OHAUS Ranger 3000 Series User manual

SERVICE MANUAL
RANGER
™ 3000 &
RANGER
™ Count 3000 Scales
Ohaus Corporation, 7 Campus Drive, Suite 310, Parsippany, NJ 07054 [phone]

SERVICE MANUAL
RANGER ™ 3000 &
RANGER ™ Count 3000 SCALES
The information contained in this manual is believed to be accurate at the time of publication, but Ohaus
Corporation assumes no liability arising from the use or misuse of this material. Reproduction of this
material is strictly prohibited.
Material in this manual is subject to change.
30072402 © Copyright 2013 Ohaus Corporation, all rights reserved.
TM Registered trademark of Ohaus Corporation.

TABLE OF CONTENTS
Ohaus Corporation www.ohaus.com i Ranger™(Count) 3000 Service Manual
Page No.
CHAPTER 1 GETTING STARTED
1.1 Introduction ..............................................................................................................1-1
1.2 Service Facilities ......................................................................................................1-1
1.3 Tools and Test Equipment Required ........................................................................1-1
1.4 Specifications...........................................................................................................1-2
1.5 Scale Operation Ranger Count 3000 .......................................................................1-3
1.5.1 Overview of the Controls...................................................................................1-3
1.5.2 Power On/Off ....................................................................................................1-4
1.5.3 Menu Setup ......................................................................................................1-5
1.5.4 Menu Navigation...............................................................................................1-5
1.6 Scale Operation Ranger 3000..................................................................................1-6
1.6.1 Overview of the Controls...................................................................................1-6
1.6.2 Power On/Off ....................................................................................................1-6
1.6.3 Menu Setup ......................................................................................................1-8
1.6.4 Menu Navigation...............................................................................................1-8
1.7 Legal For Trade .......................................................................................................1-9
1.7.1 Settings.............................................................................................................1-3
1.7.2 Verification........................................................................................................1-4
1.7.3 Sealing..............................................................................................................1-5
CHAPTER 2 TROUBLESHOOTING
2.1 Troubleshooting .......................................................................................................2-1
2.2 Diagnostic Guide......................................................................................................2-1
2.2.1 Diagnosis..........................................................................................................2-1
2.2.2 Checking Load Cells for Trouble .......................................................................2-2
2.2.3 Testing the Printed Circuit Board (PCB)............................................................2-4
2.2.4 Diagnostic Guide...............................................................................................2-6
CHAPTER 3 MAINTENANCE PROCEDURES
3.1 Preventive Maintenance...........................................................................................3-1
3.1.1 Preventive Maintenance Checklist ....................................................................3-1
3.2 Service Strategy.......................................................................................................3-1
3.3 Opening the Scale....................................................................................................3-1
3.2.1 Separating the Top and Bottom Housings.........................................................3-2
3.4 Removing/Replacing the Main Printed Circuit Board (PCB) .....................................3-3
3.5 Removing/Replacing the Load Cell ..........................................................................3-4
3.6 Setting the Overload Stops ......................................................................................3-5
3.7 Removing/Replacing the Rechargeable Battery .......................................................3-7
3.8 Replacing the Function Label...................................................................................3-7

