OHAUS STARTER 5000 User manual

STARTER 5000
BENCH TOP pH METER
SERVICE MANUAL
Ohaus Corporation 7 Campus Drive, Suite 310, Parsippany, NJ 07054 [phone]

STARTER 5000
BENCH TOP pH METER
SERVICE MANUAL
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 2014 Ohaus Corporation, all rights reserved.
® Registered trademark of Ohaus Corporation.

TABLE OF CONTENTS
ST5000 Bench Top pH Meter Service Manual i Ohaus Corporation www.ohaus.com
CHAPTER 1 GETTING STARTED Page No.
1 Introduction..............................................................................................................1-1
1.1 Service Facilities......................................................................................................1-1
1.2 Tools and Test Equipment Required........................................................................1-2
1.2.1 Standard Tools and Test Equipment.................................................................1-2
1.4 Specifications...........................................................................................................1-3
1.5 Compliances............................................................................................................1-5
1.6 Buffer Groups...........................................................................................................1-6
1.7 Controls ...................................................................................................................1-8
1.7.2 Icons.....................................................................................................................1-9
1.7.3 Sensor Condition ID .............................................................................................1-9
CHAPTER 2 DIAGNOSIS
2. Diagnosis.................................................................................................................2-1
2.1 Equipment Setup and Examination..........................................................................2-1
2.2 Preliminary Checks..................................................................................................2-1
2.3 Troubleshooting Tables............................................................................................2-1
2.4 Proper Connection of Electrode with Meter..............................................................2-3
2.5 pH Electrodes Preparation Before Calibration or Measurement ...............................2-3
2.6 Storage the pH Electrode.........................................................................................2-3
2.7 Diaphragm Contamination Issue..............................................................................2-4
2.8 Reconditioning of the Dry Glass Membrane.............................................................2-4
2.9 Lifetime of an Electrode ...........................................................................................2-4
2.10 Symptoms for an Aged Electrode.............................................................................2-5
CHAPTER 3 PREVENTIVE MAINTENANCE
3. Preventive Maintenance...........................................................................................3-1
3.1 Service Strategy.......................................................................................................3-1
3.2 Opening the Meter ...................................................................................................3-1
3.3 Separating the Top and Bottom Housing..................................................................3-1
3.4 Removing the Main PCBA........................................................................................3-3
3.5 Removing the LCD Touch Panel..............................................................................3-4
3.6 Removing the Protective Rubber Seal......................................................................3-5
CHAPTER 4 DRAWINGS AND PART LISTS
4 Drawings and Part Lists ...........................................................................................4-1
APPENDIX A ST5000 SERVICE MODE
A Service Mode..........................................................................................................A-1
A.1 Service Mode..........................................................................................................A-1
A.2 Entering to Service Mode........................................................................................A-1
A.3 Service Password ...................................................................................................A-2
A.4 Options In Service Mode.........................................................................................A-3

TABLE OF CONTENTS
Ohaus Corporation www.ohaus.com ii ST5000 Bench Top pH Meter Service Manual
APPENDIX B SERVICE AND REPAIR TOOLS Page No.
B Software Service And Repair Tool ..........................................................................B-1
B.1 Software Installation And Software Selection..........................................................B-1
B.2 Product Selection....................................................................................................B-2
B.3 Update the Software in ST5000 ..............................................................................B-2
B.4 Configuring AppProgramer......................................................................................B-4
LIST OF TABLES
TABLE NO. TITLE Page No.
1-1 Specifications ......................................................................................................1-3
1-2 Icons....................................................................................................................1-9
2-1 Equipment Will Not Turn ON with AC Adapter.....................................................2-1
2-2 Equipment Touch Panel Does Not Response......................................................2-2
2-3 Measuring Results In Consistence.......................................................................2-2
4-1 ST5000 pH Meter Bench Top Spare Parts...........................................................4-3
LIST OF ILLUSTRATIONS
FIGURE NO. TITLE Page No.
1-1 Controls………………………………………………………………………………….1-8
3-1 Screws That Securing the Housing......................................................................3-1
3-2 Connection between LCD Panel with Bottom Housing.........................................3-2
3-3 Film Cable Connection ........................................................................................3-2
3-4 Screws Holding the Main PCBA with Bottom Housing.........................................3-3
3-5 Screws Holding the LCD Panel to Top Housing...................................................3-4
3-6 Screws Holding the Protective Rubber Seal.........................................................3-5
3-7 Protective Rubber Seal Removed........................................................................3-5
4-1 ST5000 pH Meter Bench Top ..............................................................................4-2
A-1 Select System Setting.......................................................................................... A1
A-2 Select Menu........................................................................................................A-1
A-3 Service Menu Enter Password............................................................................A-1
A-4 ST5000 Password Generator .............................................................................A-2
A-5 Service Menu Screen .........................................................................................A-2
B-1 Software Selection..............................................................................................B-1
B-2 Product Selection ...............................................................................................B-2
B-3 Download AppProgrammer.................................................................................B-3
B-4 Com Port Configuration ......................................................................................B-4
B-5 Image File Selection...........................................................................................B-4
B-6 Progress.............................................................................................................B-5
B-7 Status.................................................................................................................B-5
B-8 Software Downloading in Progress.....................................................................B-6
B-9 Software Downloading Completed Successfully.................................................B-7
B-10 Closing the Application.......................................................................................B-7

