Omega Engineering 873C, 873F Owner's Manual

r\: OMEGA

^^ ^^H FiyniiyFFDii\iG iiur

EIMGIIMEERIIMCIIMC.

In 0>lf."f» t lirwup Company

MODEL 873
Hand Held Digital

Thermometer

Operator's Manual

WARRANTY

OI\^EGA warrants this unit to be free of defects in materials and workmanship
and

to

give satisfactory service for a period of

one (1)

year

from

date of purchase.
If the unit sfiould malfunction, it must be returned to ttie factory for evaluation.
Our Customer Service Department will issue

an

Authorized Return (AR) number
immediately upon phone or written request. Upon examination by OMEGA, it
the unit is found to be defective it will be repaired or replaced at no charge.
However, this WARRANTY is VOID if the unit shows evidence of having been
tampered with or shows evidence of being damaged as a result of excessive
current, heat, moisture, vibration, or misuse, (Components which wear or which
are damaged by misuse are not

warranted.

These include contact

points,

fuses,

and triacs.
THERE ARE

NO

WARRANTIES EXCEPT AS STATED

HEREIN.

THERE ARE NO
OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING BUT NOT
LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND OF
FITNESS FOR A PARTICUUR PURPOSE. IN NO EVENT SHALL OMEGA
ENGINEERING, INC. BE LIABLE FOR CONSEQUENTIAL, INCIDENTAL OR
SPECIAL

DAMAGES.

THE BUYER'S

SOLE

REMEDY

FOR

ANY

BREACH OF THIS
AGREEMENT BY OMEGA ENGINEERING, INC. OR ANY BREACH OF ANY
WARRANTY BY OMEGA ENGINEERING, INC. SHALL NOT EXCEED THE
PURCHASE

PRICE PAID BY THE

PURCHASER

TO OMEGA

ENGINEERING,

INC.
FOR THE UNIT OR UNITS OR EOUIPMENT DIRECTLY AFFECTED BY SUCH
BREACH.

Return Requests/Inquiries

Direct all warranty and repair requests/inquiries to OMEGA Customer Service
Department, telephone number

(203)

359-1660.

Before returning any instrument, please
contact the OMEGA Customer Service Department to obtain an authorized return (AR)
numtier. The designated AR number

should

then be marked

on

the outside of

the

return

package.

To avoid processing delays, also please be sure to Include:

1.

Returnee's name, address, and phone number.

2.

Model and Serial numbers.

3. Repair instructions.

i^OMEGA

A. .^H

ENGiniEERING,

IIMC

One Omega Drive, Box 4047

Stamford,

Connecticut 06907-(X)47

[phone] Telex: 996404 Cable: OMEGA

FAX: [phone]

OMEGA'-' is a registered trademark of OMEGA ENGINEERING, INC.

-, Copyright 1984 OMEGA ENGINEERING, INC. Alt rights reserved including

illustrations. Nothing in this manual may be reproduced in any manner, either wholly

or in part for any purpose whatsoever without written permission from
OMEGA ENGINEERING, INC.

Printed in

U.S.A.

M230/025

TABLE OF CONTENTS

GENERAL INFORMATION 1

Unpacking and Inspection 1
Optional Accessories 2
Preparation for Use 3
Safety Symbols

and

Terms 4

Environmental Conditions 4

OPERATION 5

Safety Precautions 6

SERVICING INFORMATION 9

Functionality Check 9
Performance Verification 9
Environmental Conditions 10
Disassembly Instructions 10
Battery Installation/Replacement 12
Calibration 13

Probe Matching 15
Troubleshooting ...: 15
Special Handling of Static Sensitive Devices 18
Component Layout 21
Schematic Diagram 23

GENERAL INFORMATION

The OI^EGA® IVIodels 873C and 873F are Hand Held Digital Thermo­meters. Both instruments have large easy to read liquid crystal displays
(LCD).