TABLE OF CONTENTS
Ranger™(Count) 3000 Series Service Manual ii Ohaus Corporation www.ohaus.com
CHAPTER 4 TESTING
4.1. Testing .....................................................................................................................4-1
4.1.1 Test Masses Required ......................................................................................4-1
4.2 Operational Test ......................................................................................................4-1
4.3 Segment Display Test ..............................................................................................4-1
4.4. Performance Tests...................................................................................................4-2
4.4.1 Precision Test ...................................................................................................4-2
4.4.2 Repeatability Test .............................................................................................4-3
4.4.3 Linearity Test ....................................................................................................4-5
4.4.4 Off-Center Load Test ........................................................................................4-5
4.4.5 Adjusting Off Center Load.................................................................................4-6
CHAPTER 5 DRAWINGS AND PARTS LISTS
5-1 Ranger 3000 Scales: Housing & Internal Parts ........................................................5-2
5-2 Ranger Count 3000 Scales: Housing & Internal Parts ..............................................5-4
Appendix A STANDARD CALIBRATION
A.1 Calibration............................................................................................................... A-1
A.2 Setup and Calibration.............................................................................................. A-2
Appendix B SERVICE CALIBRATION
B.1 Service Menu Structure........................................................................................... B-1
B.2 Entering the Service Menu ...................................................................................... B-1
B.3 Capacity Menu ........................................................................................................ B-2
B.4 Graduation Menu .................................................................................................... B-2
B.5 Service Span Calibration......................................................................................... B-2
B.6 Service Linearity Calibration.................................................................................... B-3
B.7 Ramp Menu ............................................................................................................ B-4
B.8 Expand Menu.......................................................................................................... B-4
B.9 End Menu ............................................................................................................... B-4
LIST OF TABLES
TABLE NO. TITLE Page No.
1-1 Specifications ......................................................................................................1-2
1-2 Controls Functions, Ranger Count 3000 ..............................................................1-3
1-3 Battery Charge Status Ranger Count 3000..........................................................1-4
1-4 Ranger Count 3000 Menu Structure ....................................................................1-5
1-5 Control Functions, Ranger 3000 ..........................................................................1-6
1-6 Battery Charge Status, LCD, Ranger 3000 ..........................................................1-7
1-7 Battery Charge Status, LED, Ranger 3000 ..........................................................1-7
1-8 Ranger 3000 Menu Structure...............................................................................1-8
2-1 Load Cell Resistance Readings (in Ohms) ..........................................................2-2
2-2 Color Code for Load Cell Wiring ..........................................................................2-2
2-3 Load Cell Output Readings (in mV with 3.3V Excitation)......................................2-3
2-4 Diagnostic Guide .................................................................................................2-6
3-1 Mounting Bolt Torque Settings.............................................................................3-5
3-2 Overload Stop Gap Settings ................................................................................3-6
4-1 Test Mass Values ................................................................................................4-1
4-2 Repeatability Worksheet......................................................................................4-4
4-3 Linearity Test Masses..........................................................................................4-5

TABLE OF CONTENTS
Ohaus Corporation www.ohaus.com iii Ranger™(Count) 3000 Service Manual
5-1 Ranger 3000 Scales: Housing & Internal Parts ....................................................5-3
5-2 Ranger Count 3000 Scales: Housing & Internal Parts..........................................5-5
LIST OF ILLUSTRATIONS
FIGURE NO. TITLE
1-1. Ranger Count 3000 Front Display with controls ...................................................1-3
1-2. Ranger 3000 Front Display with controls .............................................................1-6
1-3 LFT Lock Switch and Seal ...................................................................................1-9
2-1 Main Printed Curcuit Board..................................................................................2-3
3-1 Screws securing Top Housing .............................................................................3-2
3-2 Top and Bottom Bottom.......................................................................................3-2
3-3 Main Printed Circuit Board ...................................................................................3-3
3-4 Bolts holding Frame to the Load Cell ...................................................................3-4
3-5 Overload stops ....................................................................................................3-5
3-6 Overload Gap positions .......................................................................................3-6
3-7 Rechargeable Battery ..........................................................................................3-7
4-1 Scale drawing of Load Cell and Weighing Pan ....................................................4-6
5-1 Ranger 3000 Scales: Housing & Internal Parts ....................................................5-2
5-2 Ranger Count 3000 Scales:Housing&InternalParts……………………………...5-4

CHAPTER 1 GETTING STARTED
Ranger™(Count) 3000 Series Service Manual 1-1 Ohaus Corporation www.ohaus.com
1.1 INTRODUCTION
This service manual contains the information needed to perform routine maintenance and
service on the Ohaus Ranger 3000 and Ranger Count 3000 Series scales. Familiarity with
thescale’sInstructionManualisassumed.Thecontentsofthismanual are contained in five
chapters:
Chapter 1 Getting Started –Contains information on service facilities, tools and test
equipment, specifications, and the mechanical and electronic functions of the scale.
Chapter 2 Troubleshooting –Contains a diagnostic guide and error code table.
Chapter 3 Maintenance Procedures –Contains preventive maintenance procedures and
disassembly, repair and replacement procedures.
Chapter 4 Testing –Contains a list of required test masses, an operational test, segment
display test, performance tests and adjustments.
Chapter 5 Drawings and Parts Lists –Contains exploded views of Ranger 3000 scales
identifying all serviceable components.
Appendix A Standard Calibration –Explains procedures for Standard Calibration,
performed prior to using a scale, and after service.
Appendix B Service Calibration –Describes the Service Menu and sub-menus, which
allow authorized service personnel to perform factory Linearity and Span calibrations (no
pre-set limits), take Ramp readings, and to set the service menu units.
1.2 SERVICE FACILITIES
To service a scale, the service area should meet the following requirements:
Should be temperature controlled and meet scale specifications for temperature
environmental requirements.
Must be free of vibrations such as fork lift trucks close by, large motors, air currents
or drafts from air conditioning/heating ducts, open windows, people walking by, fans,
etc.
Area must be clean and free of excessive dust.
Work surface must be stable and level.
Scale must not be exposed to direct sunlight or radiating heat sources.
Use an approved Electro-Static Device.
1.3 TOOLS AND TEST EQUIPMENT REQUIRED
The service shop should contain the following equipment:
1. Standard hand tools.
2. Digital Voltmeter (DVM).
3. Standard Electronics tool kit.
4. Grounding mat and clip.
5. Strain Gauge Simulator.