CHAPTER 1 GETTING STARTED
ST5000 Bench Top pH Meter Service Manual 1-1 Ohaus Corporation www.ohaus.com
1. INTRODUCTION
This service manual contains instructions for the diagnosis and repair work to be performed by
Ohaus Dealers or Ohaus authorized service centers. Knowledge of the operation of the
equipment is assumed. Instruction manuals may be required with this service manual. For
complete information on operation, refer to the Instruction Manual.
This manual covers maintenance on the following:
ST5000 Bench Top pH Meter
The contents of this manual are contained in three chapters.
Chapter 1 Introduction - Contains information about service facilities, tools, test equipment,
service strategy, equipment specifications, Buffer groups and equipment controls.
Chapter 2 Diagnosis- Contains Preliminary checks, troubleshooting tables, Proper handling of
electrode, pH electrode preparation before calibration and measurement, storage of pH
electrodes, diaphragm contamination issue, reconditioning of the dry glass electrode, life span
of an electrode and symptoms for an aged electrode.
Chapter 3 Preventive Maintenance- Contains information on how to replace major
components.
Chapter 4 Parts Lists - Contains overall views identifying all major serviceable replacement
components with associated parts lists.
Appendix A Service Mode- Contains instruction how to entering to equipment Service Mode.
Appendix B Repair & Service Tool- Contain instruction how to upgrade equipment using
Repair and Service Tool.
1.1 SERVICE FACILITIES
To service the equipment, the service area should meet the following requirements:
Must have a stable power supply.
Be clean and free of excessive dust.

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-2 ST5000 Bench Top pH Meter Service Manual
1.2 TOOLS AND EQUIPMENT
1.2.1 Standard Tools and Test Equipment
The service shop should contain the following equipment:
1. Digital Voltmeter (DVM).
2. Standard Electronics tool kit.
3. Razor blades.
4. Respective Buffer Groups. (1-6)
5. Respective Electrodes.
1.3 SERVICE STRATEGY
The repair method for the ST5000 Table Top pH Meter available repair parts are listed in Table
4-1.
1.4 SPECIFICATIONS
Specifications
Ambient conditions
* Indoor use only
* Altitude: Up to 2000 m
* Specified Temperature range: 5°C to 40°C
* Humidity: maximum relative humidity 80 % for temperatures up to 30°C decreasing linearly to
50% relative humidity at 40°C
* Mains supply voltage fluctuations: up to ±10% of the nominal voltage
* Installation category II
* Pollution degree: 2
* Operability is assured at ambient temperatures between 5°C to 40°C

CHAPTER 1 GETTING STARTED
ST5000 Bench Top pH Meter Service Manual 1-3 Ohaus Corporation www.ohaus.com
1.4 SPECIFICATIONS
TABLE 1-1. SPECIFICATIONS

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-4 ST5000 Bench Top pH Meter Service Manual
1.5 COMPLIANCES.

