+ 1%.

9. When checking a transistor, the selector knob should be in the . . .

A. farad position.

B. ohm position.

C. diode position.

D. h

FE position.

10. Where do the leads need to be on the meter when measuring 450mA?

A. 10A, COM.

B. V

Ω

CAP, COM.

C.

µ

A/mA, 10A.

D.

µ

A/mA, COM.

A D, 10.

C, 9.

, 8.

A, 7.B

C, 6.

B, 5.

B, 4.

D, 3.

, 2.

1.C

s: Answer

-34-

Elenco

TM

Electronics, Inc.

150 W. Carpenter Avenue

Wheeling, IL 60090

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

e-mail: [email protected]

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