OHAUS valor 5000 series User manual

SERVICE MANUAL
Valor
™5000 Scales
Ohaus Corporation 19A Chapin Road, P.O. Box 2033, Pine Brook, NJ 07058-2033 [phone]

SERVICE MANUAL
Valor ™5000 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.
© Copyright 2008 Ohaus Corporation, all rights reserved.
TM Registered trademark of Ohaus Corporation.

TABLE OF CONTENTS
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.........................................................................................................1-4
1.5.1 Overview of the Controls....................................................................................1-4
1.5.2 Overview of the Display Indicators.....................................................................1-5
1.5.3 Power On ...........................................................................................................1-5
1.5.4 Power Off ...........................................................................................................1-5
1.6 Legal For Trade (LFT) ...............................................................................................1-6
1.6.1 LFT Setup Procedure.........................................................................................1-6
1.7 Menu Structure..........................................................................................................1-7
CHAPTER 2 TROUBLESHOOTING
2.1 Troubleshooting.........................................................................................................2-1
2.2 Diagnostic Guide .......................................................................................................2-1
2.2.1 Diagnosis............................................................................................................2-1
CHAPTER 3 MAINTENANCE PROCEDURES
3.1 Preventive Maintenance............................................................................................3-1
3.1.1 Preventive Maintenance Checklist .....................................................................3-1
3.2 Opening the Scale.....................................................................................................3-1
3.2.1 Opening Valor 5000 Standard and Washable Models .......................................3-2
3.3 Replacing the Load Cell.............................................................................................3-3
3.4 Replacing the Printed Circuit Board and Display.......................................................3-4
3.5 Replacing the Housing Seals.....................................................................................3-5
3.6 Replacing the Function Label....................................................................................3-6
3.6 Replacing the Plastic Insert.......................................................................................3-6
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. Load Cell Test Using RAMP......................................................................................4-1
4.5 Performance Tests ....................................................................................................4-2
4.5.1 Precision Test.....................................................................................................4-2
4.5.2 Repeatability Test...............................................................................................4-3
4.5.3 Linearity Test......................................................................................................4-5
4.5.4 Off-Center Load Test..........................................................................................4-5
4.5.5 Adjusting Off Center Load..................................................................................4-6
CHAPTER 5 DRAWINGS AND PARTS LISTS
5-1 Valor 5000 V31X3 Scale: Housing & Internal Parts...................................................5-2
5-2 Valor 5000 V31X6 Scale: Housing & Internal Parts...................................................5-4
5-3 Valor 5000 V31XH2 Scale: Housing & Internal Parts................................................5-6
5.4 Valor 5000 V31XH202 Scale: Housing & Internal Parts............................................5-8
5.5 Valor 5000 V31XW3 Scale: Housing & Internal Parts.............................................5-10
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TABLE OF CONTENTS
Page No.
5.6 Valor 5000 V31XW3-M Scale: Housing & Internal Parts.........................................5-12
5.7 Valor 5000 V31XW6 Scale: Housing & Internal Parts.............................................5-14
5.8 Valor 5000 V31XW6-M Scale: Housing & Internal Parts.........................................5-16
5.9 Valor 5000 V31XW301 Scale: Housing & Internal Parts.........................................5-18
5.10 Valor 5000 V31XW301-M Scale: Housing & Internal Parts.....................................5-20
Appendix A STANDARD CALIBRATION
A.1 Calibration.................................................................................................................A-1
Appendix B SERVICE CALIBRATION
B.1 Entering the Service Menu ....................................................................................... B-1
B.2 Ramp........................................................................................................................B-1
B.3 Linear Calibration...................................................................................................... B-2
B.4 Span Calibration....................................................................................................... B-3
B.5 Geographical Adjustment Factor (GEO)................................................................... B-4
B.6 Expanded Readability (E.PAnd)............................................................................... B-5
APPENDIX C SOFTWARE SERVICE TOOL INSTRUCTIONS
C.1 Hardware and Software Setup..................................................................................C-1
C.2 Configuring the Scale (after replacing the PCB or Load Cell) ..................................C-3
APPENDIX D GEOGRAPHICAL ADJUSTMENT VALUES
TABLE D-1. Geographical Adjustment Values...................................................................D-1
LIST OF TABLES
TABLE NO. TITLE Page No.