CHAPTER 1 GETTING STARTED
ST5000 Bench Top pH Meter Service Manual 1-5 Ohaus Corporation www.ohaus.com
1.6 BUFFER GROUPS.
STARTER 5000 automatically correct for the temperature dependence of the buffer group pH
value given in the following tables. Please choose the buffer group you want before calibration.
JJG119 ((Ref. 25°C, 0.01pH)
Temp °C 1.68 4.00 6.86 9.18 12.46
5 1.67 4.00 6.95 9.39 13.21
10 1.67 4.00 6.92 9.33 13.01
15 1.67 4.00 6.90 9.28 12.82
20 1.68 4.00 6.88 9.23 12.64
25 1.68 4.00 6.86 9.18 12.46
30 1.68 4.01 6.85 9.14 12.29
35 1.69 4.02 6.84 9.11 12.13
40 1.69 4.03 6.84 9.07 11.98
45 1.70 4.04 6.83 9.04 11.83
50 1.71 4.06 6.83 9.02 11.70
US standard (Ref. 25°C)
Temp °C 1.68 4.01 7.00 10.01
5 1.67 4.01 7.09 10.25
10 1.67 4.00 7.06 10.18
15 1.67 4.00 7.04 10.12
20 1.68 4.00 7.02 10.06
25 1.68 4.01 7.00 10.01
30 1.68 4.01 6.99 9.97
35 1.69 4.02 6.98 9.93
40 1.69 4.03 6.97 9.89
45 1.70 4.05 6.97 9.86
50 1.71 4.06 6.96 9.83
Europe standard (Ref. 25°C)
Temp°C 2.00 4.01 7.00 9.21 11.00
5 2.02 4.01 7.09 9.45 11.72
10 2.01 4.00 7.06 9.38 11.54
15 2.00 4.00 7.04 9.32 11.36
20 2.00 4.00 7.02 9.26 11.18
25 2.00 4.01 7.00 9.21 11.00
30 1.99 4.01 6.99 9.16 10.82
35 1.99 4.02 6.98 9.11 10.64
40 1.98 4.03 6.97 9.06 10.46
45 1.98 4.04 6.97 9.03 10.28
50 1.98 4.06 6.97 8.99 10.10

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-6 ST5000 Bench Top pH Meter Service Manual
1.6 BUFFER GROUPS.
MERCK (Ref. 20°C)
Temp °C 2.00 4.00 7.00 9.00 12.00
5 2.01 4.04 7.07 9.16 12.41
10 2.01 4.02 7.05 9.11 12.26
15 2.00 4.01 7.02 9.05 12.10
20 2.00 4.00 7.00 9.00 12.00
25 2.00 4.01 6.98 8.95 11.88
30 2.00 4.01 6.98 8.91 11.72
35 2.00 4.01 6.96 8.88 11.67
40 2.00 4.01 6.95 8.85 11.54
45 2.00 4.01 6.95 8.82 11.44
50 2.00 4.00 6.95 8.79 11.33
DIN (19267) (Ref. 25°C)
Temp°C 1.09 4.65 6.79 9.23 12.75
5 1.08 4.67 6.87 9.43 13.63
10 1.09 4.66 6.84 9.37 13.37
15 1.09 4.66 6.82 9.32 13.16
20 1.09 4.65 6.80 9.27 12.96
25 1.09 4.65 6.79 9.23 12.75
30 1.10 4.65 6.78 9.18 12.61
35 1.10 4.65 6.77 9.13 12.45
40 1.10 4.66 6.76 9.09 12.29
45 1.10 4.67 6.76 9.04 12.09
50 1.11 4.68 6.76 9.00 11.98
JIS Z 8802 (Ref. 25°C)
Temp°C 1.679 4.008 6.865 9.180
5 1.668 3.999 6.951 9.395
10 1.670 3.998 6.923 9.332
15 1.672 3.999 6.900 9.276
20 1.675 4.002 6.881 9.225
25 1.679 4.008 6.865 9.180
30 1.683 4.015 6.853 9.139
35 1.688 4.024 6.844 9.102
40 1.694 4.035 6.838 9.068
45 1.700 4.047 6.834 9.038
50 1.707 4.060 6.833 9.011

