Ludlum Measurements 3-98 User manual

LUDLUM MODEL 3-98
SURVEY METER
June 2020
Serial No. 346285 and Succeeding
Serial Numbers

LUDLUM MODEL 3-98
SURVEY METER
June 2020
Serial No. 346285 and Succeeding
Serial Numbers

Model 3-98 Survey Meter
June 2020
STATEMENT OF WARRANTY
Ludlum Measurements, Inc. warrants the products covered in this manual to be free
of defects due to workmanship, material, and design for a period of twelve months
from the date of delivery. The calibration of a product is warranted to be within its
specified accuracy limits at the time of shipment. In the event of instrument failure,
notify Ludlum Measurements to determine if repair, recalibration, or replacement is
required.
This warranty excludes the replacement of photomultiplier tubes, G-M and
proportional tubes, and scintillation crystals which are broken due to excessive
physical abuse or used for purposes other than intended.
There are no warranties, express or implied, including without limitation any
implied warranty of merchantability or fitness, which extend beyond the description
of the face there of. If the product does not perform as warranted herein,
purchaser’s sole remedy shall be repair or replacement, at the option of Ludlum
Measurements. In no event will Ludlum Measurements be liable for damages, lost
revenue, lost wages, or any other incidental or consequential damages, arising from
the purchase, use, or inability to use product.
RETURN OF GOODS TO MANUFACTURER
If equipment needs to be returned to Ludlum Measurements, Inc. for repair or calibration, please
send to the address below. All shipments should include documentation containing return shipping
address, customer name, telephone number, description of service requested, and all other necessary
information. Your cooperation will expedite the return of your equipment.
LUDLUM MEASUREMENTS, INC.
ATTN: REPAIR DEPARTMENT
501 OAK STREET
SWEETWATER, TX 79556
800-622-0828 325-235-5494
FAX [phone]

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MODEL 3-98
SURVEY METER
LUDLUM MEASUREMENTS,INC.
SWEETWATER, TEXAS
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M3-97 Survey Meter
page ii
TABLE OF CONTENTS
1.GENERAL.........................................................................................................................................................................1
2.SPECIFICATIONS ..........................................................................................................................................................1
3.DESCRIPTION OF CONTROLS AND FUNCTIONS...............................................................................................2
4.OPERATING PROCEDURES.......................................................................................................................................3
5.CALIBRATION................................................................................................................................................................4
5.1 Detector Operating Point......................................................................................................................................4
5.2 Calibrating CPM Meter Dial................................................................................................................................4
6.MAINTENANCE..............................................................................................................................................................5
7.THEORY OF OPERATION...........................................................................................................................................6
7.1 Input.........................................................................................................................................................................6
7.2 Amplifier..................................................................................................................................................................6
7.3 Discriminator..........................................................................................................................................................6
7.4 Audio........................................................................................................................................................................6
7.5 Digital Analog Convertor......................................................................................................................................6
7.6 Scale Ranging..........................................................................................................................................................6
7.7 Meter Drive.............................................................................................................................................................7
7.8 Meter Compensation..............................................................................................................................................7
7.9 Fast/Slow Time Constant.......................................................................................................................................7
7.10 Low Voltage Supply.............................................................................................................................................7
7.11 Low Voltage Reference........................................................................................................................................7
7.12 High Voltage Supply............................................................................................................................................7
PARTS LIST ........................................................................................................................................................................8
Model 3-97 Survey Meter............................................................................................................................................8
Main Circuit Board, Drawing 464 X 633...........................................................................................................8
Calibration Board, Drawing 363 X 528..............................................................................................................9
Chassis Wiring Diagram, Drawing 363 X 582...................................................................................................9
DRAWINGS AND DIAGRAMS......................................................................................................................................11