1-1 Specifications........................................................................................................1-2
1-2 Capacity and Readability.......................................................................................1-3
1-3 Functions of Display Controls................................................................................1-4
1-4 Display Indicators..................................................................................................1-5
1-5 Valor 5000 Menu Structure ...................................................................................1-7
2-1 Diagnostic Guide...................................................................................................2-2
4-1 Calibration Mass Values........................................................................................1-2
4-2 Tolerances ............................................................................................................4-2
4-3 Repeatability Worksheet .......................................................................................4-4
4-4 Linearity Test Masses ...........................................................................................4-5
5-1 Valor 5000 V31X3 Scale: Housing & Internal Parts..............................................5-3
5-2 Valor 5000 V31X6 Scale: Housing & Internal Parts..............................................5-5
5-3 Valor 5000 V31XH2 Scale: Housing & Internal Parts............................................5-7
5.4 Valor 5000 V31XH202 Scale: Housing & Internal Parts........................................5-9
5.5 Valor 5000 V31XW3 Scale: Housing & Internal Parts.........................................5-11
5.6 Valor 5000 V31XW3-M Scale: Housing & Internal Parts.....................................5-13
5.7 Valor 5000 V31XW6 Scale: Housing & Internal Parts.........................................5-15
5.8 Valor 5000 V31XW6-M Scale: Housing & Internal Parts.....................................5-17
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TABLE OF CONTENTS
TABLE NO. TITLE Page No.
5.9 Valor 5000 V31XW301 Scale: Housing & Internal Parts.....................................5-19
5.10 Valor 5000 V31XW301-M Scale: Housing & Internal Parts.................................5-21
D-1. Geographical Adjustment Values.........................................................................D-1
LIST OF ILLUSTRATIONS
FIGURE NO. TITLE
1-1 Power Connection and Seal..................................................................................1-4
1-2 Valor 5000 Display................................................................................................1-4
1-3 Valor 5000 Display Indicators................................................................................1-5
1-4 LFT/Cal Lock Switch .............................................................................................1-6
3-1 Scale Bottom.........................................................................................................3-2
3-2 Technique for separating Top and Bottom Housing on Valor 5000 ......................3-2
3-3 Red lock between battery compartments..............................................................3-3
3-4 Printed Circuit Board and Display .........................................................................3-4
3-5 Bottom of Valor 5000 Xtreme W, with Battery Cover on.......................................3-5
3-6 Plastic Insert and Function Label..........................................................................3-6
3-7 Plastic Insert, viewed from inside Top Housing.....................................................3-6
4-1 Segment Display...................................................................................................4-1
4-2 Scale drawing of Valor 5000 Load Cell and Weighing Pan...................................4-6
5-1 Valor 5000 V31X3 Scale: Housing & Internal Parts..............................................5-2
5-2 Valor 5000 V31X6 Scale: Housing & Internal Parts..............................................5-4
5-3 Valor 5000 V31XH2 Scale: Housing & Internal Parts............................................5-6
5.4 Valor 5000 V31XH202 Scale: Housing & Internal Parts........................................5-8
5.5 Valor 5000 V31XW3 Scale: Housing & Internal Parts.........................................5-10
5.6 Valor 5000 V31XW3-M Scale: Housing & Internal Parts.....................................5-12
5.7 Valor 5000 V31XW6 Scale: Housing & Internal Parts.........................................5-14
5.8 Valor 5000 V31XW6-M Scale: Housing & Internal Parts.....................................5-16
5.9 Valor 5000 V31XW301 Scale: Housing & Internal Parts.....................................5-18
5.10 Valor 5000 V31XW301-M Scale: Housing & Internal Parts.................................5-20
C-1 RS232 Interface connected to Service Adapter, connected to PCB....................C-1
C-2 Com Port Configuration screen with correct settings...........................................C-2
C-3 Config Tool’s Test Command screen...................................................................C-2
C-4 The Config Tool’s Configuration Screen ..............................................................C-3
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TABLE OF CONTENTS
Valor™ 5000 Series Service Manual iv Ohaus Corporation www.ohaus.com

CHAPTER 1 GETTING STARTED
1.1 INTRODUCTION
This service manual contains the information needed to perform routine maintenance and
service on the Ohaus Valor 5000 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 Valor 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, adjust the GEO Factor, and use E.PAnd to set the readability to
1/10th of the standard readability.