CHAPTER 1 GETTING STARTED
ST5000 Bench Top pH Meter Service Manual 1-7 Ohaus Corporation www.ohaus.com
DIN(19266) / NIST (Ref. 25°C)
Temp°C 1.680 4.008 6.865 9.183 12.454
5 1.668 4.004 6.950 9.392 13.207
10 1.670 4.001 6.922 9.331 13.003
15 1.672 4.001 6.900 9.277 12.810
20 1.676 4.003 6.880 9.228 12.627
25 1.680 4.008 6.865 9.183 12.454
30 1.685 4.015 6.853 9.144 12.289
35 1.691 4.026 6.845 9.110 12.133
40 1.697 4.036 6.837 9.076 11.984
45 1.704 4.049 6.834 9.046 11.841
50 1.712 4.064 6.833 9.018 11.705
JJG119 (Ref. 25°C, 0.001pH)
Temp °C 1.680 4.003 6.864 9.182 12460
5 1.669 3.999 6.949 9.391 13.210
10 1.671 3.996 6.921 9.330 13.011
15 1.673 3.996 6.898 9.276 12.820
20 1.676 3.998 6.879 9.226 12.637
25 1.680 4.003 6.864 9.182 12.460
30 1.684 4.010 6.852 9.142 12.292
35 1.688 4.019 6.844 9.105 12.130
40 1.694 4.029 6.838 9.072 11.975
45 1.700 4.042 6.834 9.042 11.828
50 1.706 4.055 6.833 9.015 11.697

CHAPTER 1 GETTING STARTED
Ohaus Corporation www.ohaus.com 1-8 ST5000 Bench Top pH Meter Service Manual
1.7. CONTROLS
Figure 1-1. Controls.
1.7.1 Turn ON and OFF the Meter.
To turn off the meter, please tap the turn-off button to enter the turn-off interface, then
tap to turn-off the meter or tap to go back to main interface again.

CHAPTER 1 GETTING STARTED
ST5000 Bench Top pH Meter Service Manual 1-9 Ohaus Corporation www.ohaus.com
1.7.2 ICONS.
Table 1-2. Icons.
1.7.3 SENSOR CONDITION ID.
There Are 3 sensor conditions ID.

CHAPTER 2 DIAGNOSIS
ST5000 Bench Top pH Meter Service Manual 2-1 Ohaus Corporation www.ohaus.com
2. DIAGNOSIS
This section contains information needed to properly evaluate the reported problem and
diagnose its cause.
2.1 EQUIPMENT SETUP AND EXAMINATION
Set up the equipment according to the Instruction manual. And examine the equipment for any
physical damage.
2.2 PRELIMINARY CHECKS
Power-up the equipment using the equipment’s original AC adapter. In the case where the
equipment will not power up, check the AC adapter.
2.3 TROUBLESHOOTING TABLES
Troubleshooting tables 2-1 through 2-2 identifies actual types of problems that could be
encountered with the equipment.
TABLE 2-1. EQUIPMENT WILL NOT TURN ON WITH AC ADAPTER
SYMPTOM
PROBABLE CAUSE
REMEDY
Unit will not turn on
with AC adapter
supplied.
Adapter defective
Bad connection from
Adapter to equipment power
input.
Defective main PCBA
Check the AC adapter voltage output
(Table 1.1 Specification). If voltage is
low or nonexistent, replace the AC
adapter.
If OK, proceed.
Make sure appropriate AC Adapter is
used.
Check power input connection.
Replace main PCBA

CHAPTER 2 DIAGNOSIS
Ohaus Corporation www.ohaus.com 2-2 ST5000 Bench Top pH Meter Service Manual
TABLE 2-2. EQUIPMENT TOUCH PANEL DOES NOT RESPONCE.
PROBABLE CAUSE
REMEDY
Touch Panel controls
does not respond
Bad touch panel calibration
Lose cable connection.
Re-calibrate Touch Panel (A.4)
Check film cable connection from main
PCBA to LCD screen.
Check film cable connection from touch
panel to LCD screen.
TABLE 2-3 MEASURING RESULTS INCONSISTANT.
PROBABLE CAUSE
REMEDY
End results are not
accurate.
Inconsistent pH reading.
Inconsistent temperature
reading.
Wrong buffer group is used
during calibration
Recalibrate the pH electrode and
temperature electrode.
Use the correct buffer group during
calibration.