Model 3-98 Survey Meter
June 2020
page 1
1. GENERAL
The Model 3-98 is a portable survey instrument
with four linear ranges up to 500,000 cpm. The
instrument features an internal pancake tube
along with the capability of utilizing an
external probe by a switch on the front-panel
labeled INT/EXT. Separate high-voltage
adjustments for the internal and external probes
are provided. The high-voltage power supply is
regulated and adjustable from 200 to 1000 V.
The unit body is made of cast aluminum,
including the meter housing. The can is 0.23
cm (0.090 in.) aluminum. Other operating
features of the instrument include a unimorph
speaker mounted to the instrument can with an
audio ON-OFF capability, fast-slow meter
response, meter reset button, and a six-position
switch for selecting battery check or scale
multiples of X0.1, X1, X10 and X100.
Each range multiplier has its own calibration
potentiometer.
Most Ludlum Measurements GM probes will
operate on this unit, as will many of the
scintillation detectors. The external high
voltage is factory set for 900 V. For special
requirements, it may be adjusted for operation
with any GM or scintillator tube between 400
and 1500 V.
The unit is operated with two "D" cell
flashlight batteries for operation from
approximately 0 to 65 °C (32 to 150 oF). For
temperature operation to -18 °C (0 oF), either
very fresh alkaline or rechargeable NiCd
batteries may be used. Battery drain averages
17 milliamperes.
2. SPECIFICATIONS
RANGES: four linear range multiples of X0.1, X1,
X10, and X100; typically used in combination with
the 0-5k cpm meter dial, 0-5000,000 cpm is
achieved with the range multiplier
METER: 1mA, 6.4 cm (2.5 in.) scale, with pivot-
and-jewel suspension
METER COMPENSATION: temperature
compensation is provided by thermistors on the
main board
INPUT SENSITIVITY: 30 mV, (±10 mV)
HIGH VOLTAGE: adjustable 400-1500 V
RESPONSE: 4 or 22 seconds for 90% of final
meter reading
LINEARITY: ±5% of full scale
INTERNAL DETECTOR: pancake style GM
detector with 1.7 ±0.3 mg/cm2window
WINDOW AREA: Active: 15.51 cm2;
Open: 12.26 cm2
PROTECTIVE SCREEN: stainless steel, 79%
open
POWER: two standard "D" size batteries
BATTERY LIFE: exceeds 600 hours with a fresh
set of alkaline "D" cell batteries
BATTERY DEPENDANCE: instrument
calibration changes less than 3% within battery
check limits on meter
AUDIO: built-in unimorph speaker with an ON-
OFF switch
CONNECTOR: series "C," 706 U/G; BNC or
MHV may also be provided
SIZE: 22.9 x 8.9 x 21.6 cm (9 x 3.5 x 8.5 in.) (H x
W x L), with handle
WEIGHT: 1.4 kg (3 lb), less detector and batteries
FINISH: drawn-and-cast aluminum, with
computer-beige polyurethane enamel and silk-
screened nomenclature

Model 3-98 Survey Meter
June 2020
page 2
3. DESCRIPTION OF CONTROLS AND FUNCTIONS
Range Multiplier Selector Switch: a
six-position switch marked OFF, BAT,
X100, X10, X1, X0.1. Turning the
range selector switch from OFF to BAT
position provides the operator a battery
check of the instrument. A BAT check
scale on the meter provides a visual
means of checking the battery status.
Moving the range selector switch to
one of the range multiplier positions
(X0.1, X1, X10, X100) provides the
operator with typical overall ranges of
0-500 kcpm (for a typical meter dial it’s
0-5 kcpm). Multiply the scale reading
by the multiplier for determining the
actual reading.
AUD ON-OFF Toggle Switch: In the
ON position, the switch energizes the
unimorph speaker, located on the left
side of the instrument. The frequency
of the clicks is relative to the rate of the
incoming pulses. The higher the rate,
the higher the audio frequency. The
audio should be turned OFF when not
required to reduce battery drain.
F-S Toggle Switch: Provides meter
response. Selecting the fast, "F"
position, of the toggle switch provides
90% of the final meter reading in four
seconds. In slow, "S" position, 90% of
the final meter reading takes 22
seconds. In the "F" position, there is a
fast response and large meter deviation.
In the "S" position, there is a slow
response and damped meter deviation.
RESET Pushbutton: When depressed,
provides a rapid means to drive the
meter to zero.
INT/EXT Switch: a two-position
switch used to alternate between the
internal pancake tube and the external
probe. In the INT position, the internal
tube is utilized. In the EXT position,
the external probe is utilized.
H.V. Adjustment: provides a means to
vary the high voltage from 400 to 1500
volts. The high voltage setting may be
checked at the probe connector with an
appropriate voltmeter.
Range Calibration Adjustments:
recessed potentiometers located under
the calibration cover, on the right side
of the front panel. These adjustment
controls allow individual calibration for
each range multiplier.