Appendix C Geographical Adjustment Values –The chart of scale settings for every
geographical latitude away from the equator (in degrees and minutes) and every elevation
above sea level (in meters or feet).
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.
Valor™ 5000 Series Service Manual 1-1 Ohaus Corporation www.ohaus.com

CHAPTER 1 GETTING STARTED
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. Razor blades.
1.4 SERVICE STRATEGY
The repair method for the Valor 5000 Series Scales is direct substitution of major assemblies.
The available repair parts are listed and illustrated in Chapter 5.
There are four major replaceable assemblies:
– Cover Assembly with Membrane Switch
– Load Cell Assembly with Frame
– Lead Acid Rechargeable Battery and
– Main PC Board with LCD.
The Load Cell, LCD and Membrane Switch may also be ordered and replaced separately.
This service manual contains sufficient information to isolate the problem, replace the
component, test and restore the scale to original factory specifications.
Ohaus Corporation www.ohaus.com 1-2 Valor™ 5000 Series Service Manual

CHAPTER 1 GETTING STARTED
1.5 SPECIFICATIONS
Complete specifications for the Ohaus Valor 5000 Scales are listed in Tables 1-1 and 1-2.
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, STANDARD DENSITY MODELS
Model V51P3 V51P6 V51P15 V51P30
Capacity x Readability
Max x d (non-
approved)
3 kg x 0.0005 kg
3000 g x 0.5 g
6 lb x 0.001 lb
96 oz x 0.02 oz
96 oz x 1/4 oz
6 lb 0 oz x 0.1 oz
6 lb 0 oz x 1/4 oz
6 kg x 0.001 kg
6000 g x 1 g
15 lb x 0.002 lb
240 oz x .05 oz
240 oz x 1/4 oz
15 lb x 0.1 oz
15 lb x 1/4 oz
15 kg x 0.002 kg
15000 g x 2 g
30 lb x 0.005 lb
480 oz x 0.1 oz
480 oz x 1/4 oz
30 lb 0 oz x 0.1 oz
30 lb 0 oz x 1/4 oz
30 kg x 0.005 kg
30000 g x 5 g
60 lb x 0.01 lb
960 oz x 0.2 oz
960 oz x 1/4 oz
60 lb 0 oz x 0.2 oz
60 lb 0 oz x 1/4 oz
Maximum Displayed
Resolution 6000 7500 7500 6000
Capacity x Readability
Max x d (approved) 3 kg x 0.001 kg
3000 g x 1 g
6 lb x 0.002 lb
96 oz x 0.05 oz
96 oz x 1/4 oz
6 kg x 0.002 kg
6000 g x 2 g
15 lb x 0.005 lb
240 oz x .1 oz
240 oz x 1/4 oz
15 kg x 0.005 kg
15000 g x 5 g
30 lb x 0.01 lb
480 oz x 0.2 oz
480 oz x 1/4 oz
30 kg x 0.01 kg
30000 g x 10 g
60 lb x 0.02 lb
960 oz x 0.5 oz
960 oz x 1/4 oz
Approved Resolution 3000 3000 3000 3000
Repeatability (kg) 0.001 0.002 0.005 0.01
Linearity (kg) (+/-) 0.001 0.002 0.005 0.01
Weighing Units g, kg, lb, oz (decimal/fractional), lb:oz (decimal/fractional oz)
Application Modes Weighing, Checkweighing, Percentage
Checkweigh
Indication 3 LEDs (yellow, green, red) with configurable alert beeper
Power 9-12 VDC 0.5A-0.8A AC adaptor;
internal rechargeable sealed lead-acid battery
Battery Operating
Time 120 hours
Tare range To capacity by subtraction
Stabilization Time Within 2 seconds
Auto zero tracking Off, 0.5, 1 or 3 divisions
Operating
Temperature Range –10° to 40°C / 14° to 104°F
Storage
Temperature Range – 40° to 70°C / – 40° to 104°F
Approved
Temperature Range 0° to 40°C / 32° to 104°F
Pan Size (D X W) 209 x 209 mm / 8.2 x 8.2 in
Scale dimensions 300 x 223 x 71 mm / 9 x 12 x 2.8 in.