The input connection consists of a subminiature, type K thermo­couple, female connector (SMP-K-F). This input accommodates any
OMEGA type K thermocouple probe fitted with an SMP-K-M connec­tor. Cold junction electronic circuitry

in

the 873F/873C automatically
compensates for ambient temperature changes. These instruments
also provide piece-wise linearization conformity for thermocouple non­linearity. The instruments are powered by a 9V battery. Continuous
operation of 350 hours is typical with an alkaline battery or 200 hours
typical with a carbon-zinc battery.

The Model 873C measures temperature from - 55°C to 1000°C on

two ranges. The 200°C range measures temperature from -55.0°C to

199.9°C with a resolution of 0.1°C. The 1000°C range measures
temperature from -55°C to 1000°C with a resolution of 1°C. The ac­curacy is ± (0.25% rdg

-i-

1.0°C)

from -40°C to 1000°C and ± (0.25%

of rdg -l-2°C) for -40°C to -55°C.

The Model 873F measures temperature from - 60°F to 200°F

on

two

ranges. The 200°F range measures temperature from -60.0°F to

199.9°F with a resolution of 0.1°F. The 2000°F range measures
temperature from -60°F to 1999°F with a resolution of 1°F. The ac­curacy of the Model 873°F is ±(0.25% of rdg -i-2.0°F).

UNPACKING AND INSPECTION

Remove the Packing List and verify that all equipment has been
received.

If there are any questions about the shipment, please call

OMEGA Customer Service Department at [phone].
Upon receipt of shipment, inspect the container and equipment for

any signs of damage. Take particular note of any evidence of rough

handling in transit. Immediately report any damage to the shipping
agent.

NOTE

The carrier will not honor any claims unless all shipping
material is saved for their

examination.

After examining and
removing contents, save packing material and carton in the
event reshipment is necessary.

OPTIONAL ACCESSORIES

The following optional accessories can

be

used with the Models 873C
and 873F to enhance the performance of the instrument. These
accessories are available:

Part Number
KS871

SC800
880A2
MN1604
SMP-K-M

SMP-K-F

OT-201-1

Description
Tilt Stand/Belt Clip/Probe Holder; can

be used as a tilt stand or clipped to
your belt. It will hold one compact
probe.

Soft Carrying Case
Deluxe Carrying Case

9V Replacement Battery
Subminiature Thermocouple Connec-

tor, Male
Subminiature Thermocouple Connec-

tor, Female

1 oz jar of High Thermal Conductivity

Paste for fast surface measurements.

PREPARATION FOR USE

The Models 873F and 873C are supplied ready for use with battery
installed.

Connect the appropriate probe to the miniature TC connec-

tor located on the top of the instrument (just above the display).

SAFETY SYMBOLS AND TERMS

The symbol /!\ on the instrument denotes that the user should refer

to the opjerating instructions.
The WARNING used in this manual explains dangers that could result

in personal injury or death.
The CAUTION used in this manual explains hazards that could

damage the instrument.

ENVIRONMENTAL CONDITIONS

Operation of the Models 873C and 873F should take place at

an

am­bient temperature of -10°C to 50°C (14°F to 122°F), less than 80%
relative humidity up to 35°C, lineariy derate 3%

R.H./C

from 35°C to

60°C.

OPERATION

The 873C and 873F Hand Held Digital Thermometers are easy to use
There is only one control (located on the side of the instrument) that
turns the instrument on/off and selects the range. (See Figures 1 and

2).

Use the following procedure to operate the instrument:

1.

Turn on the power to the instrument by selecting the desired range.

Model 873C:
A. 200°C range is the center position of the ON/OFF range switch.
B. 1000°C range is the upper position of the ON/OFF range switch.

Model 873F:

A. 200°F range is the center position of the ON/OFF range switch.

B. 2000°F range is the upper position of the ON/OFF range switch.

2.

Select the appropriate temperature probe and insert it into the input

jack.

3. Make the measurement:
A. Touch the probe tip to the material to be measured.

B. Read the display. The reading is in Celsius for the Model 873C.

The reading is in Fahrenheit for the Model 873F.

