Simpson 260 8XI User Manual

Simpson 260® Series 8XI

Volt-Ohm-Milliammeter

INSTRUCTION MANUAL

About this Manual
To the best of our knowledge and at the time written, the information contained in
this document is technically correct and the procedures accurate and adequate
to operate this instrument in compliance with its original advertised specifica­tions.

Notes and Safety Information

This Operator’s Manual contains warning headings which alert the user to check
for hazardous conditions. These appear throughout this manual where appli­cable, and are defined below. To ensure the safety of operating performance of
this instrument, these instructions must be adhered to.
Warning, refer to accompanying documents.

!

Warning. Refer to accompanying documents

Caution, risk of electric shock.

!

This instrument is designed to prevent accidental shock to the operator when
properly used. However, no engineering design can render safe an instrument
whick is used carelessly. Therefore, this manual must be read carefully and com­pletely before making any measurements. Failure to follow directions can result
in ser ious or fatal accident.

Shock Hazard: As defined in American National Standard, C39.5, Safety
Requrements for Electrical and Electronic Measuring and Controlling Instrumen­tation, a shock hazard shall be considered to exist at any part involving a poten­tial in excess of 30 volts RMS (sine wave) or 42.4 volts DC or peak and where a
leakage current from that part to ground exceeds 0.5 milliampere, when mea­sured with an appropriate measuring instrument defined in Section 11.6.1 of
ANSI C 39.5.

Technical Assistance

SIMPSON ELECTRIC COMPANY offers assistance Monday through Friday
7:30 am to 5:00 pm Central Time by contacting Technical Support or
Customer Service at [phone].
Internet: http://www.simpsonelectric.com

Warranty and Returns

SIMPSON ELECTRIC COMPANY warrants each instrument and other ar ticles
manufactured by it to be free from defects in material and workmanship under
normal use and service, its obligation under this warranty being limited to making
good at its factory or other article of equipment which shall within one (1) year
after delivery of such instrument or other article of equipment to the original
purchaser be returned intact to it, or to one of its authorized service centers, with
transportation charges prepaid, and which its examination shall disclose to its
satisfaction to have been thus defective; this warranty being expressly in lieu of
all other warranties expressed or implied and of all other obligations or liabilities
on its part, and SIMPSON ELECTRIC COMPANY neither assumes nor autho­rizes any other persons to assume for it any other liability in connection with the
sales of its products.

This warranty shall not apply to any instrument or other article of equipment
which shall have been repaired or altered outside the SIMPSON ELECTRIC
COMPANY factory or author ized service centers, nor which has been subject to
misuse, negligence or accident, incorrect wiring by others, or installation or use
not in accord with instructions furnished by the manufacturer.

260® is a Registered Trademark of the Simpson Electric Company.

2

NOTES:

3

Contents

1. INTRODUCTION ............................................................................ 7

1.1 General Description ........................................................................ 7

1.2 Overload Protection ........................................................................ 7

1.3 Internal Batteries ............................................................................. 7

1.4 Printed Circuit ................................................................................. 8

1.5 Case................................................................................................8

1.6 Adjust-A-Vue Handle ...................................................................... 8

1.7 Test Leads ....................................................................................... 8

1.8 Technical Data ................................................................................ 8

1.9 Definition of Accuracy ................................................................... 1 0

1.10 Safety Considerations .................................................................. 10

1.11 Audio Alarm .................................................................................. 10

1.12 Accessories...................................................................................10

1.13 Additional Accessories ................................................................. 1 1

1.13.1 Accessory DC High Voltage Probes .............................................. 11

1.13.2 Accessory AC High Voltage Probe ................................................ 11

1.13.3 Amp-Clamp Model 150-2 ............................................................... 11

2. INSTALLATION............................................................................. 12

2.1 Unpacking and Inspection ............................................................ 1 2

2.2 Warranty........................................................................................12

2.3 Shipping........................................................................................12

2.4 Power Source Requirements ........................................................ 12

2.5 Operating Position ........................................................................ 1 2

3. CONTR OLS, JA CKS AND INDICA T ORS...................................... 13

3.1 Front Panel Description ................................................................ 1 3

4. OPERATION ................................................................................ 14

4.2 Safety Precautions ........................................................................14

4.3 Polarity Reversing ......................................................................... 16

4.4 Measurement of Unknown Voltage or Current ............................16

4.5 Test Leads ....................................................................................16

4.6 DC Voltage Measurement.............................................................1 6

4.6.1 DC Voltage Measurement 0-250 mV Range ................................ 16

4.6.2 DC Voltage Measurement 0-2.5 Through 0.250V Range.............. 17

4.6.3 DC Voltage Measurement 0-500V Range ..................................... 17

4.6.4 DC Voltage Measurement 0-1000V Range ................................... 1 8

4.7 AC Voltage Measurement ............................................................ 1 9

4.7.1 AC Voltage Measurement 0-2.5 Through 0-250V Range............. 19

4.7.2 AC Voltage Measurement 0-500V Range...................................... 20

4.7.3 AC Voltage Measurement 0-1000 Range ...................................... 21

4.7 Output Voltage Measurement .......................................................21

4.8 Decibel Measurement (-20 to +50 dB) .........................................2 2

4.9 Direct Current Measurement ........................................................ 23

4.9.1 Direct Current Measurement 0-50µA Range ................................ 24

4.9.2 Direct Current Measurement 0-1mA through 0-500mA Range ... 24

4.9.3 Direct Current Measurement 0-10A Range .................................. 25

4.10 Zero Ohms Adjustment .................................................................25

4.11 Measuring Resistance .................................................................. 2 6

4.12 Resistance Measurement of Semiconductors .............................. 26

4.13 Continuity Tests .............................................................................27

4

Contents, Continued

5 OPERA T OR SERVICING.............................................................. 28

5.1 Battery and Fuse Replacement .................................................... 2 8

5.2 Fuse Protection ............................................................................. 29

5.3 Care ..............................................................................................29

6 PARTS LIST AND SCHEMATIC DIAGRAM.................................. 3 0

6.1 Removing the Instrument Case. ...................................................3 0

6.2 Replacement Parts and Schematic Diagram ............................... 3 0

5

NOTES:

6

1. INTRODUCTION

1.1 General Description

The Simpson Volt-Ohm-Milliammeter 260 Series 8XI, (hereafter referred to as the
260 or as the Instrument) is a rugged, accurate, compact, easy-to-use instrument
equipped with mirrored dial to eliminate parallax. The Instrument can be used to
make accurate measurements of AC and DC voltage, direct current, resistance,
decibels, and Output Voltage. The Output Voltage function is used for measuring
the AC component of a mixture of AC and DC voltage. This occurs primarily in
amplifier circuits.