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CHAPTER 1 GETTING STARTED
1.4 SPECIFICATIONS
TABLE 1-2. SPECIFICATIONS, HIGH DENSITY MODELS
Model V51PH3 V51PH6 V51PH15 V51PH30
Capacity x Readability
Max x d (non-
approved)
3 kg x 0.0001 kg
3000 g x 0.1 g
6 lb x 0.0002 lb
96 oz x 0.005 oz
96 oz x 1/4 oz
6 lb 0 oz x 0.1 oz
6 lb 0 oz x 1/4 oz
6 kg x 0.0002 kg
6000 g x 0.2 g
15 lb x 0.001 lb
240 oz x .01 oz
240 oz x 1/4 oz
15 lb x 0.1 oz
15 lb x 1/4 oz
15 kg x 0.001 kg
15000 g x 1 g
30 lb x 0.001 lb
480 oz x 0.02 oz
480 oz x 1/4 oz
30 lb 0 oz x 0.1 oz
30 lb 0 oz x 1/4 oz
30 kg x 0.001 kg
30000 g x 1 g
60 lb x 0.002 lb
960 oz x 0.05 oz
960 oz x 1/4 oz
60 lb 0 oz x 0.1 oz
60 lb 0 oz x 1/4 oz
Maximum Displayed
Resolution 30000 30000 30000 30000
Repeatability (kg) 0.0002 0.0004 0.002 0.002
Linearity (kg) (+/-) 0.0002 0.0004 0.002 0.002
Weighing Units g, kg, lb, oz (decimal/fractional), lb:oz (decimal/fractional oz)
Application Modes Weighing, Checkweighing, Percentage
Checkweigh
Indication 3 LEDs (yellow, green, red) with configurable alert beeper
Power 9-12 VDC 0.5A-0.8A AC adaptor;
internal rechargeable sealed lead-acid battery
Battery Operating
Time 120 hours
Tare range To capacity by subtraction
Stabilization Time Within 2 seconds
Auto zero tracking Off, 0.5, 1 or 3 divisions
Operating
Temperature Range –10° to 40°C / 14° to 104°F
Storage
Temperature Range – 40° to 70°C / – 40° to 104°F
Approved
Temperature Range 0° to 40°C / 32° to 104°F
Pan Size (D X W) 209 x 209 mm / 8.2 x 8.2 in
Scale dimensions 300 x 223 x 71 mm / 9 x 12 x 2.8 in.
Ohaus Corporation www.ohaus.com 1-4 Valor™ 5000 Series Service Manual

CHAPTER 1 GETTING STARTED
1.5 SCALE OPERATION
This section contains information on the basic operation of the scale.
1.5.1 OVERVIEW OF THE CONTROLS
Figure 1-1. Valor 5000 Display.
TABLE 1-3. FUNCTIONS OF DISPLAY CONTROLS
Button/
Function
Primary
Function
(short press)
ON / ZERO
If scale is off,
turns scale on.
If scale is on,
sets zero.
G/N/T
Momentarily
Displays Gross
Net and Tare
values
TARGET
Initiates target
setting mode.
TARE
Sets tare.
Clears tare, if
pan is empty.
Secondary
Function
(long press)
Off
If scale is on,
turns scale off.
Units
Changes
weighing unit
Menu
Enters menu
mode.
None
Menu
Function Yes
Accepts current
setting and
advances to the
next menu item
No
Rejects current
setting or menu
item and
advances to the
next available
item
Back
Reverts back to
previous menu
item.
Exit
• Immediately
exits menu mode
• Aborts
calibration in
progress
Target Setting
Function Shifts to next
digit Increments value of the active digit Accepts current displayed value. Changes sign (+ / –) of
displayed value.
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CHAPTER 1 GETTING STARTED
1.5.2 OVERVIEW OF THE DISPLAY INDICATORS 7
8
Not
used
Figure 1-2. Display Indicators.
2 3
1 6
45
TABLE 1-4. DISPLAY INDICATORS
No. Function
1Indicates that the measured value has become stable
2 Center of Zero indicator
3 Checkweigher mode indicator
4 Net indicator
5 Tare indicator
6 Symbols for weighing modes: kg – Kilograms, g – grams, lb:oz – Pounds & Ounces,
lb – Pounds, oz – Ounces, 3/8– Fractional ounces (P in % mode)
7 Battery charging indicator
8 Pound:Ounce separator
1.5.3 Power
Check that the AC adapter supports the
voltage in use locally. Then plug the adapter
into the receptacle marked “Power In” located
on the underside of the scale.