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-2 Ranger™(Count) 3000 Series Service Manual
1.4 SPECIFICATIONS
Complete specifications for the Ohaus Ranger 3000 and Ranger Count 3000 scales are
listed in Table 1-1. When a scale has been serviced, it must meet the specifications listed in
the table. Before servicing the scale, determine what specifications are not met.
TABLE 1-1. SPECIFICATIONS
Model
R31P(E)1502
RC31P1502
R31P(E)3
RC31P3
R31P(E)6
RC31P6
R31P(E)15
RC31P15
R31P(E)30
RC31P30
Capacity
1.5 kg
3 lb
3 kg
6 lb
6 kg
15 lb
15 kg
30 lb
30 kg
60 lb
Min (20e)
0.01kg
0.02kg
0.04kg
0.1kg
0.2kg
0.02lb
0.04lb
0.1lb
0.2lb
0.4lb
Standard readability
d=
0.00005 kg
0.0001 lb
0.0001 kg
0.0002 lb
0.0002 kg
0.0005 lb
0.0005 kg
0.001 lb
0.001 kg
0.002 lb
LFT ON readability
e=10d=
0.0005 kg
0.001 lb
0.001 kg
0.002 lb
0.002 kg
0.005 lb
0.005 kg
0.01 lb
0.01 kg
0.02 lb
Standard
Resolution
1:30000
1:30000
1:30000
1:30000
1:30000
LFT ON
Resolution (nMax)
1:3000
1:3000
1:3000
1:3000
1:3000
Linearity 2d
0.0001 kg
0.0002 kg
0.0005 kg
0.001 kg
0.002 kg
Repeatability 2d
0.0001 kg
0.0002 kg
0.0005 kg
0.001 kg
0.002 kg
Hysteresis 2d
0.0001 kg
0.0002 kg
0.0005 kg
0.001 kg
0.002 kg
Off Center Load 2d
0.0001 kg
0.0002 kg
0.0005 kg
0.001 kg
0.002kg
Creep (60s, 2d)
0.0001 kg
0.0002 kg
0.0005 kg
0.001 kg
0.002 kg
Creep (30 min.
0.5e) MPE
0.0002 kg
0.0005 kg
0.001 kg
0.002 kg
0.005 kg
Stabilization Time
1 sec.
1 sec.
1 sec.
1 sec.
1 sec.
Combined effect
(Increasing /
Decreasing Load)
MPE
MPE
MPE
MPE
MPE
Zero Drift vs.
Temp 2d/C
0.0001 kg / C
0.0002 kg / C
0.0005 kg / C
0.001 kg / C
0.002 kg / C
Span Drift vs. Temp
1d/C,
Less or equal than
MPE
16.7ppm / C
16.7ppm / C
16.7ppm / C
16.7ppm / C
16.7ppm / C
Operating
Conditions
-10C to 40C
-10C to 40C
-10C to 40C
-10C to 40C
-10C to 40C
Storage
Temperature
-40C to 60C
-40C to 60C
-40C to 60C
-40C to 60C
-40C to 60C
Pan Size
225 x 300 mm
225 x 300 mm
225 x 300 mm
225 x 300 mm
225 x 300 mm