New Features in the 260 are:

0 - 25V AC/DC Range
Continuity Test Alarm
I

ndividual Dual Jacks for the 500V AC/DC and 1000V AC/DC Ranges

High Impact Case (Yellow)

1.2 Overload Protection

No single protective device nor even a combination of devices as found in the
260 can fully protect a multi-purpose Instrument under all overload conditions.
Despite all the built-in protection provided, overloads severe enough to damage
the Instrument are possible when the Instrument is misused.

The fuse in the 260 affords maximum Instrument protection under overload con­ditions which might occur within the measuring capabilities of the Instrument,
however, the operator must exercise care to avoid severe overloads, particularly
when working in high voltage circuits.

Basic overload protection is provided by a small inexpensive, and easily obtain­able 3 AG type, 1 ampere, quick-blow fuse. This fuse is rated to interrupt circuit
voltages up to 250 volts. For maximum protection it is important to replace the 1A
fuse with the Littlefuse type 312001 only.

A supplemental high energy fuse is provided for additional protection from se­vere overloads. This fuse is rated for an interruption capacity of 10,000 amperes
up to 600 volts. (Littlefuse T ype BLS or Bussman Type BBS). If the Instrument fails
to indicate a reading, the 1 Amp or the 2 Amp fuse may be burned out. (Refer to
paragraph 5.2 for fuse replacement.) A 1 Amp spare fuse is furnished with each
Instrument. Fuses are located in the battery and fuse compartment.

NOTE: The 0-10A range is not fused. The shunt connects directly to the -10A and
+10A jacks.

T wo diodes connected across the meter mo vement affords protection to the mo ve­ment by circumventing excessive current around the movement in the event of an
overload.

1.3 Internal Batteries

There are two batteries in the ohmmeter circuits. One is a NEDA 13F size D cell
that furnishes 1.5-volts for the R X 1 and R X 100 ranges. A NEDA 1604A alkaline
battery furnishes 9-volts for the R X 10,000 range. The 1.5-volt D cell is held in
place with two spring clips which also serve as battery contacts. The polarity
symbols for the D cell are marked near the battery contacts. The 9-volt battery is
held in place with a spring clip, but contact is made with a separate connector that
is polarized. Always observe correct polarity when replacing the 1.5-volt D cell.

7

1.4 Printed Circuit

Most of the component parts are mounted on a printed circuit board which simpli­fies assembly and maintenance, thus extending the useful life of the Instrument.

1.5 Case

The case has an externally accessible battery and fuse compartment. Access to
the batteries and 1 amp fuse is obtained by unscrewing a single screw on the
back of the case and sliding out the compartment cover.

1.6 Adjust-A-Vue Handle

A carrying handle is attached to the Instrument case. The handle may be used to
support the Instrument in a convenient sloping position for easy viewing. The
case can also be placed in either a vertical or horizontal position. The horizontal
position is preferable for greater accuracy since the Instrument is calibrated in
this position.

1.7 Test Leads

Each Instrument is furnished with one pair (Catalog No. 00125) of probe type test
leads (one red and one black, each 48 inches long) for all applications of the
Instrument. These test leads ha ve elbo w prods on one end to connect the leads to
the recessed jacks on the Instrument front panel. The probe tips at the opposite
end have threaded shoulders to accept the screw-on insulated alligator clips
(furnished with the test leads) or the 5000 volt test probe(s) to extend the
Instrument’s AC or DC voltage range. The test leads and the insulated alligator
clips are rated for the voltage and current ranges available on the 260. Maximum
ratings are 1000V AC or DC or 10 DC amps. Do not exceed these ratings for the
test leads in any application.

1.8 Technical Data

1 . DC VOLTS:

Ranges: 0-1-2.5-10-25-50-250-500-1000V
Sensitivity: 20,000V per Volt

2. DC MILLIVOLTS:
Range: 0-250mV
Sensitivity: 20,000 per Volt

3 . AC V OLTS:

Ranges: 0-2.5-10-25-50-250-500-1000V
Sensitivity: 5,000V per Volt

4 . OUTPUT VOLT AGE

(AC):
Ranges: 0-2.5-10-25-50-250 (limited to 350V DC)

5. DC MICROAMPERES:
Range: 0-50µA
Voltage Drop: 250mV

Table 1-1. Technical Data

8

6. DC MILLIAMPERES:
Ranges: 0-1-10-100-500 mA
Voltage Drop
(Approx.): 250 mV, 255 mV, 300 mV, 500 mV

7. DC AMPERES:
Range: 0-10A
Voltage Drop
(Approx.): 255 mV

NOTE: The 10A range is not internally fused.

8.

9. *ACCURACY:
DC Voltage Ranges: 2% of Full Scale
DC Current:
0-50 µA Range: 1.5% of Full Scale
Other Ranges: 2% of Full Scale
**AC Voltage Ranges: 3% of Full Scale
Frequency Response: Referenced to 100 Hz (Figures 4-4 and 4-8)
Resistance Ranges:
R X 1: 2.5° of Arc
R X 100: 2° of Arc
R X 10,000: 2° of Arc

10 DECIBELS:

Range: -20 to +10 dB, -8 to +22 dB, 0 to +30 dB,
Reference Level: With zero dB power level equal to 1 mW

11. BATTERIES:
Voltage: 1.5V, 9V
NEDA No.: 13F, 1604A

12. FUSE: F1 1A, 250V , type 3AG, quic k-acting Littlefuse Type

ecnatsiseR1XR001XR0001XR

egnaR0002-0  000,002-0  M02-0 

retneC

gnidaeR

21  0021  000,021 

nepOlanimoN
egatloVtiucriCV5.1V5.1V9

trohSlanimoN

tnerruCtiucriCAm521Am52.1Aµ57

+6 to +36 dB, +20 to +50 dB
across a 600V line.

312001, F2 2A, 600V Littlefuse Type BLS or 2A
600V, BussmanType BBS.

13. TEST LEADS: 1 red, 1 black, 48" long.

14. SIZE: 5 1/4” x 7" x 3 1/8" (13.34 x 17.78 x 7.94 cm)

9

15. WEIGHT: 2 1/2 lbs. (0.9331 kg)

16. ***RATED-CIRCUIT­TO-GROUND V OLT AGE: 1000 V AC/DC Max.

* Accuracies specified are for the 260 in a horizontal position.
** Responds to the average value of an AC current, and is calibrated to indicate
the RMS value of a pure sine wave.
*** Per ANSI C39.5 April 1974: The specified voltage with respect to ground,
which may be safely and continuously applied to the circuit of an Instrument.

1.9 Definition of Accuracy

The voltage and current accuracy of this Instrument is commonly expressed as a
percent of full scale. This should not be confused with accuracy of reading (indi­cation). For example, +2% of full scale on the 10V range allows an error of ±0.20V
at any point on the dial. This means that at full scale, the accuracy reading would
be ±2%, but at half scale it would be ± 4%. Theref ore , it is adv antageous to select
a range which gives the closest indication to full scale.

