Ohaus Mechanical Balances Service manual
Ohaus Corporation
29 Hanover Road
Florham Park, NJ
07932-0900
MECHANICAL BALANCES
FIELD SERVICE / PARTS
MANUAL
SERVICE MANUAL
Mechanical Balances
OHAUS® is the registered trademark of Ohaus Corporation, as are
the following trademarks: CENT-O-GRAM®, CHECK-O-GRAM®,
DEC-O-GRAM®, DIAL-O-GRAM®, PRIMER®, 5-0-5®, AND 10-10®.
Ohaus Corporation
29 Hanover Road
Florham Park, NJ
07932-0900
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 1997 Ohaus Corporation, all rights reserved.
® Registered trademark of Ohaus Corporation.
TABLE OF CONTENTS
CHAPTER 1 INTRODUCTION
1.1 Introduction.............................................................................................1-1
1.2 Service Facilities..................................................................................... 1 -1
1.3 Tools and Test Equipment Required ......................................................1-2
1.3.1 Standard Tools and Test Equipment List........................................1-2
1.4 Test Masses Required............................................................................1-2
1.5 Specifications..........................................................................................1-2
CHAPTER 2 CARE OF MECHANICAL BALANCES
2.1 Care of Balances ....................................................................................2-1
CHAPTER 3 SERVICING
3.1 Service of Series 700 Triple Beam Balance ...........................................3-1
3.2 Service of Models 310/311 Hanging Pan Balance..................................3-3
3.3 Service of Series 1200 School Balance.................................................3-3
3.4 Service of Series 1400 and 1500 Harvard Trip Balances.......................3-4
CHAPTER 4 PARTS LISTS
4.1 Parts Lists ...............................................................................................4-1
Page No.
LIST OF TABLES
TABLE NO. TITLE
1-1 Mass Values......................................................................................1-2
1-2 Models 310 and 311 Specifications...................................................1-2
1-3 Series 700 Triple Beam Specifications..............................................1-3
1-4 Series 1200 School Balance Specifications ......................................1-3
4-1 Model 700 Series Parts List ..............................................................4-2
4-2 Model 311 Cent-O-Gram Parts List...................................................4-3
4-3 Model 1200 School Balance Parts List..............................................4-4
4-4 Model 1400 and 1500 Series Harvard Trip Balance Parts List .........4-4
LIST OF ILLUSTRATIONS
FIGURE NO. TITLE
5-1 Typical Triple Beam Drawing ..................................................... 5-3/5-4
5-2 Models 310 and 311 Balance Drawing....................................... 5-5/5-6
5-3 Seies 1200 Balance Drawing ..................................................... 5-7/5-8
5-4 Series 1400 and 1500 Harvard Trip Balance Drawing ............. 5-9/5-10
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CHAPTER 1 INTRODUCTION
1.1 INTRODUCTION
This manual is not to be considered a service manual for service technicians. This
manual is designed to assist the end user for maintenance and making minor repairs.
This manual contains information needed to perform routine field maintenance and
service on the Mechanical Balances, Models: 310/311 with Hanging pan, Series 700 Triple Beam, Series 1400 and 1500 - Harvard Trip Balance and Series 1200 - School
Balance. The contents of this manual is contained in five chapters and are listed as
follows:
Chapter 1 Introduction - Contains information regarding service facilities, tools,
measuring masses, and specifications.
Chapter 2 Care of Mechanical Balances - Contains information on the care of
mechanical balances.
Chapter 3 Servicing - Contains typical problems and solutions for servicing.
Chapter 4 Parts Lists - Contains a partial parts list for each model or series and
identifies all field replaceable components.
Chapter 5 Drawings - Contains a drawing for each model or series and identifies all
field replaceable components. Each item on the drawings contain part numbers which
can be ordered.
Before servicing the balance, you should be familiar with the Instruction Manual which
is packed with every balance.
1.2 SERVICE FACILITIES
To service Mechanical Balances, the service area should meet the following requirements:
• Must be free of air currents or drafts from air conditioning/heating ducts, open
windows, people walking by, fans, etc.
• Area must be clean and air must not contain excessive dust particles.
• Work surface must be stable and level.