NOTE

An open sensor or overrange condition is indicated by:

CAUTION
Do not attempt to measure temperatures beyond
the range of the probe being used. Probe damage
may occur.

WARNING

A shock hazard exists on the Models 8730 and 873F
Input jacks when probes

or

sensors are exposed

to

voltage levels greater than 42V peak to earth ground.

SAFETY PRECAUTIONS

1.

Do not touch the probe tip when measuring excessively high or low

temperature.

2.

Do not exceed 42V peak from the probe tip or input jack to earth

ground.

Miniature TC Connector

Low Battery Indicator

Minus Sign Displayed

•

Plus Sign Implied

3V4 Digit Display—

On/Off Range Switch

OMEGA 873C THERMOMETER

LO

BAT

-loao

200

TYPE K THEHMOCOUPLE

NiCr-N<AI

RANOE:

-IB'C

to

lOOO'C

^ 42V MAX

-^

Figure 1. Model 873C Control Layout

4

Miniature TC Connector

Low Battery Indicator^

Minus Sign Displayed-

Plus Sign Implied

VA Digit Display-

On/Off Range Switch

OMEGA 873F THEHMOMETER

^

r DM I

-\QO.U

^=

TYPE K THEIIMOCOUPI.E

NiCr-NiAl

RANOE.

-tO'E

to

2000*F

A 42V MAX

+

Figure 2. Model 873F Control Layout

SERVICING INFORMATION

This section contains information needed to maintain the Models

873C and 873R The following information is included: functional

check, performance verification, disassembly instructions, battery in-

stallation/replacement, calibration, probe matching, troubleshooting,
parts list, schematic diagram and component layout.

WARNING
The information presented in this section is in­tended for use by qualified personnel only. Turn off
the power and remove all probes from the instru­ment before replacing the battery.

FUNCTIONALITY CHECK

At room temperature hold the tip of a probe sensor between your

thumb and index finger. A reading between 25°C and 40°C (77°F and

104°F) should be observed to confirm functionality of the instrument.

PERFORMANCE VERIFICATION

Accuracy Check

1.

Prepare a distilled water ice bath or use an OMEGA* TRC III Ice

Point Reference Chamber.

2.

Connect a TC probe to the input jack of the instrument.

3. Immerse the TC probe into the TRC III or distilled water ice bath
and allow 10 minutes for thermal stabilization,

4.

Turn on the instrument and use Table 1 to verify that the readings

on each range are within specifications.

Table 1. Performance Verification

Range

200

1000

2000

873°C

0.0 ± 1°C

0 ± 1°C

873°F

32,0 ± 2°F

32 ± 2°F

ENVIRONMENTAL CONDITIONS

The Models 873C and 873F should be at an ambient temperature of

23°C ±1°C and a relative humidity of less than 80%.

DISASSEMBLY INSTRUCTIONS

WARNING
Turn off the instrument and disconnect the
temperature probe before removing the bottom
cover.

NOTE
When disassembling the instrument, handle the PC
board by the edges. Body

oil,

dirt, etc can degrade circuit

performance. Keep the PC board clean and free of

con-

taminants.

1.

Place the unit face down on a bench or other similar surface and

remove the screws from the bottom cover.

2.

Separate the bottom cover from the rest of the instrument by

grasping the top of the case (just above the display) and carefully
lifting it away from the display.

3. Remove the battery.

4.

Remove the standoff (ST-166-1) that secures the PC board to the

case.

The standoff is located in the center of the PC board.

5. Remove the switch cap.

6. Lift the PC board out of the top cover (front panel)

7. Remove the shield.

8. The LCD is held in place on the PC board by a shock resistant
mounting and is assembled as shown in Figure 3.

9. To reassemble the unit, reverse the above procedure.

CAUTION

When removing the

LCD

from the PC board be careful

not to spread the four retaining hooks

on

the clear plastic

bezel out too far. The plastic bezel hooks may fracture.