CHAPTER 1 GETTING STARTED
Ranger™(Count) 3000 Series Service Manual 1-3 Ohaus Corporation www.ohaus.com
1.5 SCALE OPERATION –RANGER COUNT 3000
This section contains information on the basic operation of the Ranger Count 3000 scale.
1.5.1 OVERVIEW OF THE CONTROLS
Figure 1-1. Ranger Count 3000 Front Display with controls.
TABLE 1-2. Control functions Ranger Count 3000
Button
Primary
Function
(Short
Press1)
ON/ZERO
Turn scale
on.
Zero the
display.
PRINT
Send the
displayed value
to the COM
port.
Target
Initiate the
function of the
current
application
mode.
M+
Accumulate the
weight or pieces.
ID
ID number
input for
library record
edit/recall.
APW
Display/
Store an
APW
Secondary
Function
(Long
Press2)
Off
Turn scale
off.
Units
Change the
weighing unit.
Switch between
Check Weigh,
Check Count
and Off.
Menu
Enter user menu.
View the Audit
Trail event
counters
(extended press)
Menu
Function
(Short
Press)
Yes
Accept the
current
menu or
setting.
No
Advance to the
next menu or
setting.
Increment the
displayed
value.
Back
Go back to the
previous menu
or setting.
Decrement the
displayed
value.
Exit
Exit the menu.
Abort the
calibration in
progress.
Library
Function
(Short
Press)
Yes
Accept the
current
setting.
No
Advance to the
next library or
setting.
Increment the
displayed
value.
Back
Go back to the
previous library
or setting.
Decrement the
displayed
value.
Exit
Exit the library.

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-4 Ranger™(Count) 3000 Series Service Manual
TABLE 1-2. Cont.
Button
Primary Function
(Short Press)
0-9
Enter numeric
values on the
display.
Enter dot (.) on
the display.
C
Clear the last
character from
the display.
Tare
Perform a
tare
operation.
Sample
Display/
Start
new APW
Secondary
Function
(Long Press)
Switch between
scale 1 and
scale 2
(only available if
second platform
is connected)
+/-
Switch
between
positive and
negative value
1.5.2 Power ON/OFF
To turn the scale on, press and hold the On/Zero Off button for 2 seconds. The scale
performs a display test, momentarily displays the software version, and then enters the
active weighing mode.
To turn the scale off, press and hold the On/Zero Off button until OFF is displayed.
The scale can be used on AC power immediately. Allow the battery to charge for 12
hours before using the scale on battery power. The scale will automatically switch to
battery operation if there is a power failure or the power cord is removed. With AC
power, the scale is constantly charging, so the battery charge indicator will remain lit
until fully charged. The scale can be operated during charging, and the battery is
protected against overcharging.
During battery operation, the battery symbol indicates the battery charge level. The scale
will automatically turn off when the batteries are fully discharged.
For maximum operating time, the battery should be charged at room temperature.
TABLE 1-3 Battery Charge Status Ranger Count 3000
Symbol
Charge Level
0 to 10 % Remaining
11 to 40 % Remaining
41 to 70 % Remaining
71 to 100 % Remaining
Notes:
When battery symbol blinks fast, approximately 30 minutes working time is left.
When [lo.bat] is displayed, the scale will shut off.
Charging the scale must be performed in a dry environment.
CAUTION: Battery is to be replaced only by an authorized Ohaus service
dealer. Risk of explosion can occur if the rechargeable battery is replaced
with the wrong type or if it is not properly connected. Dispose of the lead
acid battery according to local laws and regulations.
.

CHAPTER 1 GETTING STARTED
Ranger™(Count) 3000 Series Service Manual 1-5 Ohaus Corporation www.ohaus.com
1.5.3 Menu Setup
Programmable features of the Ranger Count 3000 scales are contained in menus which are
accessed through the Display Panel’scontrolswitches.SeetheInstructionManualforafull
description of the menus and how to access them.
TABLE 1-4. RANGER COUNT 3000 MENU STRUCTURE
Menu:
C.A.L
S.E.t.U.P
r.E.A.d
U.n.i.t
Menu
Items:
Span
Lin
GEO
End
Reset
D.Scale
Pwr. Un
Zero
Aut.Opt
A.Tare
Bp.Key
Bp.Opt
Bp.Sig
Accum
End
Reset
Stable
Filter
AZT
Light
A.Off
End
Reset
kg
g
lb
oz
lb:oz
End
P.r.i.n.t
C.O.M
L.O.C.k
E.n.d
Menu
Items:
Reset
Stable
A.Print
Contnt
Layout
Data.Tr
End
Reset
Baud
Parity
Stop
Handsh
Alt.Cm
End
L.Cal
L.Setup
L.Read
L.Unit
L.Print
L.COM
End
1.5.4 Menu Navigation
Press and hold Menu until [mMeNU] (Menu) is displayed. When released the first sub-menu
[C.a.l] (Cal) will be shown.
Summary of button navigation functions in menu mode:
-- Yes Allows entry into the displayed menu.
- Accepts the displayed setting and advances to the next item.
-- No Skips by the displayed menu.
- Rejects the displayed setting or menu item and advances to the next
available item.
-- Back Moves backwards through the upper and middle level menus.
- Backs out of a list of selectable items to the previous middle level menu.
-- Exit Exits from menu directly to the active weighing mode.

