FIELD SERVICE / PARTS MANUAL
Contents
1. 3 1 3 2 Service of Models 310 311 Hanging Pan 3 3 3 3 Service of Series 1200 School 3 3 3 4 Service of Series 1400 and 1500 Harvard Trip 3 4 CHAPTER 4 PARTS LISTS ALM ete EE 4 1 LIST OF TABLES TABLE NO TITLE 1 1 Mass asien 1 2 1 2 Models 310 and 311 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 5 5 5 6 5 3 Seies 1200 Balance Drawing 5 7 5 8 5 4 Series 1400 and 1500 Harvard Trip Balance Drawing2. ASSEMBLY 3051 00 SCREW HOLDING TRIG LOOP Figure 5 1 Typical Triple Beam Drawing 5 3 5 4 CHAPTER 5 DRAWINGS PAN BOW 4521 00 SCALE PAN 4600 00 BALANCE COMPENSATOR KNOB 4517 00 e 1 3 Ps A y 4 Fa BALANCE COMPENSATOR i SPRING 4519 00 BEARING 1008 23 BEARING COVER 1035 03 FRICTION PLATE 1034 00 100g POISE ASSEMBLY 4536 00 200g POISE ASSEMBLY 4537 03 10g POISE ASSEMBLY 4535 00 1g POISE ASSEMBLY 4511 00 MAGNET 6396 00 DAMPER VANE 4516 00 DIAL PLATE 4526 00 TRIG LOOP THREADED ROD 4529 10 Figure 5 2 Models 310 and 311 Balance Drawing 5 5 5 6 CHAPTER 5 DRAWINGS era RED PAN 2743 00 YELLOW PAN men wa Y 2743 01 een x doa k I IRENE ee C 1 NY TAPPING SCREW E 2203 23 POINTER ZERO ADJUST 2719 00 Figure 5 3 Series 1200 Balance Drawing 5 7 5 8 CHAPTER 5 DRAWINGS FRICTION PLATE 1247 0 2 NJ N San a un Cin ae BEARING COVER 1035 03 oy er hee A a i TOP VIEW BEARING SCALE PLATE 1023 00 3045 00 a non em Om AAA OL I lo BALANCE CUP a a LL ES da AN e e AGHE are re ees COMPENSATOR KNOB _ TL 028 KNIFE TU _ TOS 5
3. 5 9 5 10 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 require ments Mustbe free of air currents or drafts from air conditio
4. 1008 23 Agate Bearing 4 1034 00 Friction Plate 2 1035 03 Bearing cover 2 1097 00 Balancing Slug 3 3551 01 Dial Assembly 4511 00 1g Poise Assembly 4512 10 200 g Graduated Beam Insert 4513 10 100 g Graduated Beam Insert 4514 10 10 g Graduated Beam Insert 4515 10 1 g Graduated Beam Insert 4516 00 Damper Vane D 2202 14 2 4519 00 Balance Compensator Spring D 2202 14 4529 10 Threaded Rod 4534 00 Balance Compensator 4535 00 10 g Poise Assembly 4536 00 100 g Poise Assembly 4537 03 200 g Poise Assembly 4561 00 Wrench 4600 00 Pan Without Serial Number 6396 00 Magnet sold in pairs only 9702 00 Pan Support Assembly NOTE Magnet 6396 00 must be magnetized Pricing is per pair 4 3 CHAPTER 4 PARTS LISTS TABLE 4 3 MODEL 1200 SCHOOL BALANCE PARTS LIST PART NO 2743 00 2743 01 DESCRIPTION Red Pan Yellow Pan TABLE 4 4 MODEL 1400 1500 SERIES HARVARD TRIP BALANCE PARTS LIST PART NO 1008 23 1023 10 1034 00 1035 03 1071 01 1097 00 1240 00 1247 00 1316 10 1318 00 1320 00 1322 00 1325 00 3045 00 3225 00 3359 00 DESCRIPTION Agate Bearing 6 Balance Cup 2 L 1107 63 Screw Friction Plate 4 Bearing Cover 5 Stainless Steel Pan Set Balance Slug 4 Pan Model 10 gram Poise Single Beam Friction Plate with Tab 2 200 gram Graduated Insert 10 gram Graduated Insert 10 gram Poise Double Beam Damper Vane Magnet sold in pairs only 2 pai
5. 1200 50 1210 00 1210 50 Capacity g 2000 2000 2000 2000 Readability g Calibrations Beam 10g x 0 5g 10g x 0 5g Mass set 50g to 10 50g x to 10g TABLE 1 5 SERIES 1400 AND 1500 HARVARD TRIP BALANCE SPECIFICATIONS Capacity g 2000 2000 2000 2000 2000 Weigh beam capacity 10g x 0 19 10g x0 1g 109 0 19 10g x 0 1g 10z x 0 010z x readability 200g x 10g 200g x 10g 200g x 10g 28 4 x 0 2g A PATAS Models 1200 00 and 1200 50 do not have a graduated beam however they are sensitve to 0 5 gram CHAPTER 1 INTRODUCTION 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 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 b
6. Li LD FRONT VIEW Figure 5 4 Harvard Trip Balance Drawing 5 9 5 10 MECHANICAL BALANCES P N 79815 01
7. Ohaus Corporation 29 Hanover Road Florham Park NJ OHAUS 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 10 108 Ohaus Corporation 29 Hanover Road Florham Park NJ OHAUS 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 Page No 1 1 O y a 1 1 1 2 Service Facilities tasca 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 He 1 2 1 5 Specifications 1 2 CHAPTER 2 CARE OF MECHANICAL BALANCES 2 1 Care of Balances TA N ARAS 2 1 CHAPTER 3 SERVICING 3 1 Service of Series 700 Triple Beam Balance