WARNING

When reassembling the instrument, be sure to

reinstall the switch cover. Common mode voltage
may be present on the switch creating a possible
hazard if the cover Is not installed.

fUa K 7/V RLUSTtn

a HEQUIRED)

BOTTOM COVER

Figure 3. Model 873 Exploded View

BATTERY INSTALLATION/REPLACEMENT

To install or replace the battery:

1.

Remove the bottom cover of the instrument (refer to the

disassembly instructions).

WARNING
Turn the instrument off and disconnect the input
probe before removing the bottom cover. Reinstall
the cover before resuming usa of the instrument.

2.

Remove the old battery.

3. Place the new battery in the battery compartment. Be sure to
observe the proper polarity. Refer to Figure 4.

4.

Reinstall the bottom cover before resuming use of the instrument.

BArrenv

TERMINALS

Rgure 4. Battery Installation

CALIBRATION

Required Test Equipment

1.

DC voltage calibrator wrth

±0.01%

of setting ±20/iV accuracy

2.

100: 1 divider- 1.98k and 20n wirewound resistors, 0.02% ratio

accuracy or better.

3. OMEGA TRC III Ice Point Reference Chamber or distilled water ice
bath.

4.

OMEGA type K TRP Reference Probe or make a thermocouple

Transition junction (see Calibration Set-Up).

Calibration Set-Up

1.

To make a thermocouple transition

junction,

silver solder a piece

of copper wire to each (type

K)

thermocouple wire and insulate the

junction with a waterproof jacket.

2.

Connect the thermocouple wires from the type K transition junc-

tion to an OMEGA Miniature Thermocouple Connector SMP-K-M.

3. Turn on the voltage calibrator.

4.

Plug in the miniature connector (see steps 1 and 2) into the 873

input.

5. Connect the copper wires to the 100:1 divider as shown in Figure

5. Connect the copper/chromel wire to the positive sida

6. Connect the 100:1 divider to the DC voltage calibrator as shown.

7. Use an OMEGA TRC III or prepare the distilled water ice bath as
follows:

A. Drill a hole in the cap of a Dewar flask or Thermos™ to

accommodate the thermocouple,

B. Firmly pack the flask with pea-size ice cubes made from

distilled water and then fill the flask with distilled water.

10

C. Replace the melted ice with more ice while removing the excess

water.

D. Place the cap on the flask. Immerse the thermocouples into the

flask and allow 20 minutes for temperature stabilization.

DC CALIBRATOR

100:1 VOLTAGE DIVIDER

ICE BATH

873

*The

20(1

resistor must be at a uniform temperature during calibration.

Figure 5. Set-Up Procedure

Calibration Procedure

1.

Remove the bottom cover as described in the disassembly instruc-

tions.

WARNING
To prevent a shock hazard, turn the instrument off
and remove the Input probe from the instrument
before removing the bottom cover.

2.

Turn on the Model 873 and perform the calibration adjustments

listed in Table 2 (873C) or Table 3 (873F). For access to calibra­tion adjustments refer to Figure 4.

11

Table 2. Modal 8730 Calibration Adjustments

Step

1
2
3
4

Adjustment

Zero

-i-Gain (xl)
+ Gain(x10)

-Gain

Range
200°C

1000°C

200°C

200°C

Calibrator

Setting

0.00000

+ 41.269mV

-H7.139mV

-1.527mV

Trimmer

Adjust

R112
R115
R104
R105

Desired

Reading

00.0°C
1000°C

175.0°C

-40.0°C

Table 3. Model 873F Calibration Adjustment

Step

1
2
3
4

Adjustment

Zero

-i-Gain(xl)

+ Gain(x10)

-Gain

Range

200°F

2000°F

200°F
200°F

Calibrator

Setting

-0.692mV

-i-44.645mV

3.589mV

-1.929mV

Trimmer

Adjust

R112
R115
R104
R105

Desired

Reading

00.0°F
1990°F

190.0°F

-60.0°F

PROBE MATCHING

To improve the accuracy of the Model 873 while using a particular
proJTe, calibration can be adjusted so that probe errors in the region

of zero (0.0°C or 32°F) are compensated. Place the probe in an ice

bath and allow the reading to stabilize. Then reset the zero adjustment
(R112) to a

0.0°C

or 32°F reading.