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-6 Ranger™(Count) 3000 Series Service Manual
1.6 SCALE OPERATION –RANGER 3000
This section contains information on the basic operation of the Ranger 3000 scale.
1.6.1 OVERVIEW OF THE CONTROLS
Figure 1-2. Ranger 3000 Front Display with controls.
TABLE 1-5.
Button
Functions
On/Zero
Off
Yes
Short Press (when on): Sets display to zero
(when off): Turns scale on
Long Press (when on): Turns the scale off
Short Press (in Menu): Selects/accepts displayed setting
Print
Units
No
Short Press: Sends current display value to serial port
(auto print OFF).
Long Press: Toggles through active weighing units
Short Press (in Menu): Toggles through available settings
Function
Mode
Back
Short Press: Selects function setting
Long Press: Selects active Mode
Short Press (in Menu): returns to previous settings
M+
Menu
Exit
Short Press: Accumulates the weight or displays the
accumulated information at 0 load.
Long Press: Enters User Menu
Short Press (in Menu): Quickly exit User Menu
Tare
Short Press: Enter/clear a tare value. Clears the accumulation
when the accumulation information is displayed.
1.6.2 Power ON/OFF
To turn the scale on, press and hold the On/Zero Off button for 2 seconds. The scale
performs a display test, momentarily displays the software version, and then enters the
active weighing mode.
To turn the scale off, press and hold the On/Zero Off button until OFF is displayed.

CHAPTER 1 GETTING STARTED
Ranger™(Count) 3000 Series Service Manual 1-7 Ohaus Corporation www.ohaus.com
The scale can be used on AC power immediately. Allow the battery to charge for 12
hours before using the scale on battery power. The Scale will automatically switch to
battery operation if there is a power failure or the power cord is removed. With AC
power, the scale is constantly charging, so the battery charge indicator will remain lit.
The scale can be operated during charging, and the battery is protected against
overcharging.
For maximum operating time, the battery should be charged at room temperature.
LCD models:
During battery operation, the battery symbol indicates the battery charge level
remaining. The indicator will automatically turn off when the batteries are fully charged.
TABLE 1-6
Symbol
Charge level
0 to 10 % Remaining
11 to 40 % Remaining
41 to 70 % Remaining
71 to 100 % Remaining
LED models:
During battery operation, the battery symbol indicates the battery charging status. When
charging, the symbol will blink slowly and when fully charged the symbol will be turned
off.
TABLE 1-7
Symbol
Charge level
Battery in use:
Symbol displayed
Notes:
When battery symbol blinks fast, approximately 30 minutes working time is left.
When [lo.bat] is displayed, the scale will shut off.
Charging the scale must be performed in a dry environment.
CAUTION: Battery is to be replaced only by an authorized Ohaus service
dealer. Risk of explosion can occur if the rechargeable battery is replaced
with the wrong type or if it is not properly connected. Dispose of the lead
acid battery according to local laws and regulations.