1-1
CHAPTER 1 INTRODUCTION
1.3 TOOLS AND TEST EQUIPMENT REQUIRED
In order to properly service Mechanical Balances, certain test items are required. These
items are listed as follows:
1.3.1 Standard Tools and Test Equipment List
1. Standard Tool Kit.
2. Mass sets up to 2610 grams are required. Ohaus makes various calibration
sets available. Please contact your nearest Ohaus dealer for further details.
1.4 TEST MASSES REQUIRED
The masses required to test the Mechanical Balances must meet or exceed the
requirements of ASTM Class 4 Tolerance. The mass values are listed in Table 1-1.
TABLE 1-1. MASS VALUES
MODEL CAPACITY CALIBRATION MASS PART NUMBER
310 310g 300g 51035-05
311 311g 300g 51035-05
700 Series 2610g 500g 51055-06
1200-00 2000g 1000g (2 required) 51016-06
1210-00 2000g 1000g (2 required) 51016-06
1400 Series 2000g 1000g (2 required) 51016-06
1500 Series 2000g 1000g (2 required) 51016-06
1.5 SPECIFICATIONS
Complete specifications for the Mechanical Balances are listed in Tables 1-2, 1-3, 1-4
and 1-5. When a balance has been serviced, it must meet the specifications listed in
the tables. Before servicing the balance, determine what specifications are not met.
TABLE 1-2. MODELS 310 AND 311 SPECIFICATIONS
Model 310 311
Capacity (g) 310 311
Readability (g) 0.01 0.01
1-2
CHAPTER 1 INTRODUCTION
1.5 SPECIFICATIONS (Cont.)
TABLE 1-3. SERIES 700 TRIPLE BEAM SPECIFICATIONS
Capacity (g) 610
Capacity (g) with accessory mass set 2610
Readability (g) 0.1
Calibrations:
Front beam 10g x 0.1g
Middle beam 500g x 100g
Rear beam 100g x 10g
TABLE 1-4. SERIES 1200 SCHOOL BALANCE SPECIFICATIONS
Model 1200-00 1200-50 1210-00 1210-50
Capacity (g) 2000 2000 2000 2000
Readability (g) 0.5* 0.5* 0.5 0.5
Calibrations:
Beam ------ ------ 10g x 0.5g 10g x 0.5g
Mass set 50g to 1g ------ 50g x to 10g ------
TABLE 1-5. SERIES 1400 AND 1500 HARVARD TRIP BALANCE SPECIFICATIONS
Model 1450-SD 1550-SD 1560-SD 1510-DO 1454-SD
Capacity (g) 2000 2000 2000 2000 2000
Weigh beam capacity 10g x 0.1g 10g x 0.1g 10g x 0.1g 10g x 0.1g 1oz x 0.01oz
x readability 200g x 10g 200g x 10g 200g x 10g 28.4 x 0.2g
Tare range ------- ------ 225g ------ ------
* Models 1200-00 and 1200-50 do not have a graduated beam, however, they are
sensitve to 0.5 gram.
1-3
CHAPTER 1 INTRODUCTION
1-4
CHAPTER 2 CARE OF MECHANICAL BALANCES
2.1 CARE OF BALANCES
Mechanical balances are precision instruments and as such, they should be handled,
treated and cleaned with care. This section briefly outlines some of the preventive
handling and storing methods to be applied to mechanical balances.
2.1.1. Keep them clean
• Pans - clean with soap and water, dry thoroughly.
• Beams, graduated strip - a commercially available spray cleaner.
• Knife edges - compressed air or an air syringe - no oils or lubricants.
• Magnets - avoid ferrous (magnetic) material contact - clean with adhesive
backed tape.
2.1.2. Always secure beam when handling
• Prevent side -to- side Beam movement - damages and dulls Knife Edges.
• Prevent excessive up-down beam movement - causes premature wear of Knife
Edges.
• Never carry Balance by the Beam. Hold beam tightly in place with one hand and
carry Balance by placing second hand under the balance base.
2.1.3 Never store balance with zero weight
• Constant oscillation dulls the Knife Edges.
• Causes a jolt when lifted.
2.1.4 Check calibration and linearity periodically
• Use known weights/calibrated masses.
2-1
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