TROUBLESHOOTING

The following troubleshooting information is intended to be used by
qualified electronic maintenance personnel who are familiar with the
proper use of standard electronic test equipment.

To gain access to the PC board, refer to the disassembly instructions.

Use the parts list, schematic diagram and component layout to

iden-

tify parts and check point locations.

13

DC Voltage Checks

1.

Battery:

VBAT>7.5V

2.

-HV

to (Analog Ground) = -1-2.9 ±0.3V

3. -fV to (Digital Ground) = +5V ±1V

4.

Reference Diode

CR101 (Anode) to (Analog Ground) = -1.23V ±0.03V.

5. Negative reference divider (R114) referenced to analog ground. *

Pin 12
Pin 10
Pin 11
Pin 7
Pin 9
Pin 8

Pin 6
Pin 4

Pin 5
Pin 3
Pin 2

873C

= -1.23 V
= -0.209V
= -0.209V
= -0.206V
= -0.204V
= -0.204V
= -0.201V
= -0.200V
= -0.197V
= -0.195V
= -0.193V

Pin 12
Pin 11
Pin 10
Pin 9
Pin 8
Pin 7
Pin 6
Pin 5
Pin 4
Pin 3
Pin 2

873F

= -1.23 V
= -0.209V
= -0.208V
= -0.205V
= -0.204V
= -0.203V
= -0.198V
= -0.197V
= -0.196V

= -0.191V

= -0.188V

*The setting of Rl

15

and the tolerances of the resistors within the net-

work (R114) can affect these levels by ±5%.

6. Cold Junction Voltage
(Ambient Temperature = 25°C ±3°C)

Across R102A approximately equal to ImV.

7. Waveform Checks (see Figure 6)

U104 pin 40 (OSC 1)

U104 pin 39 (OSC 2)
U104 pin 38 (OSC 3)
U104 pin 21 (Backplane)

13

U104 PIN 40 (OSC 1)

U104 PIN 39 (OSC 2)

H

25|isec

-^'

K\/

U104 PIN 38

K

= 25/(sec

5V

U104 PIN 21

M

= 20msec

BV

Figure 6. Waveform Checks

14

SPECIAL HANDLING OF STATIC SENSITIVE DEVICES

CMOS devices are designed to function at high impedance levels.
Normal static charge can destroy these devices. Table 4 lists all the
static sensitive devices for the Models 873C and 873F. Steps 1

through 7 provide instructions on how to avoid damaging these

devices.

Table 4. Static Sensitive Devices

Schematic

Designation

U104
U105
U107
U108
U109

1.

Devices should be handled and transported in protective

con-

tainers, antistatic tubes or conductive foam.

2.

Use a properiy grounded work bench and a grounding wriststrap.

3. Handle devices by the body only.

4.

Printed circuit boards must be grounded to bench while inserting

devices.

5. Use antistatic solder removers.

6. Use grounded tip soldering irons.

7. After devices are soldered or inserted into sockets they are pro­tected and normal handling can resume.

15

SPECIFICATIONS

MODEL 873F SPECIFICATIONS

TEMPERATURE SENSOR: Type K INICr-NiAl) Thermocouple,

TEMPERATURE ACCURACY*

RANGE SPAN RESOLUTION IBS to SyP; 2 years)

200°F -60.0° to 199.9° 0.1° ±(0,25% rdg -f-2.0°F)

2000°F -60° to 1999° 1^ ± (0.25% rdg -t- 2°F)

•Includes NBS confofmity,

coW

junction compensation, temperature coefficient

165°

to

82<'FI and

repeatability

errors.

Excludes

therrtiocouple

errors;

however thermocouple

er-

rors around 32°F may be compensated for by an intemal zero adjustment,

REPEATABILITY:

0.3°F

typical for 1 week at constant ambient

temperature.