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-8 Ranger™(Count) 3000 Series Service Manual
1.6.3 Menu Setup
Programmable features of the Ranger 3000 scales are contained in menus which are
accessedthroughtheDisplayPanel’scontrolswitches.SeetheInstructionManualforafull
description of the menus and how to access them.
TABLE 1-8. RANGER 3000 MENU STRUCTURE
Menu:
C.A.L
S.E.t.U.P
r.E.A.d
M.O.d.E
Menu
Items:
Span
Lin
GEO
End
Reset
Pwr.Un
Zero
A.Tare
Bp.Sig
Bp.Key
Accum
End
Reset
Stable
Filter
AZT
Light
Sleep1
A.Off
End
Reset
Weigh
Percnt
Count
Check
Dynam
End
U.n.i.t
P.r.i.n.t
C.O.M
L.O.C.k
E.n.d
Menu
Items:
Reset
kg
g
lb
oz
lb:oz
End
Reset
Stable
A.Print
Contnt
Layout
Data.Tr
End
Reset
Baud
Parity
Stop
Handsh
Alt.Cm
End
L.Cal
L.Setup
L.Read
L.Mode
L.Unit
L.Print
L.COM
End
Note: 1only for LED version.
1.6.4 Menu Navigation
Press and hold Menu until [mMeNU] (Menu) is displayed. When released the first sub-menu
[C.a.l] (Calibration) will be shown.
Summary of button navigation functions in menu mode:
-- Yes Allows entry into the displayed menu.
- Accepts the displayed setting and advances to the next item.
-- No Skips by the displayed menu.
- Rejects the displayed setting or menu item and advances to the next
available item.
-- Back Moves backwards through the upper and middle level menus.
- Backs out of a list of selectable items to the previous middle level menu.
-- Exit Exits from menu directly to the active weighing mode.

CHAPTER 1 GETTING STARTED
Ranger™(Count) 3000 Series Service Manual 1-9 Ohaus Corporation www.ohaus.com
1.7 LEGAL FOR TRADE
When the scale is used in trade or a legally controlled application it must be set up, verified
and sealed in accordance with local weights and measures regulations. It is the
responsibility of the purchaser to ensure that all pertinent legal requirements are met.
The Menu Lock switch limits changes to the Cal, Setup, Mode and Unit menus. The switch in
type approved models may set some scale settings as required by the approval agency. The
switch may be secured using paper seals, wire seals or plastic ties.
Note: When LEGAL FOR TRADE is set to ON (LFT Switch in locked position), the menu
settings are affected as follows:
Calibration (C.A.L) menu is not accessible
Unit menu, Auto Tare: are locked at their current setting(s)
Filter is locked at current setting
Stable Range setting is locked at 1d
Zero Range setting is locked at 2%.
Auto-Zero Tracking setting is locked at 0.5d
Stable Only is locked On
Auto Print/ Continuous is disabled
1.7.1 Settings
Before verification and sealing, perform the following steps:
1. Verify that the menu settings meet the local weights and measures regulations.
2. Perform a calibration, see instruction manual.
3. Set the switch to Locked. See figure 1-3.
1.7.2 Verification
The local weights and measures official or authorized service agent must perform the
verification procedure.
1.7.3 Sealing
The local weights and measures official or authorized service agent must apply a security
seal to prevent tampering with the settings. Refer to the illustration below for sealing
methods.
Figure 1-3. Sealing
Paper Seal
Wire Seal
Unlocked Locked with Paper Seal Locked with Wire Seal
Lock Switch

CHAPTER 2DIAGNOSTIC GUIDE
Ranger™(Count) 3000 Series Service Manual 2-1 Ohaus Corporation www.ohaus.com
2.1 TROUBLESHOOTING
This section of the manual contains troubleshooting information. Information is contained to
isolate specific problems using Table 2-4, Diagnostic Guide. Follow all directions step by step.
Make certain that the work area is clean. Handle balance components with care. Use
appropriate Electro-Static Device.
2.2 DIAGNOSTIC GUIDE
Table 2-4 is a Diagnostic Guide designed to help locate the problem area quickly and easily.
The probable causes are listed with the most common cause first. If the first remedy does not fix
the problem, proceed to the next remedy. Before attempting to repair the balance, read all
chapters of this manual to be familiar with the balance components and operation.
2.2.1 Diagnosis
1 Isolate and identify the symptom.
2 Refer to Table 2-4, Diagnostic Guide and locate the symptom.
3 Follow the suggested remedies in the order they appear.
4 Perform the indicated checks, or see the appropriate section of the manual.
5 Repair or replace the defective section of the balance.
NOTE:
If more than one symptom is observed, approach one area at a time,
and remember that the symptoms may be interrelated.
If a problem arises that is not covered in this manual, contact Ohaus Corporation for further
information.