Model 3-98 Survey Meter
June 2020
page 3
4. OPERATING PROCEDURES
Caution: Verify instrument voltage input
rating before connecting to a power converter.
If the wrong power converter is used, the
instrument and/or power converter could be
damaged.
Note: To open the Battery Lid, twist the lid
button counterclockwise a quarter-turn. To
close, twist clockwise a quarater-turn.
Open the Battery Lid and install two "D"
size batteries. Note (+) (-) marks on the
inside of the lid. Match the battery polarity
to these marks.
Note: The center post of flashlight battery is
positive. Close the battery box lid.
Switch the range switch to BAT. The meter
should deflect to the battery check portion
of the meter scale. If the meter does not
respond, recheck that the batteries have
proper polarity.
Turn the INT/EXT switch to EXT.
Connect a detector to the Model 3-98.
Turn the instrument range switch to X100.
Expose the detector to a check source. The
speaker should click with the AUDIO ON-
OFF switched to ON.
Move the range switch to the lower scales
until a meter reading is indicated. The
toggle switch labeled F-S should have fast
response in "F"and slow response in "S".
Depress the RES switch. The meter should
zero.
Turn the INT/EXT switch to INT and hold
the check source to the end of the can until
a meter reading is indicated.
Note: To assure proper operation of the
instrument between calibrations, an instrument
operational check should be performed prior to
use. A reference reading with a check source
should be obtained at the time of initial
calibration or as soon as possible afterwards,
for confirming correct operation. Confirm the
proper reading on each scale.
If the instrument does not read within 20% of
the proper reading, it should be sent in to a
calibration facility for recalibration.

Model 3-98 Survey Meter
June 2020
page 4
5. CALIBRATION
5.1 Detector Operating Point
CAUTION: The detector operating voltage is
connected to both detectors at all times,
regardless of which position the detector
INT/EXT switch is set. The maximum
operating voltage for the internal GM detector
is 1000 VDC; therefore, the external detector
operating voltage must be kept below 1000
VDC.
Switch the INT/EXT switch to the INT
position and adjust the HVE control for
900 volts at the instrument connector.
NOTE: Measure high voltage with a Model
500 pulser on a high-impedance voltmeter with
a high meg probe. If one of these is not
available, use a voltmeter with a minimum of
1000 megohm input resistance.
For external GM detector applications, the
power supply may be adjusted for 450-550
volt and 900 volt GM tubes. Follow the
above procedure, only set the supply at the
new operating voltage.
For scintillation counters, connect the
scintillator. Expose the unit to a source and
develop an operating voltage versus count-
rate plot. Set the operating voltage at the
flattest portion of this curve.
5.2 Calibration CPM Meter Dial
To calibrate the cpm scale, a Ludlum Model
500 pulse generator is required.
Connect the pulse generator to the
instrument and adjust the pulse
frequency to provide a 4/5-scale
deflection on the X100 range
(400,000 cpm). Adjust the X100
range calibration potentiometer as
required.
Adjust the pulse frequency to a 1/5
scale deflection on the X100 range
(100,000 cpm) and confirm that the
meter indicates ±10% of incoming
pulses. Decrease the pulse
frequency by decades and adjust
each range calibration
potentiometer accordingly.

Model 3-98 Survey Meter
June 2020
page 5
6. MAINTENANCE
Instrument maintenance consists of keeping the
instrument clean and periodically checking the
batteries and the calibration.
An instrument operational check should be
performed prior to each use by exposing both
the internal and external detectors to a known
source and confirming the proper reading on
each scale.
Recalibration should be accomplished after any
maintenance or adjustment of any kind has
been performed on the instrument. Battery
replacements are not considered to be
maintenance and do not normally require the
instrument to be recalibrated.
Ludlum Measurements recommends
recalibration at intervals no greater than one
year. Check the appropriate regulations to
determine required recalibration intervals.
The batteries should be removed and the
battery contacts cleaned of any corrosion at
least every three months. If the instrument has
been exposed to a very dusty or corrosive
atmosphere, more frequent battery servicing
should be used.
Use a spanner wrench to unscrew the battery
contact insulators, exposing the internal
contacts and battery springs. Removing the
handle will facilitate access to these contacts.
Note: Never store the instrument over 30 days
without removing batteries. Although this
instrument will operate at very high ambient
temperatures, battery seal failure can occur at
temperatures as low as 38 °C (100 °F).