1.10 Safety Considerations

This Operator’s Manual contains cautions and warnings alerting the user to haz­ardous operating and service conditions. This information is flagged by CA UTION
or WARNING symbols where applicable, throughout this publication, and is de­fined on the inside front cover of this manual under Notes and Safety Information.
Adhere to these instruction in order to ensure the safety of operating and servic­ing personnel and to retain the operating conditions of the Instrument.

1.11 Audio Alarm

The 260 Audio Alarm transducer will emit an audio sound when the continuity of
a circuit being tested is completed.

!

No circuit continuity tests are to be made with electrical power “ON.” Turn “OFF”
all electrical power.

1.12 Accessories

Table 1-2. Items and Accessories Furnished with this Instrument

Quantity Description Number

1 Test Lead Set - one red and one black (48” long) 00125

each with combination probe tip and removable

rubber-sleeved alligator clip.
*1 1.5 Volt, D Cell, NEDA 13F
*1 9.0 Volt Cell, NEDA 1604A

2 1 Amp, 250V Fuse, Littlefuse Type #312001
1 2A, 600V Fuse, Littlefuse Type BLS (or Bussman

Type BBS)

1 Operator’s Manual 6-115021

* Batteries are standard items replaceable at local retail stores.

10

1.13 Additional Accessories

Table 1-3. Additional Accessories

Description Catalog No.

Deluxe Case ............................................................................................. 00812

Vinyl Sheath Case ....................................................................................01818

Leatherette Ever-Redy Hard Case, Drop Front ...................................... 00805

5,000 Volt AC Probe 5 k/V .....................................................................00794

5,000 Volt DC Probe 20 k/V ...................................................................00795

10,000 Volt AC Probe 5 k/V ...................................................................00036

10,000 Volt DC Probe 20 k/V .................................................................00034

Model 150-2 Amp-Clamp ......................................................................... 00541

Model 151-2 Line Splitter......................................................................... 00544

!

High voltage probes and test prod adapters provide a convenient and economi­cal means of extending the voltage range of the 260. They are intended for high
voltage measurements in low power, consumer type products such as TV receiv­ers, oscilloscopes, burner ignition systems, etc. They are NOT intended for and
should NOT be used for measurements in high power circuitry such as power
substations or distribution centers, RF induction heaters or broadcast transmit­ters, x-ray equipment or other applications where an operator error may create a
dangerous condition.

1.13.1 Accessory DC High Voltage Probes

The DC high voltage probes are designed for use with the Simpson 260 or any
20,000 ohms per volt VOM having a 2.5 volt DC range and scale graduations
from 0-10 or multiple thereof for the 10 kV probe.
Accuracy: Probe Resistance 2%. DC high voltage test probes are available at
local electronic parts distributors.

1.13.2 Accessory AC High Voltage Probe

The 10,000 volts AC accessory probe is similar to the high voltage DC probes
with the following exceptions: The AC high voltage probe is designed to extend
the 260-8 AC voltage range . The probe can be used with the Simpson 260, 10 volt
AC range.

NOTE: Instructions are furnished with each high voltage probe.

1.13.3 Amp-Clamp Model 150-2

The Simpson Amp-Clamp Model 150-2 allows AC current measurements with­out breaking the circuit under test. The Amp-Clamp works as a transformer con­taining a split core for accommodating the conductor which carries the current
being measured. The current-carr ying conductor becomes the transformer pri­mary and a coil in the Amp-Clamp serves as the secondary winding. The Amp­Clamp output voltage is proportional to the current measured and can be applied
to the 260 as an AC voltage.

The Amp-Clamp has a range selector with 6 positions. Any of the following cur­rent ranges can be used with the 260: 5, 10, 25, 50, 100 or 250 amperes.

NOTE: Instructions are furnished with each Amp-Clamp.

11

2. INSTALLATION

This section contains information and instructions for the installation and ship­ping of the Instrument. Included are unpacking and inspection procedures, war­ranty, shipping, power source requirements and operating position.

2.1 Unpacking and Inspection

Examine the shipping carton for signs of damage. If damaged, notify the carrier
and supplier and do not attempt to use the Instrument. If the Instrument appears
to be in good condition, read Operator’s Manual in its entirety. Become familiar
with the Instrument as instructed in the manual, then check the electrical perfor­mance as soon as possible. Check that all items are included with the Instrument
(Refer to Table 1-2).

A 1.5V battery and a 9V battery may be found in separate envelopes in the box
with the Instrument and the test leads. Two alligator clips for the test leads are in
a polyethylene bag. (See Section 5 for instructions on how to install the batteries.

2.2 Warranty

The Simpson Electric Company warranty policy is printed on the inside front
cover of this manual. Read carefully before requesting warranty repairs.
For all assistance, contact the nearest Authorized Service Center or the factory
directly. Give full details of any installation difficulties and include the Instrument
model number, series number, and date of purchase. Service data or shipping
instructions will be mailed promptly. If an estimate of charges for non-warranty or
other service work is required, a maximum charge estimate will be quoted. This
charge will not be exceeded without prior approval.

)

2.3 Shipping

Pack the Instrument carefully and ship it, prepaid and insured, to the proper
destination.

2.4 Power Source Requirements

There are two batteries in the ohmmeter circuits: One is a NEDA 13F D size cell
that furnishes 1.5 volts for the R X 1 and R X 100 ranges. A NEDA 1604A battery
furnishes 9 volts for the R X 10,000 range. The 1.5 v olt D cell is held in place with
two spring clips which also serve as battery contacts. The 9-volt battery is held in
place with a spring clip but contact is made with a separate connector that is
polarized. (Always observe correct polarity when replacing the 1.5-volt D cell.)

2.5 Operating Position

A handle is attached to the side of the Instrument case. The handle may be used
to support the Instrument in a convenient, sloping position for easy viewing. The
VOM case can also be placed either in a vertical or hor izontal position. The
horizontal position is preferable for greater accuracy since the Instrument is cali­brated in this position.

12

3. CONTROLS, JACKS AND INDICATORS

3.1 Front Panel Description

All operating and adjustment controls, jacks, and indicators for the Instrument are
illustrated in this section along with a list (Table 3-1) describing their function.
Become familiar with each item before operating the Instrument.

Table 3-1. Controls, Jacks and Indicators

1. Front Panel: The 260 is a large, easy-to-read 4-1/2” indicating Instru­ment. Below the Instrument are three controls and seven
circuit jacks. Switch positions and circuit jacks are marked
in black characters for easy reading.

2. Range Switch: This switch is used to select one of the twelve range

positions.

Figure 3-1. Front Panel Controls, Jacks and Indicators

3. Function Switch: The function switch has four position: *(Audio), +DC, -DC,
and AC Volts Only. To measure DC current or voltage, set
the function switch at the -DC or +DC position, depending
on the polarity of the signal applied across the test leads.
To measure AC voltage, set the function switch to the AC
position. For resistance measurement, the switch may be
set in either the +DC or -DC position. The polarity of the
internal ohmmeter battery voltage will be as marked at the
jacks when the switch is in the +DC position and reversed
in the -DC position. To chec k circuit continuity set the func­tion switch to the “* ” position.