CHAPTER 2DIAGNOSTIC GUIDE
Ohaus Corporation www.ohaus.com 2-2 Ranger™(Count) 3000 Series Service Manual
2.2.2 Checking Load Cells for Trouble
1. Perform a Resistance Test, to determine if the Load Cell is severely damaged or a
short circuit to the frame has occurred.
Note: The Load Cell must be completely disconnected from the Printed Circuit
Board and at no load when the resistance readings are taken.
Using an ohm meter, measure and record resistance between each pair of wires
from the Load Cell, as specified in Table 2-1. Compare the measured readings with
the specified values in Table 2-1.
If the resistance readings are in the range specified, skip to the next section. If they
are outside the expected range, open circuit or short-circuit across any two wires, the
Load Cell is defective: replace it. (See Chapter 3.)
TABLE 2-1. LOAD CELL RESISTANCE READINGS (in Ohms)
Model
Ex+ to Ex–
S+ to S–
Ex+ to S–
Ex+ to S+
Ex–to S+
Ex–to S–
All models
404 ± 10
350 ± 4
289 ± 10
289 ± 10
289 ± 10
289 ± 10
2. Perform an Output Voltage Test:Measure the no load, 50% load and full load
output. The reading should meet the Load Cell specifications. The Load Cell output
should be very close to linear over its capacity range.
NOTE: The following steps involve power applied to the scale. Load Cell solder
contacts can be used as measuring points. See Figure 2-1.
The EXE+ and EXE–wires should be connected to the PCB, and the SIG+ and SIG–
wires must be disconnected. Record the colors for each wire connection before
disconnecting. (See Table 2-2 for typical color code for Ranger 2000 and Ranger
Count 2000.)
TABLE 2-2. COLOR CODE FOR LOAD CELL WIRING*
AMI
BLACK
GREEN
WHITE
RED
EXE–
EXE+
SIG+
SIG–
*Color codes may vary.
–Insert the Platform Support into the Load Cell Frame, place the Platform on top,
and turn on power to the scale.
–Using a voltmeter, measure and record the excitation voltage supplied to the
PCB: with no load on the Platform, measure the voltage across points 4 and 1 of
Load Cell connection on the PCB (+EXE and –EXE). This voltage must be
approximately 3.1 Volts dc with the Load cell connected. If the voltage is lower,
disconnect the Load Cell cable from the PCB and measure again. If the voltage
is 3.1 Volts dc, the Load Cell is defective and must be replaced. If the voltage
remains low, the PCB is defective and must be replaced.

CHAPTER 2DIAGNOSTIC GUIDE
Ranger™(Count) 3000 Series Service Manual 2-3 Ohaus Corporation www.ohaus.com
CAUTION:
IN THE NEXT STEP, DO NOT OVERLOAD THE SCALE BEYOND FULL
CAPACITY RATING.
–Measure the voltages on +SIG and –SIG wires, disconnected from PCB.
Note: Measurements must be made with these wires disconnected from the
PCB. These measurements represent the output of the Load Cell. Record
measurements at Zero Load, 50% and full scale capacities. See Table 2-3 for
typical readings.
Figure 2-1. Top view of main PCB.
NOTE: Table 2-3 indicates typical readings. Actual values can vary, but should
remain linear throughout the range. If readings are out of tolerance, replace the
Load cell. (See Section 3.6.)
TABLE 2-3. LOAD CELL OUTPUT READINGS (in mV/V with 3.1V Excitation)
Model/Capacity
Zero Load
50% Load
100% Load
R31P(E)1502 / 1.5kg
RC31P1502 / 1.5kg
0.492666667
0.992666667
1.49266667
R31P(E)3 / 3kg
RC31P3 / 3kg
0.2956
0.8956
1.4956
R31P(E)6 / 6kg
RC31P6 / 6kg
0.1478
0.7478
1.3478
R31P(E)15 / 15kg
RC31P15 / 15kg
0.0739
0.8239
1.5739
R31P(E)30 / 30 kg
RC31P30 / 30 kg
0.03695
0.78695
1.53695

CHAPTER 2DIAGNOSTIC GUIDE
Ohaus Corporation www.ohaus.com 2-4 Ranger™(Count) 3000 Series Service Manual
2.2.3 Testing the Printed Circuit Board (PCB)
The PCB can be tested by measuring voltages and by using a simulator. The simulator replaces
the Load Cell during testing and is a useful tool for diagnosing problems.
PCB Voltage Measurements
Note: Prior to the voltage measurements, the battery should be fully charged and tested.
1. Disconnect power from the scale, and remove the Top housing. (See Section 3.3.1.)
CAUTION: Disconnect the power from the scale before opening the housing.
2. Connect the AC Adapter to the scale and turn the scale on.
3. Using a DVM, measure the excitation voltage (EXE+ and EXE–in Figure 2-1.)
The reading should be 3.1 volts dc. This is the excitation voltage for the Load Cell
and is regulated. If the voltage is lower, replace the PCB. (See Section 3.4.)
Then perform Operational Tests. (See Chapter 4.)
4. Measure incoming power from the transformer connector shown in Figure 2-1. The
voltage should read 0 volts with power off and above 12 Volts dc with power on.
5. Perform simulator testing.
Simulator Testing
To perform these tests, the use of a Simulator is required. The function of a Simulator is to
simulate the output of a full bridge Load Cell, allowing the scale to be separated from the Load
Cell for the purposes of troubleshooting and calibration. The Load Cell used in the scale is rated
at 2mV/V output with a 3.1 Volt excitation voltage applied.