The first time the scale is powered on, the
internal rechargeable battery should be fully
charged. The scale can be operated during
the charging process. The battery is protected
against over charging and the scale can
remain connected to the AC power line. The
display’s battery symbol will stay lit until the
battery is fully charged, and then it will turn off.
Foot Switch
Receptacle
“Power In”
Rece
p
tacle
Figure 1-3. Scale Bottom
The scale will automatically switch to battery operation if the power cord is removed or there is a
power failure. A fully charged battery can operate the scale for up to 120 hours (with the
backlight off). During battery operation, the battery symbol will light to show the current status
of the battery (1 segment = 25% capacity). A flashing symbol indicates that the battery requires
recharging. The scale will automatically shut off when the battery is fully discharged.
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CHAPTER 1 GETTING STARTED
1.5.4 Power ON
With power applied, press ON/ZERO/Off. Allow 20 minutes warm-up time. The scale should
be calibrated before use. (See Appendix A.)
1.5.4 Power OFF
With the scale on, press and hold the ON/ZERO Off button until OFF is displayed.
1.5.5 Menu Setup
Programmable features of the Valor 5000 scales are contained in menus which are accessed by
pressing TARGET/Menu on the Display Panel. The menu structure consists of three levels:
Main, Sub-menu, and Menu item. The Main menu contains the Sub-menus and each Sub-menu
contains several Menu items. Each Menu item contains two or more settings.
Use the four buttons marked with Yes, No, Back and Exit to navigate through the menus.
(See Figure 1-4.) For more detail on using the menus, see the Instruction Manual.
– Yes Enters the displayed sub-menu or menu item and accepts the displayed setting.
– No Skips to the next sub-menu or menu item and changes the displayed setting.
– Back Goes back to the previous sub-menu or menu item.
– Exit Immediately exits the Menu mode.
Figure 1-4. Valor 5000 Menu Structure
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CHAPTER 1 GETTING STARTED
1.6 Legal for Trade Settings
Consult local weights and measures officials for regulations before placing the scale in Legal for
Trade mode. When the LFT menu setting is On, the following conditions apply:
– The Calibration (CAL) sub-menu is hidden.
– The Calibration Lock (LCAL) menu item is hidden.
– The Auto Zero Tracking (AZt) menu item is set to 0.5 d.
– lb:oz and Punits are disabled.
To regain access to the locked menu settings, break
the seal holding the Security Slide on the bottom of
the scale closed, and shift the slide open. (See
Figure 1-6.) This turns LFT off by moving a menu-
lock switch on the PCB to the Off position. (See
Figure 1-5.)
After the LFT/CAL Lock setting has been turned off,
the scale must be inspected and sealed in
accordance with local weights and measures
regulations before it can be used in LFT mode again.
Figure 1-5. Menu-lock switch on PCB.
1.6.1 Sealing the Scale
When used in conjunction with the Lockout Menu and the Security Switch, the scale may be
sealed to prevent or detect unauthorized changes to scale settings. For Legal for Trade
applications, set the LFT menu item to ON, set the Security Slide to the On position by sliding
the switch to cover the screw, and then seal the scale to prevent access to the metrological
parameters. Seal the scale according to the local weights and measures regulations.
To regain access to the scale settings, break the seal and set the security slide to the OFF
position.
ON OFF
Security
Slide
Figure 1-5. Security Switch Settings.
Ohaus Corporation www.ohaus.com 1-8 Valor™ 5000 Series Service Manual

CHAPTER 2 DIAGNOSTIC GUIDE
2.1 TROUBLESHOOTING
This section of the manual contains troubleshooting information. Information is contained to
isolate specific problems using Table 2-1, Diagnostic Guide. Follow all directions step by step.
Make certain that the work area is clean. Handle scale components with care. Use appropriate
Electro-Static Device.
2.2 DIAGNOSTIC GUIDE
Table 2-1 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 scale, read all
chapters of this manual to be familiar with the scale components and operation.
2.2.1 Diagnosis
1. Isolate and identify the symptom
2. Refer to Table 2-1, 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 scale.
Note: If more than one symptom is observed, approach one area at a time,
and remember that the symptoms may be interrelated.
If there is a problem that is not covered in this manual, contact Ohaus for further information.