Model 3-98 Survey Meter
June 2020
page 6
7. THEORY OF OPERATION
7.1 Input
The external detector pulses are coupled
from the detector through C3 to emitter
follower Q5. R10 and R20 provide bias.
R32 protects Q5 from input shorts. R38
couples the detector to the high-voltage
supply.
The internal detector (V1) pulses are
coupled from the detector through C27 to
emitter follower Q7. R45 limits the current
to V1. R21 and R41 provide bias to Q7.
R40 protects Q7 from input shorts. R39
couples V1 to the high-voltage supply.
The internal detector is used only when the
INT/EXT switch is in the INT position. In
the EXT position, the external detector is
used. When in the EXT position, P1-13 is
grounded, turning off Q6, allowing the
pulses from Q5 to pass on to the amplifier.
P1-14 is opened, allowing R46 to bias Q9,
pulling the pulses from the base of Q7 to
ground and blocking them from the
amplifier. In the INT position, P1-14 is
grounded, turning on Q9, allowing the
pulses from Q7 to pass onto the amplifier.
P1-13 is opened allowing R47 to bias Q6,
pulling the pulses from the base of Q5 to
ground and blocking them from the
amplifier.
7.2 Amplifier
A self-biased amplifier provides gain in
proportion to R33, divided by R6 for the
external detector and R33, divided by R44
for the internal detector. Transistor U9A
provides amplification. U1 is coupled as
current mirror to provide a load for Pin 3 of
U4. The output self biases to 2 Vbe
(approximately 1.4 volts) at Pin 1 of U4.
This provides just enough bias current
through Pin 3 of U4 to conduct all of the
current from the current mirror.
Positive pulses from Pin 7 of U4 are
coupled to the discriminator.
7.3 Discriminator
Comparator U5 provides discrimination.
The discriminator is set by the voltage
divider, R8 and R5, coupled to Pin 3 of U5.
These pulses are coupled to Pin 5 of U6 for
meter drive and Pin 12 of U6 for audio.
7.4 Audio
Discriminator pulses are coupled to
univibrator Pin 12 of U6. Front-panel
audio ON-OFF selector controls the reset at
Pin 13 of U6. When ON, pulses from Pin
10 of U6 turn on oscillator U2, which
drives the can-mounted unimorph. The
speaker tone is set by R13 and C12;
duration by R36 and C23.
7.5 Digital Analog Convertor
Pins 10-15 of U1 are coupled as a current
mirror. For each pulse of current through
R9, an equal current is delivered to C22.
This charge is drained off by R42. The
voltage across C22 is proportional to the
incoming count rate.
7.6 Scale Ranging
Detector pulses from the discriminator are
coupled to univibrator Pin 5 of U6. For
each scale, the pulse width of Pin 6 of U6
is increased by a factor of 10, with the
actual pulse width being controlled by the
front-panel calibration controls and their
related capacitors. This arrangement allows
the same current to be delivered to C22 by
one-tenth of a count on the X.1 range as
100 counts on X1K range.

Model 3-98 Survey Meter
June 2020
page 7
7.7 Meter Drive
The meter is driven by the emitter to Q3,
coupled as a voltage follower in
conjunction with Pin 1 of U3. For the
battery test, the voltage follower is
bypassed, and the meter movement is
directly coupled to the battery through R26.
7.8 Meter Compensation
When the unit is provided with a high-
torque meter movement, with 1.2 V drive,
a temperature compensation circuit is
provided on the main circuit board by way
of components R15, R17, and R23.
7.9 Fast/Slow Time Constant
For the slow time constant, C29 is switched
from the output of the meter drive to
parallel C22.
7.10 Low Voltage Supply
Battery voltage is coupled to U8 and
associated components (a switching
regulator) to provide 5 V at Pin 5 to power
all logic circuits. Unregulated battery
voltage is used to power the meter drive
(Q3) and the high-voltage blocking
oscillator (Q2).
7.11 Low Voltage Reference
U7 provides a 1.22 V precision reference
for HV supply.
7.12 High Voltage Supply
High voltage is developed by blocking
oscillator Q2-T1 and rectified by voltage
multiplier CR1, CR2, CR3, and CR4.
Output voltage increases as current through
Q1 increases, with maximum output
voltage with Q1 saturated.
High voltage is coupled back through R12
to Pin 6 of opamp U3. R2 completes the
high-voltage circuit-to-ground. High-
voltage output is set by R4 (HV Set), which
sets bias of Pin 5 of U3. During stable
operation, the voltage at Pin 6 of U3 will
equal the voltage at Pin 5 of U3. Pin 7 of
U3 will cause conduction of Q1 to increase
or decrease until the high voltage seeks a
level of stability.