13

4. Zero Ohms: This control is used to compensate for variations in the
voltage of the internal batteries when making resistance
measurements.

5. Circuit Jacks: There are seven jacks on the front panel marked with the

functions they represent (Figure 3-1). These jacks provide
the electrical connections to the test leads. The COMMON
(-) jack is used (in conjunction with the black test lead) as
the reference point for the measurement of all the func­tions with the exception of the 10A range.

6. Pointer Adjust

For Zero: With the Volt-Ohm-Milliammeter in an operating position,

check that the pointer indicates zero at the left end of the
scale when there is no input. If pointer is off zero, adjust the
screw located in the cover below the center of the dial. Use
a small screwdriver to turn the screw slowly clockwise or
counterclockwise until the pointer is exactly over the zero
mark at the left end of the scale. With the indicating pointer
set on the zero mark, reverse the direction of the rotation of
the zero adjuster slightly to introduce mechanical freedom
or “play”, but not enough to disturb the position of the indi­cating pointer. This procedure will avoid disturbances to
the zero setting by subsequent changes in temperature,
humidity, vibration, and other environmental conditions.

4. OPERATION

This section of the manual contains information required to use and operate the
Instrument in a safe and proper manner.

!

Multifunction instruments (VOM’s) such as the 260-8 are intended as general
purpose measuring Instruments for use in low power circuitry such as found in
consumer appliances, TV and radio receivers, and in general laboratory applica­tions. Their use is not recommended in high voltage, high power circuitry where
operator errors and inadequate personal protective measures could result in
serious injury from arcing or explosion. Such circuitry is found in industrial or
commercial applications such as induction (r-f) heaters and broadcast transmit­ters, power substations and distribution centers, x-ray equipment, large motor
controls, etc. Working in the high voltage section of such equipment requires
single-function, often specially designed instruments used by specially trained
personnel using appropriate protective equipment and procedures.

4.2 Safety Precautions

The following precautions are suggestions and reminders of commonly recog­nized safe practices as well aspecific hazards to be avoided and are not implied
to be sufficient enough to ensure the safety of untrained personnel in all circum­stances. Neither is this manual a substitute for technical manuals covering the
equipment being measured. Always refer to the equipment manual and its spe-

14

cific warnings and instructions and observe them as well as those contained
herein.

a. The Instrument should only be used by personnel qualified to recognize

shock hazards and who are trained in the safety precautions required to
avoid possible injury.

b. Do not connect any terminal of this Instrument to a circuit point at which a

voltage exceeding 1000V AC or DC may exist with respect to earth ground.
(Refer to Table 1-1, item 16.)

c. Turn off power and discharge all capacitors in the circuit to be measured

before connecting to or disconnecting from it.

d . Before using this Instrument, check accessories (if any) and check test leads

for missing, damaged, deteriorated or otherwise faulty insulating parts. Do
not use, or permit the use of, equipment with faulty insulation until it has been

properly repaired.
e. Always wear safety glasses when working in electrical circuitry.
f. Do not work alone on high voltage circuits. Make certain that someone ca-

pable of giving aid is watching nearby.
g . Do not handle the Instrument, its test leads, or the circuitry while high voltage

is being applied.
h. Hands, shoes, floor, and workbench must be dry. Avoid making measure-

ments under humid, damp, or other environmental conditions that could

effect the dielectric withstanding voltage of the test leads or the Instrument.
i. Do not change switch settings or test lead connections while the circuit is

energized. A mistake could damage the Instrument and cause personal in-

jury.
j. Locate all voltage sources and accessible current paths before making con-

nections to circuitry.

!

Dangerously high voltages may appear unexpectedly or in unexpected locations
in faulty equipment. An open b leeder resistor , f or example, may result in a capaci­tor retaining a dangerous charge.

k. Make certain that the equipment being worked on is properly grounded and

fuses are of the proper type and rating.
l. Double-check switch positions and jack connections before applying power

to the Instrument.
m. Remain alert for low voltage circuits which may be floating at high voltage

with respect to earth ground and for composite voltages (AC + DC) as found

in r-f amplifiers. The floating voltage or composite voltage must not exceed

the Instrument’s rated maximum circuit-to-ground voltage.
n. Do not make electrical measurements where the air may contain explosive

concentrations of gas or dust, such as in mines, grain elevators, gasoline

stations or in the presence of charging batteries until determined to be safe

by qualified personnel. Note that even metallic dusts can be explosive.
o. No General Purpose VOM is to be used to make electrical measurements

on blasting circuits or blasting caps.

15

4.3 Polarity Reversing

The function switch provides a convenient means to reverse polarity of the inter­nal battery to facilitate testing semiconductor devices. The +DC and -DC posi­tions transpose internal connections to the COMMON and +jacks and therefore
can also be used to reverse polarity of external voltages and currents connected
to these jacks (only). Because polarity reversing momentarily interrupts the cir­cuit, it should not be done while measuring current or voltage without first turning
off the circuit power. When making measurements on the 50µA/250mV or 10A
range, polarity can be corrected only by reversing the test leads.

4.4 Measurement of Unknown Voltage or Current

Sometimes the approximate voltage or current to be measured is known and the
correct range may easily be selected. Often however, particularly when working
upon faulty equipment, the voltage or current is unknown or may be much higher
than normal or anticipated. When working upon unfamiliar or unknown equip­ment, always begin a measurement using the highest range available on the
Instrument. Once it is determined that the voltage is within the limits of a lower
range, change to the lower range.

4.5 Test Leads

These are provided with accessory screw-on alligator clips which may be at­tached to the probe tips. As well as eliminating the need to hand-hold test prods
to a circuit for extended periods, the test clips reduce hand proximity to a high
voltage circuit while energized. Circuit power must be turned off and any charged
capacitors discharged before connecting or disconnecting clips to or from the
current.

4.6 DC V oltage Measurement

!

Before measuring voltage, review the SAFETY PRECAUTIONS listed in para­graph 4.2. Also, when using the 260 as a millivoltmeter, care must be taken to
prevent damage to the indication instrument from excessive voltage. Before us­ing the 250 millivolt range, use the 2.5V DC range to determine that the voltage
measured is not greater than 250mV (or .25V DC).

4.6.1 DC Voltage Measurement 0-250 mV Range

a. Set the function switch at +DC (Figure 4-1).
b. Plug the black test lead in the -COMMON jack and the red test lead into the

+50 µAmps/250mV/10A jack.
c. Set the range switch at 50 µAmps (COMMON) position with 50V.
d. Connect the black test lead to the negative side of the circuit being measured

and the red test lead to the positive side of the circuit.
e. Read the voltage on the black scale marked DC and use the figures marked

0-250. Read directly in millivolts.
NOTE: For polarity reversing see paragraph 4.3

16

4.6.2 DC Voltage Measurement 0-2.5 Through 0.250V Range

a. Set the function switch at +DC (Figure 4-1).
b. Plug the black test lead into the -COMMON jack and the red test lead into the

+jack.
c. Set the range switch at one of the five voltage range positions marked 2.5V,

10V , 25V, 50V, or 250V .