2.2.2 Testing the Membrane Switch
If the scale does not turn on, or menus cannot be accessed, the Membrane Switch may be
defective. It can be tested after removing the Top Housing. (See Section 3.1.)
1. Using an Ohmmeter, measure the resistance between pin 5 and each other pin on
the Membrane Switch Cable. (See Figure 2-2, next page.) The readings should be
infinite resistance.
2. Press each button and check that the resistance is under 50 ohms for each button.
3. Check that the Membrane Switch is not shorted to the Top Housing case.
Check pins 1 through 5 to the case, which should be infinite resistance.
4. If any test fails, the Membrane Switch is defective. Replace it. (See Section 3.5.)
Figure 2-1. Membrane Switch Cable connections.
Valor™ 5000 Series Service Manual 2-1 Ohaus Corporation www.ohaus.com

CHAPTER 2 DIAGNOSTIC GUIDE
2.2.3 Checking Load Cells for Trouble
This section contains three methods of testing the Load cell.
1. Perform a Ramp Test. (See Appendix B.) If the Ramp Test passes, continue with
the rest of this procedure.
2. 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.
Remove the Load Cell cable connector from the PC Board. Using an Ohmmeter,
measure Load Cell Resistance Readings on the cable. (See Table 2-1.) If the
resistance readings vary more than the table readings allow, replace the Load Cell.
(See Chapter 3.)
TABLE 2-1. LOAD CELL RESISTANCE READINGS (in Ohms)
MEASUREMENT POINTS* READING
Pins 1& 4 (Exe+ to Exe–)
Pins 2& 3 (S+ to S–) 408 ± 10 350 ± 4
*See Figure 2-2.
Figure 2-2. Main Printed Circuit Board Connections
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CHAPTER 2 DIAGNOSTIC GUIDE
2.2.2 Checking Load Cells for Trouble
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 2-2.)
TABLE 2-2. COLOR CODE FOR LOAD CELL WIRING*
BLACK RED GREEN WHITE
EXE+ SIG+ EXE– SIG–
*Color codes may vary.
– Insert the Pan Support Caps 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 1 and 4 of
the Load Cell connection on the PCB: +EXE and –EXE. (See Figure 2-2.) This
voltage must be approximately 5.0 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 5 Volts dc, the Load Cell is defective and must be
replaced. If the voltage remains low, the PCB is defective and must be replaced.
CAUTION:
IN THE NEXT STEP, DO NOT OVERLOAD THE SCALE BEYOND FULL
CAPACITY RATING.
– Measure the voltages on +SIG and –SIG wires, disconnected from the PCB
(points 2 and 3 in Figure 2-2). 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.
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 with 5V Excitation)
Capacity Zero Load 50% Load 100% Load
3kg 1.2 ± 1.5 Zero + 2.2 Zero + 4.4
6kg 0.4 ± 1.5 Zero + 2.0 Zero + 4.0
15kg 0.2 ± 1.5 Zero ± 2.5 Zero ± 5.0
30kg 0.2 ± 1.5 Zero ± 3.0 Zero ± 6.0
Valor™ 5000 Series Service Manual 2-3 Ohaus Corporation www.ohaus.com

CHAPTER 2 DIAGNOSTIC GUIDE
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 3.1.)
Leave the Membrane Switch connected to the scale.
2. Disconnect the Battery from the PCB.
3. Connect the AC Adapter to the scale and turn the scale on.
4. Using a DVM, measure the excitation voltage across pins 1 and 4 of J1. (See Figure
2-2.) The reading should be 5 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.)
5. Measure incoming power from the AC Adapter connector shown in Figure 2-2. The
voltage should read between 9 and 14 volts dc with power off and above 9 Volts dc
with power on.
6. With the battery disconnected from the PCB, measure voltage across pins 1 and 3
on the battery connector on the PCB. (See Figure 2-2.) The voltage should read
1 to 3 Volts dc.
7. Connect the battery to the PCB and measure the voltage across pins 1 and 3 on the
battery connector. The full battery voltage should read a minimum of 6.0 Volts dc.
If the voltage is lower, the battery may require charging or it may be defective. Test
the battery. (See Section 2.5.)
8. Perform simulator testing.
Ohaus Corporation www.ohaus.com 2-4 Valor™ 5000 Series Service Manual