CHAPTER 2DIAGNOSTIC GUIDE
Ranger™(Count) 3000 Series Service Manual 2-5 Ohaus Corporation www.ohaus.com
General Load Test
This test checks the Main PC Board circuitry by simulating accurate Load Cell voltages at zero
load, 50% and 100% load capacities.
Disconnect power from the scale, and remove the Top housing. (See Section 3.3.1.) Leave the
Mechanical Switch connected to the scale. Disconnect the battery.
1. Disconnect the Load Cell cable from the main PC Board.
2. With the Simulator set to zero, solder its cable leads to their counterparts on the
PCB, using the Load Cell Cable solder points on the PCB. (See Figure 2-1.).
3. Connect a known good AC Adapter to the scale and connect to a power source.
4. Turn on the scale. An under load error may appear. This is normal.
5. Set the scale to indicate weight in kilograms (kg) and set the calibration value to
maximum span value.
6. Adjust the Simulator to simulate 0% load, 50% load and 100% load for the capacity
that the scale is rated for. (See Table 2.3 for values to use.) If the resulting readings
are unstable, the Main PC Board is defective.
7. Use the Simulator to calibrate the scale in the next procedure to verify if the Main PC
Board is good or bad.
Calibration Test
This test calibrates the scale using the simulator and can verify that the Main PC Board is
functioning properly or improperly.
1. With the scale on, enter the scale menu and perform a span calibration.
(See Appendix A.)
2. Follow the scale prompts. When the scale indicates a given weight to be placed
on the scale, set the simulator to an equivalent value based on Table 2-3.
3. Upon completion of calibration, the PCB can be further checked using the Simulator
to simulate various weight values. If simulator settings and weight readings on the
scale agree, the PCB is functional. If the scale readings vary, or do not agree with
readings in Table 2-3, the Main PC Board is defective and should be replaced.
(See Chapter 3.)

CHAPTER 2DIAGNOSTIC GUIDE
Ohaus Corporation www.ohaus.com 2-6 Ranger™(Count) 3000 Series Service Manual
2.2.4 Diagnostic Guide
TABLE 2-4. DIAGNOSTIC GUIDE
Symptom
Possible Cause
Remedy
Cannot turn on
No power to scale
Verify connections and voltage
Poor accuracy
Improper calibration
Unstable environment
Perform calibration
Move scale to suitable location
Cannot calibrate
LFT locked
See chapter 5 for information.
Cannot access mode
Mode not enabled
Enter menu and enable mode
Cannot access unit
Unit not enabled
Enter menu and enable unit
Battery icon flashing
Low Battery error
Connect scale to AC power and charge
the battery
Err 8.1
Power On Error
Weight reading exceeds Power On Zero
limit
Err 8.2
Power On Error
Weight reading below Power On Zero
limit
Err 8.3
Over Range Error
Weight reading exceeds Overload limit
Err 8.4
Under Range Error
Weight reading below Underload limit
Err 8.5
Tare out of range
Adjust tare value to be within range
Err 8.6
Display overflow
Weight exceeds 6 digits
Err 9.5
Calibration data error
Calibration data not present
-------
Busy
Displayed during tare setting, zero
setting, printing
--NO--
Action not allowed
Function not executed
CAL E
Calibration error
Unstable environment
Incorrect calibration weight
Calibration value outside allowed limits
Move the scale to suitable location
Use correct calibration weight
Lo.ref
Low reference weight
warning
Increase reference weight
ref.err
Unacceptable reference
weight
Reference weight too small. Weight on
the pan is too small to define a valid
reference weight. Increase reference
weight.
Battery fails to charge
fully
Battery is defective
Have battery replaced by Ohaus
authorized service dealer.