When in doubt as to the highest voltage present, always use the highest

voltage range as a protection to the Instrument. If the voltage is within a

lower range, the switch may be set for the lower range to obtain a more

accurate reading. Be sure power is off in the circuit being measured and all

capacitors discharged.
d. Connect the black test lead to the

negative side of the circuit being

measured and the red test lead to

the positive side of the circuit.
e. Turn on the power in the circuit be-

ing measured.
f. Read the voltage on the black scale

marked DC. For the 2.5V range, use

the 0-250 figures and divide by 100.

For the 10V, 50V , and 250V r anges,

read the figures directly . For the 25V

range, use the 0-250 figures and

divide by 10.
g. Turn off power to the circuit and wait

until the meter indicates zero be-

fore disconnecting the test leads.

Figure 4-1. Jacks and Switch Positions for
Measuring DC Voltages, 0-250V Ranges

4.6.3 DC Voltage Measurement 0-500V Range

!

Use extreme care when working with high voltage circuits. Do not touch the
Instrument or test leads while power is on in the circuit being measured. Before
proceeding with the following steps, review the Safety Precautions in Paragraph

4.2.
a. Set the function switch at +DC (Figure 4-2).

b. Set the range switch at the 250V/500V/1000V position.
c. Plug the black test lead into the -COMMON jack and the red test lead into the

500V jack
d. Be sure power is off in the circuit being measured and all capacitors dis-

charged. Connect the black test lead to the negative side of the circuit being

measured and the red test lead to the positive side of the circuit.

17

e. Turn on power in circuit being

measured.
f. Read the voltage using the 0-50

figures on the black scale marked

DC. Multiply the reading by 10.
g. Turn off power to the circuit and

wait until the meter indicates zero

before disconnecting the test

leads.

Figure 4-2. Jacks and Switch Positions
for Measuring DC Voltage, 0-250
Ranges

4.6.4 DC Voltage Measurement 0-1000V Range

!

Use extreme care when working with high voltage circuits. Do not touch the
Instrument or test leads while power is on in the circuit being measured. Before
proceeding with the following steps, review the Safety Precautions in Paragraph

4.2.
a. Set the function switch at +DC

(Figure 4-3).
b. Set the range switch at the

250V/500V/1000V position.
c. Plug the black test lead into the

-COMMON jack and the red test

lead into the 1000V jack.
d. Be sure power is off in the cir-

cuit being measured and all ca-

pacitors discharged. Connect

the black test lead to the nega-

tive side of the circuit being

measured and the red test lead

to the positive side of the circuit.
e. Turn on power in circuit being

measured.
f. Read the voltage using the 0-

10 figures on the black scale

marked DC. Multiply the read-

ing by 100.
g. Turn off power to the circuit and

wait until the meter indicates zero

before disconnecting the test

leads.

Figure 4-3. Jacks and Switch Positions
for Measuring DC Voltage, 1000V
Range

18

4.7 AC Voltage Measurement

!

Branch and distribution circuits
(120/240/480V etc.) can de­liver dangerous explosive
power momentarily into a short
circuit before the fuse/breaker
opens the circuit. Make certain
that the instrument switches are
set properly, jacks are con­nected properly, and that the
circuit power is turned off be­fore making connections to
such circuits. (Refer to Para­graph 4.7-d.)
The 260 responds to the aver­age value of an AC waveform.
It is calibrated in terms of the

PERCENT RELATIVE ERROR

+5
+4

+3

+2

+1

0

-1

-2

-3

-4

-5

AC VOLTAGE RANGES

2.5 VAC RANGE
10VAC RANGE

50 VAC RANGE
250 VAC RANGE
500 VAC RANGE

1000 VAC RANGE

RMS value of a pure sine wave. If
the waveform is nonsinusoidal and
depending

on its waveform, the
reading may be either higher or
lower than the true RMS value

10Hz

100Hz 1KHz 10KHz

FREQUENCY

100KHz

Figure 4-4. Frequency Response, AC
Voltage ranges

of the measured voltage. Therefore an error may occur if the 260 is used to
measure a nonsinusoidal waveform. Also, accuracy is lessened at higher input
frequencies. (Figure 4-4.)
Before proceeding with the following steps, review the Safety Precautions in
Paragraph 4.2.

4.7.1 AC Voltage Measurement 0-2.5 Through 0-250V Range

a. Set the function switch at AC

Volts Only position.

NOTE: The meter will not indicate if

the switch is incorrectly set to a
DC position.

b. Set the range switch at one of

the five voltage range positions
marked 2.5V, 10V, 25V, 50V or
250V. (When in doubt as to ac­tual voltage present, always use
the highest voltage range as a
protection to the Instrument. If
the voltage is within a lower
range, the switch may be set for

1MHz

Figure 4-5. Jacks and Switch
positions for measuring AC
Voltages, 0-2.5 through 0-250V
Ranges

19

the lower range to obtain a more accurate reading.)

c. Plug the black test lead into the -COMMON jack and the red test lead into the

+jack.
d. Turn off power to the circuit being measured and discharge all capacitors.
e. Connect the test leads across the circuit voltage to be measured with the

black lead to the grounded side.
f. For the 2.5V range read the value directly on the scale marked 2.5 VAC. For

the 10V, 25V, 50V and 250V ranges, read the red scale marked AC and use

the black figure immediately above the scale.

4.7.2 AC Voltage Measurement 0-500V Range

!

Do not attempt any voltage measurement which may exceed 1000 volts or the
circuit-to-ground voltage of the instrument, 1000 volts maximum.
Be sure that the range switch is set to the 250V/500V/1000V range, function
switch to AC Volts Only position, and the test leads connected to COMMON and
500V jack.
Do not touch the Instrument or test leads while the power is on the circuit being
measured.
Use extreme care when working in high voltage circuits. Do not handle the Instru­ment or test leads while the circuit being measured is energized. Review all
Safety Precautions in paragraph 4.2 and in the instruction manual for equipment
being tested.

a. Set the function switch at AC

Volts Only position.

!

When making AC voltage measure­ments with the function switch incorrectly
set to DC, the Instrument pointer will re­main at or near zero, indicating a false
“no voltage present” condition that could
be hazardous.

b. Set the range switch at 250V/500V/

1000V position.
c. Plug the black test lead into the -

COMMON jack and the red test

lead into the 500V jack.
d Be sure the power is off in the cir-

cuit being measured and that all

capacitors have been discharged.
e. Connect the test leads across the

circuit voltage to be measured with
the black lead to the grounded side,
if any.

f. Turn on power in the circuit being

measured.
g. Read the voltage on the red scale marked AC. Use the 0-50 figures and

multiply by 10.