Model 3-98 Survey Meter
June 2020
page 8
PARTS LIST
Ref. No. Description Part No.
Model 3-98 Survey Meter
UNIT Completely Assembled Model
3-98 Survey Meter 48-1135
Main Circuit Board, Drawing 363 X 525
BOARD Assembled Circuit Board 5464-633
CAPACITORS
C1 0.0015F, 3kV, C 04-5518
C2 0.01F, 100V, C 04-5523
C3 100pF, 3kV 04-5532
C4 0.0027F, 3kV, C 04-5520
C5 220pF, 100V, C 04-5530
C6-C7 0.0015F, 3kV, C 04-5518
C8 0.001F, 100V, C 04-5519
C9 100F, 10V, DT 04-5576
C10 100pF, 3kV 04-5532
C11 0.0015F, 3kV, C 04-5518
C12 470pF, 100V, C 04-5555
C13 0.01F, 100V, C 04-5523
C14 1F, 35V, DT 04-5575
C15 0.1F, 100V, C 04-5521
C16-C17 100F, 10V, DT 04-5576
C18 330pF, 100V 04-5531
C19 10F, 20V, DT 04-5592
C20 220pF, 100V, C 04-5530
C21 100pF, 100V, C 04-5527
C22 10F, 20V, DT 04-5592
C23 0.01F, 100V, C 04-5523
C24 100F, 10V, DT 04-5576
C25 0.1F, 35V, DT 04-5574
C27 100pF, 3kV, C 04-5532
C29 47F, 16V, DT 04-5550
C30 0.1F, 35V, DT 04-5574
TRANSISTORS
Q1 2N3904G 05-5755
Q2 2N4402BU 05-5763
Q3 2N3904G 05-5755
Q4 2N4402BU 05-5763
Q5-Q7 2N3904G 05-5755
Q8 2N7000 05-5820
INTEGRATED CIRCUITS
U1 CMXT3906TRLF 05-5890
U2 ICM7555 06-6136
U3 TLC27M7IP 06-6248
U4 CMXT3904TRLF 05-5888
Ref. No. Description Part No.
U5 TLC372IP 06-6265
U6 CD4098BE 06-6066
U7 LM385Z-1.2 05-5808
U8 MAX631 06-6249
U9 CMXT3904TRLF 05-5888
U10 CMXT3906TRLF 05-5890
U11 CMXT3904TRLF 05-5888
DIODES
CR1-CR4 1N4007 07-6274
CR5 1N4148 07-6272
RESISTORS
R1-R2 1M, 250mW, 5% 10-7028
R3 10k, 250mW, 5% 10-7016
R4 22k, 250mW, 5% 10-7070
R5 10k, 250mW, 5% 10-7016
R6-R7 4.7k, 250mW, 5% 10-7014
R8 43k, 250mW, 5% 10-7057
R9 33k, 250mW, 5% 10-7019
R10 100k, 250mW, 5% 10-7023
R11 10k, 250mW, 5% 10-7016
R12 1 G, FHV-1, 2% 12-7686
R13 470k, 250mW, 5% 10-7026
R14 10k, 250mW, 5% 10-7016
R16 1k, 250mW, 5% 10-7009
R17 301 OHM, 400mW, 1% 12-7855
R18 47k, 250mW, 5% 10-7020
R19 1k, 250mW, 5% 10-7009
R20-R21 100k, 250mW, 5% 10-7023
R22 10k, 250mW, 5% 10-7016
R24 200 OHM, 250mW, 5% 10-7006
R25 2.2k, 250mW, 5% 10-7012
R26 2.37k, 1/8W, 1% 12-7648
R27 22k, 125mW, 5% 10-7070
R28 100 OHM, 250mW, 5% 10-7004
R29 8.2k, 250mW, 5% 10-7015
R30 100k, 250mW, 5% 10-7023
R31 1k, 1/4W, 5% 10-7009
R32 10k, 250mW, 5% 10-7016
R33 82k, 250mW, 5% 10-7022
R34 10k, 1/4W, 5% 10-7016
R35 100k, 250mW, 5% 10-7023
R36 2.7M, 250mW, 5% 10-7029
R37 1k, 250mW, 5% 10-7009
R38 1M, 333mW, 1% 12-7609
R39 33k, 250mW, 5% 10-7019
R40 10k, 250mW, 5% 10-7016
R41 100k, 250mW, 5% 10-7023
R42 180k, 250mW, 5% 10-7068
R44 4.7k, 250mW, 5% 10-7014