TEMPERATURE COEFFICIENT: 65° to 82°F; included in accuracy

specification. From 14° to 65° and 82° to 122°F: less than ±(0,025%
of rdg -(-0.2°F)/°F,

INPUT CURRENT: 25nA typical, 50nA maximum.

MODEL 8730 SPECIFICATIONS

TEMPERATURE SENSOR: Type K (Ni&NiAl) Thermocouple,

TEMPERATURE ACCURACY*

RANGE SPAN RESOLUTION (18 to 28°C: 2 yeara)

200°C -40.0° to 199.9° 0.1° ± (0.25% rdg -t-

1.0°C)

-55.0° to -40.0° 0.1° ±(0.25% rdg -t- 2.0°C)

1000°C -40° to 1000° 1° ±(0.25% rdg -I- 1°C)

-55° to -40° If ± (0.25% rdg + 2°C)

"Includes NBS conformity, cold junction compensation, temperature coefficient

(18° to 28°C) and repeatability errors. Excludes thermocouple errors; however tfier­mocouple errors around 0°C may be compensated for by

an

intemal zero adjustment,

REPEATABILrrV:

0.2°C

typical for 1 week at constant ambient

temperature.

TEMPERATURE COEFFICIENT: 18° to 28°C; included in accuracy

specification. From -10° to 18° and 28° to 50°C: less than ±(0.025%
of rdg -(-0.1°C)/°C.

INPUT CURRENT: 25nA typical, 50nA maximum.

Specifications subject to change without notice.

16

MODEL 873F and 873C GENERAL SPECIFICATIONS
(unless specified):

DISPLAY: 314 digit LCD, 13mnfi (0.5") height. Polarity and decimal point

indication.
CONVERSION RATE: 2.5 readings per second.
OVERRANGE AND OPEN SENSOR INDICATION: 3 least significant

digits blanked,
MAXIMUM COMMON MODE VOLTAGE: 42V peak to earth.
NORMAL MODE REJECTION RATIO: Greater than 40dB at 50 & 60Hz.
COMMON MODE REJECTION RATIO: Greater than 120dB at DC, 50 &

60Hz,

ENVIRONMENTAL LIMITS FOR OPERATING (Model 873F): 14° to

122°F,

less than 80% relative humidity up to 95°F; lineariy derate 1.5%

R.H./°F

from 95° to 122°F.

ENVIRONMENTAL LIMITS FOR OPERATING (Model 873C): -10° to

50°C,

less than 80% relative humidity up to 35°C; lineariy derate 3%

R,H./°C

from 35° to 50°C.

ENVIRONMENTAL LIMITS FOR STORAGE (Model 873F): -30° to

140°F,

less than 90% relative humidity up to 95°F; linearly derate 1.5%

R,H,/°F

from 95° to 140°F,

ENVIRONMENTAL LIMITS FOR STORAGE (Model 873C): -35° to

60°C,

less than 90% relative humidity up to 35°C, linearly derate 3%

R.H./°C

from 35° to 60°C.

THERMOCOUPLE LINEARIZATION: Multislope A/D with 11 piecewise

linear segments.
THERMOCOUPLE INPUT: Miniature TC connector.
POWER: 9V alkaline or carbon-zinc (NEDA 1604) battery.
BATTERY LIFE, CONTINUOUS: 350 hours typical with alkaline; 200

hours typical wrth carbon-zinc.
BATTERY INDICATOR: Display indicates "LO BAT" when less than 10%

of life remains.
DIMENSIONS: 160mm long x 69mm vinde x 31mm thick (6,3" x

2.7" X 1.2").

Net weight 210gm (7.5 oz.),
CONSTRUCTION: Heavy duty ABS plastic housing.
ACCESSORIES SUPPLIED: Battery, Instruction Manual and Model

TC-GG-K-24-36-SMP-f\/l Thermocouple Sensor

17

Model 8730 and 873F, Parts List

Sch
Desig.