Figure 4-6. Jacks and Switch Positions
for MeasuringACVoltage, 0-500V
Range

20

4.7.3 AC Voltage Measurement 0-1000 Range

!

Use extreme care when working in high voltage circuits. Do not handle the Instru­ment or test leads while the circuit being measured is energized. OBSERVE ALL
SAFETY PRECAUTIONS in paragraph 4.2 and in the instruction manual for the
equipment being tested.
Do not attempt any voltage measure­ment which may exceed 1000V or the
circuit-to-ground voltage of the instru­ment, 1000V max.
Be sure that the range switch is set to
the 250V/500V/1000V range, function
switch to AC Volts Only position, and
test leads connected to COMMON and
1000V jack.
Do not touch the instrument or test leads
while the power is on in the circuit be­ing measured.
a. Set the function switch at AC.
b. Set the range switch at 250V/500V/

1000V position.
c.

Plug the black test led into the

-

COMMON jack and the red test

lead in the 1000V jack.
d. Be sure the power is off in the cir-

cuit being measured and that all

capacitors are discharged.
e. Connect the test leads across the

circuit voltage to be measured with

the black lead to the grounded

side.
f. Turn on the power in the circuit being measured.
g. Read the voltage on the red scale marked AC. Use the 0-10 figures and

multiply by 100.

Figure 4-7. Jacks and Switch Positions
for Measuring AC Voltage, 0-1000V
Range

4.7 Output V oltage Measurement

The following steps instruct how to measure the AC component of an Output
Voltage where both AC and DC voltage levels exist. This occurs primarily in
amplifier circuits. A 0.1 mfd, 400V capacitor in series with the OUTPUT jack
blocks the DC component of the current in the test circuit but allows the AC or
desired component to pass on to the indicating instrument circuit. The blocking
capacitor may alter the AC response at low frequencies but is usually ignored at
audio frequencies (Figure 4-8).

!

Do not connect the OUTPUT jack to a circuit in which the DC voltage component
exceeds 350V.

21

Be

fore proceeding with the following steps, review the Safety Precautions in

Para graph 4.2.

Figure 4-8. Frequency
Response Output Ranges

+10
+8

+6

+4

+2

PERCENT RELATIVE ERROR

25/50 VAC RANGE

0

-2

-4

-6

-8

-10

OUTPUT RANGES

2.5 VAC RANGE
10VAC RANGE

250 VAC RANGE

10Hz 100Hz 1KHz

a. Set the function switch at AC Volts

Only position (Figure 4-9).

b. Plug the black test lead into the -

COMMON jack and the red test lead
into the OUTPUT jack

.

c. Set the range switch at one of the

range positions marked 2.5V, 10V,
25V, 50V, or 250V.

d. Connect the test leads across the

circuit being measured with the
black test lead to the grounded side.

e. T urn on the power in the test circuit.

Read the output voltage on the ap­propriate AC voltage scale. For the
0-2.5V range, read the value di­rectly on the scale marked 2.5 VAC.
For the 10V, 25V, 50V, or 250V
ranges, use the red scale marked
AC and read the black figures im­mediately above the scale.

Figure 4-9. Jacks and Switch
Positions for Output Measurements

4.8 Decibel Measurement (-20 to +50 dB)

10KHz

FREQUENCY

100KHz

1MHz

Certain industries measure in terms of voltage or current ratios (decibels) based
on a specific reference level. The dB scale on the 260 serves this purpose and is
calibrated to a reference level (zero dB) of 0.001W into 600. The scale calibra­tion of -20 to +10 dB is for the 0-2.5V range (zero dB = 0.775V). Higher ranges
may be used by adding an appropriate dB value to the reading in accordance
with the chart below. Before proceeding with the follo wing steps re vie w the Safety
Precautions in Paragraph 4.2

22

a. Refer to Figure 4-10 for switch settings and jack connections
b. Use operating instr uctions for AC VOLTAGE MEASUREMENT, 0-2.5V/10/

25V/50V/250V RANGES (Paragraph 4.10).
NOTE: Do not use the 500V or 1000V ranges for decibel readings.
c. Read decibels on the bottom scale marked dB. For the 10V/25V/50V/250V

ranges, add the appropriate factor from the chart below:

egnaRegatloVegnaRBdgnidaeR

V5.2-001+ot02-yltceriddaer

V01-022+ot8-gnidaerotBd21+dda
V52-003ot0gnidaerotBd02+dda
V05-063+ot6+gnidaerotBd62dda

V052-005+ot02+gnidaerotBd04dda

NOTE: The maximum v oltage ratio that can be measured is +50 dB on the 0-250V
range.
d. If dB measurements are being made to a 0.006W into 500 reference level,

subtract +7 dB from the reading obtained.

Figure 4-10. Jacks and Switch
Positions for Measuring Decibels

4.9 Direct Current Measurement

!

Do not change the range setting of the range or function switches while the circuit
is energized.
Never disconnect test leads from the circuit under measurement while it is energized.
Always turn the power off and discharge all the capacitors before changing the

23

switch settings, or disconnecting the leads.
Never exceed the circuit-to-ground voltage of the instrument (1000V Max,, Table
1-1. Item 16).
Always connect the instrument in series with the ground side of the circuit.

In all direct current measurements, make certain the power to the circuit being
tested has been turned off before connecting and disconnecting test leads or
restoring circuit continuity.

4.9.1 Direct Current Measurement 0-50µA Range

a. Set the functions switch at +DC
b. Plug the black test lead into the -COMMON jack and the red test lead into the

+50µAMPS/250mV jack.
c. Set the range switch at 50µAMPS (dual position with 50V).
d. Open the grounded side of the circuit in which the current is being measured.

Connect the VOM in series with the circuit. Connect the red test lead to the

positive side and the black test lead to the negative side.
e. Read the current on the black DC scale. Use the 0-50 figures to read directly

in microamperes.

NOTE: For polarity reversing see paragraph 4.3.

4.9.2

Direct Current

Measurement 0-1mA through 0­500mA Range

a. Set the function switch at

+DC (Figure 4-11).
b. Plug the black test lead into

the -COMMON jack and the

red test lead into the +jack.
c. Set the range switch at one

of the four range positions

marked 1 mA, 10 mA, 100 mA

or 500 mA.
d. Open the grounded side of

the circuit in which the cur-

rent is being measured. Con-

nect the VOM in series with

the circuit. Connect the red

test lead to the positive side

and the black test lead to the

negative side.
e. Turn the power on. Read the

current in milliamperes on the

black DC scale. For the 1 mA

range, use the 0-10 figures

and divide by 10. For the 10

mA range, use the 0-10 figures directly. For the 100mA range, use the 0-10

figures and multiply by 10. For the 500 mA range, use the 0-50 figures and

multiply by 10.
f. Turn the power off and disconnect the test leads.