Model 3-98 Survey Meter
June 2020
page 9
Ref. No. Description Part No.
R47 100k, 250mW, 5% 10-7023
R48 10M, 250mW, 5% 10-7031
THERMISTORS
RT15 150 Ohm, 333mW, 2% 07-6332
RT23 150 Ohm, 333mW, 2% 07-6332
INDUCTORS
L1 470UHY 21-9600
TRANSFORMERS
T1 L8050 40-0902
MISCELLANEOUS
W2-W9. RECEPTACLE Cloverleaf
011-6809 18-8771
P1 CONN-1-640456-6
MTA100X16 13-8134
P2 CONN-640456-2 MTA100X2
13-8073
J1 CONTACT#1414 18-9124
J2 JACK-TEST 1128-09-0319
18-8806
Calibration Board, Drawing 363 X 528
BOARD Completely Assembled
Calibration Board 5363-674
CAPACITORS
C1 0.047F 100V C X7R 04-5565
C2 0.0047F 100V C X7R 04-5570
RESISTORS
R1-R2 1 Meg Trimmer 09-6814
R3 100k Trimmer 09-6813
R4 1 Meg Trimmer 09-6814
R5 100k Trimmer 09-6813
R7 100k Trimmer 09-6813
RESISTOR NETWORK
RN1 NETWORK-10k SIP
8PIN 12-7720
MISCELLANEOUS
P3 CONN-640456-5
MTA100 13-8057
P4 CONN-640456-4
MTA100 13-8088
Ref. No. Description Part No.
Chassis Wiring Diagram, Drawing 363 X 582
AUDIO
DS1 UNIMORPH 60690 21-9251
CONNECTOR
J1 CONN-1-640442-6
MTA100 13-8187
J2 CONN-640442-2
MTA100 13-8178
J3 CONN-640442-5
MTA100 13-8140
J4 CONN-640442-4
MTA100 13-8170
J5 RECPT-UG706/U "C" 13-7751
SWITCHES
S1 Centerlab PA600-210 08-6501
S2 55D36-01-2-AJN 08-6514
S3-S4 7101-SYZ-QE 08-6511
S6 30-1 P/B 08-6517
BATTERY
B1-B2 "D" Duracell Battery 21-9313
DETECTOR
V1 GM TUBE-LND7311 01-5008
MISCELLANEOUS
* BATTERY LID W/CE 9363-986
* PORTABLE BATTERY LID WITH
STAINLESS CONTACT 2009-036
* PORTABLE BATTERY NEGATIVE
CONTACT ASSY 2001-065
* PORTABLE BATTERY POSITIVE
CONTACT ASSY 2001-066
M1 PORT BEZEL
FRONT PANEL ASSY 4363-188
* PORT DEEP CAN
ASSEMBLY 4363-615
* MODEL 3-98 CAN ASSY 4363-737
* Model 3-98 CASTING 9363-739
* Model 3-97/3-98 MAIN
HARNESS 8363-700
* PORTABLE KNOB 08-6613

Model 3-98 Survey Meter
June 2020
page 10
Ref. No. Description Part No.
* PROBE KNOB-
MS 91528 08-6606
* PORT BEZEL GLASS
W/O SCREWS 4363-352
* METER MOVEMENT
(1mA) 15-8030
* PORTABLE METER
FACE 7363-136
* HARNESS-PORT
CAN WIRES 8363-462
* PORTABLE BATTERY LID WITH
STAINLESS CONTACT 2009-036
* PORT. LATCH KIT
W/O BATT. LID 4363-349
* PORT. CALIB. COVER
W/SCREWS 9363-200
* PORT. HANDLE
(ROLLED) W/SCREWS 7363-139
* PORT HANDLE FOR CLIP
W/SCREWS 7363-203
* REPLACEMENT CABLE
(STD 39 inch) 40-1004
* CLIP (44-3 TYPE)
W/SCREWS 7002-026-01
* CLIP (44-7 TYPE)
W/SCREWS 7010-007-01
* CLIP (44-6 TYPE)
W/SCREWS 7010-008-01

Model 3-98 Survey Meter
June 2020
page 11
DRAWINGS AND DIAGRAMS
Main Circuit Board, Drawing 464 x 633
Main Circuit Board Component Layout, Drawing 464 x 636 (2 sheets)
Calibration Board, Drawing 363 x 528
Calibration Board Component Layout, 363 x 529 (2 sheets)
Wiring Diagram, Drawing 363 x 582