BT101

C101
C102
C103
0104
C105

C106
0107
0108
0109
0110

OR101

J1001
J1002

J1003
Q101

Q102
Q103

R101

R102*

R102**

R103

R104*
R104**
R105

R106

R107
R108
R109
R110

Rill
R112

R113

Description

9V Alkaline Battery, NEDA 1604

Capacitor,

.^^lf,

50V, Ceramic

Capacitor,

.l/iF,

50V, Ceramic
Capacitor, 33pF, 1000V, Ceramic
Capacitor, .VF, 50V, Ceramic
Capacitor, .IjjF, 50V, Ceramic

Capacitor, 47pF, 500V, Silver Mica or
Ceramic
Capacitor, .33f»F, 63V, Metalized

Polyester

Capacitor, .047^F, 50V, Metalized
Polypropylene
Capacitor,

4.7/JF,

25V, Aluminum

Electrolytic

Capacitor,

.33MF,

63V, Metalized

Polyester
Silicon Diode, 1N914
Miniature TC Connector, Female

Battery Clip
Battery Clip

Transistor, NPN, 2N3904

Transistor, NPN, 2N3904

Transistor, PNP, 2N3906

Resistor, 10k, 5%, 1/4W, Composition

Thick Film Resistor Networic
Thick Rim Resistor Network

Resistor, 10M, 5%, 1/4W, Composition
Potentiometer, Ik

Potentiometer, 50012
Potentiometer, 2k
Thick Film Resistor Network

Resistor, 191k, 1%, 1/8W, Metal Film

Resistor, 390k, 5%, 1/4W, Composition
Thick Film Resistor Network
Factory Selected Resistor (Part of
A31419)
Factory Selected Resistor (Part of
A31410)
Potentiometer, 2k
Factory Selected Resistor (part of

A31419)

Sch

Location

Fl

Bl
C2
82
G1
G1

E2

F2
E2
G5
Dl

E3

A2

Fl
Fl

B2
82
E3

A2

Sev
Sev

Dl
Dl
Dl
D2

Sev

F2
F2

Sev

83
83
83

C3

18

Modei 873C and 873F, Parts Ust (Cont.)

Sch
Desig.

R114*
RIM""
R115
R116
R117
R118

S101
U101

U102
U103

U104
U105
U106
U107
U108
U109

VR101
W101

Description

Thick Film Resistor Network
Thick Film Resistor Networi<
Potentiometer, 2k
Resistor, 100k, 5%, 1/4W, Composition
Resistor, 100k, 5%, 1/4W, Composition
Resistor, 121k, 1%, 1/8W, Metal Film

Switch,

4P3T, On/Off Range Switch

Op Amp, LM308 (Factory selected; part
of A31419)
Current Source, LM334 (Factory selected;
part of A31410)

Low Power JFET Op Amp, TL062Cp
3-1/2 Digit A/D Converter, ICL7136
Quad 2 Input NOR Gate, 4001

Dual Synchronous Up Counter, 4518

12 Stage Binary Counter, 4020
Analog Multiplexer, 4051
Analog Multiplexer, 4053

Reference Diode, 1.23V
Jumper Wire

Sch

Location

Sev
Sev

F4
G4
86
Dl

Sev

C2
03

D2/G5

F2

Sev

05
05
D5

G5

85

•Model 873F

"Model 8730

NOTE:

Mechanical Parts can be found in the expk>ded view (Figure 3).

•

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OiVIEGA^...

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SENSING AND CONTROL

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.AH

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IIMC.

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n Thermocouple Probes and Assemblies
D Industrial Thermocouple Assemblies
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a Wire: Thermocouple, RTD and Thermistor
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designated AR number should then be marked on the outside of the

return package.
To avoid processing delays, also please be sure to include:

1.

Returnee's name, address, and phone number.

2.

Model and Serial numbers.

3. Repair instructions.

jncOMEGA

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.AH

ENGINEERING,

INC.

One Omega Drive, Box 4047

Stamford,

CT 06907-0047

[phone] Telex: 996404 Cable. OMEGA

FAX: [phone]