Figure 4-11. Jacks and Switch Positions
for Measuring Direct Current

24

!

This range is only intended for measurements in low voltage circuits (under 25V
DC) such as the primary power in vehicles or their accessories.

4.9.3 Direct Current Measurement 0-10A Range

a. Plug the black test lead into the -10A jack and the red test lead into the +10A

jack.
b. Set the range switch at 10 AMPS (dual position with 10 mA).
c. Open the grounded side of the circuit in which the current is being measured.

Connect the VOM series with the circuit, connecting the red test lead to the

positive side and the black test lead to the negative side.
NOTE: The function switch has no effect on polarity for the 10 AMPS range.
d. Turn the power on. Read the current directly on the black DC scale. Use the

0-10 figures to read directly in amperes.
e. Turn the power off and disconnect the test leads.

!

The 10A range is not internally fused in the 260.

When using the 10A range, never disconnect a test lead from a jack or from the
circuit while the circuit is energized. Doing so may damage the test jacks or leads
and the arcing may be hazardous to the operator . Turn off circuit power and wait for
meter reading to drop to zero.

The polarity reversing feature of the function switch does not operate on the 0-10A
range. If polarity is incorrect, turn off circuit power, wait for the meter indicator to
reach zero, and then interchange test lead connections to the circuit.

4.10 Zero Ohms Adjustment

Voltage applied to a resistance range will cause reading errors if low and dam­age to the Instrument if high. When making in-circuit measurements, make cer­tain that the circuit is completely de-energized before making connections to it.

When making in-circuit measurements, circuit paths in parallel with the resis­tance being measured may cause reading errors. Check circuit diagrams for the
presence of such components before assuming that the reading obtained is
correct.

When resistance is measured, the INTERNAL batteries B1 and B2 furnish power
for the circuit. Since batteries are subject to variation in voltage and internal
resistance, the Instrument must be adjusted to zero before measuring a resis­tance, as follows:
a. Turn range switch to desired ohms range.
b. Plug the black test lead into the -COMMON jack and the red test lead into the

+ jack.
c. Connect the ends of test leads together to short the VOM resistance circuit.

25

d. Rotate the ZERO OHMS control until pointer indicates zero ohms. If pointer

cannot be adjusted to zero, one or both of the batteries must be replaced.

(For battery replacement, refer to Section 5.)
e. Disconnect shorted test leads.

4.11 Measuring Resistance

a. Before measuring resistance in a

circuit, make sure the power is off

to the circuit being tested and all

capacitors are discharged. Dis-

connect shunting components

from the circuit before measuring

its resistance.
b. Set the range switch to one of the

resistance range positions (Figure

4-12) as follows:

1. Use R X 1 for resistance read­ings from 0-200.

2. Use R X 100 for resistance
readings from 200 to 20,000.

3. Use R X 10,000 for resistance
readings above 20,000.

c. Set the function switch at either -

DC or +DC position. The results
are the same in either position un­less there are semiconductors in
the circuit. (See paragraph 4.12)
Adjust ZERO OHMS control for
each resistance range.

d. Observe the reading on the OHMS

scale at the top of the dial.

Figure 4-12. Jacks and Switch

Positions for Measuring Resistance

NOTE: The OHMS scale reads from right to left for increasing values of resis­tance.
e. To determine the actual resistance value, multiply the reading by the factor at

the switch position. (K on the OHMS scale equals one thousand.)

4.12 Resistance Measurement of Semiconductors

Make sure that the OHMS range being used will not damage any of the semicon­ductors (refer to table 1-1, item 8).
If there is a “forward” and “backward” resistance such as in diodes, the resistance
should be relatively low in one direction (for forward polarity) and higher in the
opposite direction.
Rotate the function switch between the two DC positions to reverse polarity. This
will determine if there is a difference between the resistance in the two directions.
To check a semiconductor in or out of a circuit (forward and reverse bias resis-

26

tance measurements) consider the following before making measurement:
a. The polarity of the battery voltage will be as marked at the jacks when the

switch is in the +DC position and reversed in the -DC position.

b. Ensure that the range selected will not damage the semiconductor. (Refer to

Table 1-1, item 8, and review the specification limits of the semiconductor
according to the manufacturer’s ratings.)

c. If the semiconductor is a silicon diode or conventional silicon transistor, no

precautions are normally required.

d. If the semiconductor material is germanium, check the ratings of the device

and refer to Table 1-1, Item 8.
NOTE: The resistance of diodes will measure differently from one resistance
range to another on the VOM with the function switch in a given position. For
example, a diode which measures 80 ohms on the R X 1 range may measure
300 ohms on the R X 100 range. The difference in values is a result of the diode
characteristics and is not indicative of any fault in the VOM.

4.13 Continuity Tests

!

Tu rn off all power to the circuit under test before proceeding any further.
a. Set the FUNCTION switch to the

“ * .” Insert the black test lead into

the COMMON (-) and the red test

lead into the (+) jacks, (Figure 4-

13).

b. Touching the test lead probe tips

together should produce sound.
c. To test for continuity, probe the cir-

cuit or component in question. An

audible sound indicates continuity.
d. The higher the circuit’s resistance,

the lower the sound level. The lower

the circuit’s resistance, the higher

the sound level.
e. Refer to paragraph 4.20, Figure 4-

12, for measurements of circuit re-

sistance, if any, that exists.

27

Figure 4-13. Jacks and Switch

Positions for Continuity Tests

5 OPERATOR SERVICING

This Instrument has been carefully designed and constructed with high-quality
components. By providing reasonable care and following the instructions in this
manual, the user can expect a long service life of the Instrument.

!

Prior to opening the battery compar tment cover, disconnect the test leads from
live circuits.

5.1 Battery and Fuse Replacement

1. The batteries and 1 Amp fuse are located inside an isolated compartment at

the top-rear of the Instrument case. Open the compartment as follows:

a. Place the Instrument face down on a soft padded surface.

b. Unscrew the single screw on the cover.

c. Remove the cover from the case and set aside. Batteries and fuse can

now be replaced.
NOTE: If replacement of the 2 AMP high current interrupting fuse is necessary , the
instrument case must be removed (see paragraph 5.3).
Battery replacement is necessary whenever the instrument cannot be adjusted to
infinity (") with open test leads on the Lower Power Ohmmeter ranges or with
shorted test leads on the conventional ohmmeter ranges. If these adjustments
cannot be made, replace the 1.5V, D size cell. If the ohms adjustment cannot be
made on the RX 10K range, replace the 9V battery.

2. Replace the D size cell as follows:

a. Remove the D size cell.
b. Grasp the battery at the center and pull directly up.
c. Insert the new cell, (-) end first while pushing against the (-) terminal

spring clip.

d. Gently push the (+) side of the cell into place.