CHAPTER 2 DIAGNOSIS
ST5000 Bench Top pH Meter Service Manual 2-3 Ohaus Corporation www.ohaus.com
2.4 PROPER CONNECTION of ELECTRODE WITH METER.
Don‘t bend the cable too much
Check for clean and dry contacts
Use as less adapters as possible
Don‘t extend the cable
Use correct temperature sensor (NTC30kOhm)
2.5 pH ELECTRODE PREPARARTION BEFORE
CALIBRATION OR MEASUREMENT.
First, unpacking an electrode, then:
1. Remove protecting bottle, (turn off the bottle first, then move the upper cap)
2. Open electrolyte filling hole
3. Check if enough electrolyte is in the electrode, or you need to refill the electrolyte.
4. Check that there are no air bubbles behind the junction remove through vertical
shaking
5. Rinse electrode with distilled water
6. Never wipe the membrane with a paper towel (electrostatic charge!)
Carefully dab the electrode dry
Then you can calibrate the electrode and start measurement.
Things to consider when calibrate or measure:
1. Electrolyte level must be higher than in the sample solution or buffer.
Otherwise the sample flows into the reference system -> wrong results 
Approx. 3 cm higher than sample level
2. Stirring
- often not reproducible
- instable signals because of instable diffusion at the diaphragm
- Non-stirred pH results are often more correct than stirred.
2.6 STORAGE of THE pH ELECTRODES.
1. Rinse the electrode with pure water or distilled water.
2. Recap the electrode with the protection bottle or place the electrode in a beaker with
storage solution.
3. Close the filling hole.
Always store in:
3 mol/L potassium chloride (3 M KCl, saturated with AgCl)
Never store the electrode in distilled water or dry!
Otherwise the pH sensitive glass membrane will be affected which shortens the lifetime and the
electrode must be reconditioned before use.

CHAPTER 2 DIAGNOSIS
Ohaus Corporation www.ohaus.com 2-4 ST5000 Bench Top pH Meter Service Manual
2.7 DIAPHRAGM CONTAMINATION ISSUE.
Most of the problems during pH measurements are caused through a contaminated diaphragm,
Symptoms:
Dependancy of the stirrer speed
Drifting result
Shift of offset
Decrease of slope
Contaminated diaphragm = Number one troublemaker!
Diaphragm contamination can occur with:
solutions that contaminate the diaphragm
(e.g. solutions containing proteins, paints, AgS,…)
suspensions, emulsions
highly acidic solutions
strong alkaline solutions
low ionic samples (distilled water, ultrapure water)
solutions with high salt concentration
non-aqueous solutions
Cleaning the diaphragm
blocked with AgCl
-with concentrated ammonia
blocked with Ag2S
-with 8 % thiourea in 0.1 molar HCl
blocked with proteins
-with 5 % pepsin in 0.1 molar HCl
other contaminations
-in ultrasonic bath with water or 0.1 molar HCl
Or just replace with a new one
2.8 RECONDITIONING OF THE DRY GLASS MEMBRANE.
Dry membrane:
Re-conditioning in 0.1 mol/L HCl during 12 hours.
2.9 LIFETIME OF AN ELECTRODE.
The lifetime of an electrode is limited. Apart from maintenance and sample consistency,
one of the reasons is the aging of the membrane.
The aging o the pH sensitive membrane and therefore the decrease of the H+-sensitivity
depends on the temperautre:

CHAPTER 2 DIAGNOSIS
ST5000 Bench Top pH Meter Service Manual 2-5 Ohaus Corporation www.ohaus.com
2.10 SYMPTOMS FOR AN AGED ELECTODE.
Higher membrane resistance
Slow response
Decrease of slope
Increase of offset
Serial number: e.g. 1428001,it is manufactured at the 28th week of 2014.
X
Y
WW
SSS
1 or 2
year
week
001-999