3. To remove the 9V battery:

a. Remove the battery with the mating connector from the compartment.
b. Take the connector off the old battery and connect it to the new battery.
c. Insert new battery into the compartment.
d. Place the connector leads so they rest between the cavity walls and

clear the fuse terminals. The extended leads are placed between the

battery holder and the top wall of the case.
NOTE: One ampere and two ampere fuse replacement is necessary when there
is no meter deflection on any of the DC, AC Volts or Ohms ranges but the DC
Amps range operates properly.

4. Replace the 1 Amp fuse is as follows:

a. Pull the defective fuse from its retaining spring clips.
b. Snap in the replacement fuse and replace cover.

NOTE: A spare fuse is located in a cavity next to the fuse clip. Use only if proper
replacement is not available; save the internal spare for an emergency.

28

5.2 Fuse Protection

A 1 Amp 250V quick-acting fuse and a 2A high voltage, high interruption capac­ity fuse is connected in series with the input circuit as additional protection to the
VOM against excessive energy fault current, such as a power line overload.

It is important to replace the 1 Amp fuse with a Littlefuse Type 312001 only to
prevent the 2 Amp high interruption capacity fuse from opening on a nominally
high overload.

If the Instrument fails to indicate, the 1 Amp or 2 Amp fuses may be burned out.
(Refer to Paragraph 5.2 for fuse replacement.) A 1 Amp spare fuse is furnished
with each instrument. (Both 1 Amp fuses are located in the battery and fuse
compartment.) The 2 Amp fuse is located on the instrument panel under the
printed circuit board.

5.3 Care

!

a. Do not attempt to clean this instrument with test leads connected to a power

source.

b. Immediately clean all spilled materials from the instrument and wipe dry. If

necessary, moisten a cloth with soap and water to clean plastic surfaces.

c. Do not allow the battery to fully discharge. When the batteries reach the end

of their useful life, they should be replaced promptly. Failure to do so may
result in corrosion at the battery contacts due to battery leakage.

d. Whenever possible, avoid prolonged exposure or usage in areas which are

subject to temperature and humidity extremes, vibration, mechanical shock,
dust, corrosive fumes, or strong electrical or electromagnetic interferences.

e. Monthly care: Verify Instr ument accuracy by performing operational checks

using known, accurate, stable sources. If proper calibration equipment is not
available, contact the nearest Authorized Service Center. (If the Instrument
has not been used for 30 days, check the batteries for leakage and replace
if necessary.)

f. Annual Care: It is recommended that the Instrument be returned annually to

the nearest Authorized Service Center, or the factory, for an overall check,
adjustment, and calibration.

g. Storage: When the Instrument is not in use, store it in a room free from tem-

perature extremes, dust, corrosive fumes, and mechanical vibration or shock.
If storage time is expected to exceed 30 days, remove batteries.

29

6 PARTS LIST AND SCHEMATIC DIAGRAM

This Instrument must be serviced by qualified personnel. To aid in troubleshoot­ing a schematic diagram is shown on page 32. The replacement parts list (Table
6-1) describes the components and refers to Simpson part numbers. Reference
Symbol numbers correlate the components shown on the schematic diagram
with the parts list.

!

Improper or makeshift repairs and/or parts substitutions may be dangerous to the
next user. Replacement parts must have mechanical and electrical characteris­tics identical to the original parts.

The following information is provided as an adjunct to the overall text contained
in this manual and should be read and understood thoroughly before ordering
replacement parts for the instrument.

6.1 Removing the Instrument Case.

To gain access to the inside of the Instrument panel disconnect the test leads and
remove the cover from the battery compartment Remove the four case- fastening
screws. and lift the case from the panel.
When replacing the case, make certain that the wires leading to the battery com­partment are seated in their respective slots within the compartment wall. This will
prevent damage to the wire insulation.

6.2 Replacement Parts and Schematic Diagram

To obtain replacement par ts, address order to the nearest Authorized Service
Center. Refer to paragraph 2.3.1 for ordering instructions.

Table 6-1. Replacement Parts

Reference
Symbol Description Part Number

R1 Rheostat, 150 k 6-111487
R1A Resistor, 20 k 5-119705
R2, R22 Rheostat, 3 k 6-111488
R25 Rheostat, 3 k 6-111488
R2A Resistor, 2.2 k 5-118606
R3 Resistor, .025 6-111575
R4 Resistor, 45 k 1-114192
R5 Resistor, 150 k 1-113366
R6 Resistor, 300 k 5-116808
R7 Resistor, 500 k 1-114090
R8 Resistor, 4 M 1-113362
R9 Resistor, 11.25 M 6-114332
R9A Resistor, 3.75 M 6-114331
R10 Resistor, 3.75M 1-115765
R10A Resistor, 1.25 M 6-114333

30

Reference
Symbol Description Part Number

R11 Resistor, 15 k 1-113347
R12 Resistor, 0.48, 5W (wire wound) 6-114537
R13 Resistor 2, 5W (wire wound) 5-115271
R1 4 Resistor, 22.5V, 3W (wire wound) 5-110194
R1 5 Resistor, 238 1-115897
R16 Resistor, 11, 5W (wire wound) 5-119567
R17 Resistor, 1.095 k 6-111572
R1 8 Resistor, 138 6-111573
R1 9 Resistor, 17.320 k 6-111570
R2 0 Resistor, 113.860 k 6-111571
R21 Potentiometer, 11.25 k 6-111446
R23, R24 Resistor , 4 k 5-114835
R26 Resistor, 7.5 k 1-113370
R27 Resistor, 37.5 k 1-113393
R28 Resistor, 75 k 5-116921
R29 Resistor, 125 k 6-114330
R30 Resistor, 1 M 1-113392
C1 Capacitor, 0.1 µF, 400V 1-113733
D1, D2 Diode, Germanium 1-115970
F1 Fuse, 1A, 250V; 3AG (1-1/4” x 1/4”) 1-112507

Quick acting (Littlefuse Type 312001)

F2 Fuse, 2A, 600V, Littlefuse Type BLS or

2A, 500V, Bussman Type BBS.
For Function Switch 1-115789
Knobs:
For Zero Ohms Adjust 1-115790
For Range Switch 10-864352
Case Assembly, Complete (Including 10-865886
Handle less Battery Compartment Cover)
Battery Compartment
Cover Assembly 10-560357
Cover Assembly for indicating Instrument 10-560288
Probe Tip Leads, 1 red & 1 black 00125
Audio Transducer 6-114337

31

Figure 6-1. Schematic Diagram, Model 260-8XI

32

NOTES:

33

NOTES:

34

NOTES:

35

SIMPSON ELECTRIC COMPANY 853 Dundee Avenue

Elgin, IL 60120-3090 [phone] FAX [phone]

Printed in U.S.A. Part No. 06-115021 Edition 5, 11/01

Visit us on the web at: www.simpsonelectr ic.com

36