8. alance base Never store balance with zero weight Constant oscillation dulls the Knife Edges Causes a jolt when lifted Check calibration and linearity periodically Use known weights calibrated masses CHAPTER 2 CARE OF MECHANICAL BALANCES 2 2 CHAPTER 3 SERVICING 3 1 SERVICE OF SERIES 700 TRIPLE BEAM Refer to Figure 5 1 in Section 5 for identification of parts NOTE Non removable Knife Edges you must replace the Beam A Non Repeatability Problem Damper Vane touching the end of Trig Loop Solution Loosen the screw holding Trig Loop to Base and move it back Problem Bent Damper Vane that is making contact with magnets in Trig Post Assembly Solution Bend Vane with fingers or needle nose pliers hold Beam down when performing this operation or remove the Trig Loop remove the Vane and hammer straight Problem Dull Knives Solution To check Knives hold Beam down Does it return to zero Hold Beam up Does it return to zero If not replace the Beam This may also indicate chipped Knife Edges B Can Not Zero Balance Problem Missing Poise This is the Weight that slides on the Beam Solution Replace new Poise and secure by forcing Check Pin up with a pair of needle nose pliers The 100g Poise has the Check Pin the 500g Poise does not Problem Shot Missing from under Pan Solution Set Zero Adjustment at mid point of travel Set all Poises at zero Unscrew the Balance Pan and place it upside down on the Balan
9. ce Add lead shot or pieces of metal to bring Balance close to zero Transfer shot to Balance Cup and reassemble Balance Pan Problem Chipped Knife Edge or dull worn Bearing notches To check pry off Bearing Covers these will have to be replaced by new ones Remove Friction Plates and lift out the Beam Solution If Knife Edges are chipped or worn replace the Beam If Bearings are worn slide them up and replace with new Bearings NOTE Balance that does not have repeatability is also a symptom of worn bearings C No Beam Movement Problem Twisted Beam or Vane rubbing Solution Refer to Section A Problem Foreign Material on Magnets Solution Remove with adhesive backed tape or remove Trig Loop and clean magnets CHAPTER 3 SERVICING 3 1 SERVICE OF SERIES 700 TRIPLE BEAM Cont No Beam Movement Cont Problem Check Pin Missing Solution Replace NOTE There is a long rod under the Balance thatis held in place by 2 pins Problem Broken Magnet Solution Remove Trig Loop and replace Magnet NOTE Magnets should attract each other in force Problem Rubber stoppers used in shipping at the end of the Beam and under the Pan are still in place Solution Remove both D Beam Graduations need replacing Solution Replace with new Lexan Graduated Strip The old Graduated Strip will peel off When replacing move front Poise completely to the left and line up new Graduated Strip at zero E Zero Adjust Knob Re
10. d piece with an endless screw passing through The horse shoe device must have parallel sides or the endless screw will jam This is your zeroing device Bend with needle nose pliers to make sides parallel NOTE Your balance was adjusted with the red and yellow removable pans that came with your balance Do Not Mix Pans with other balances 3 4 SERVICE OF SERIES 1400 AND 1500 HARVARD TRIP BALANCES Refer to Figure 5 4 in Section 5 for identification of parts Note Non Removable Knife Edges you must replace the Beam A Non Repeatability Problem and Problem Confirmation Technique Dull Knife Edges To check set Balance at zero Hold down one Pan and release Repeat with other Pan If Balance does not return to zero Knife Edges are chipped or worn Solution Return balance to Ohaus for service Problem Bent Damper Vane Solution Bend Damper Vane with fingers or needle nose pliers Note The easy way to observe this is to elevate the Balance with the Rod Support Problem Foreign material on magnets Solution Remove with adhesive backed tape B Can Not Zero Balance Problem Zero Adjust Knob missing Solution Replace with proper Zero Adjust Assembly Note hold Leaf Spring down with a screw driver or ball point pen until flare passes over the Spring Problem Shot missing from Pan Support Cup Solution Unscrew Pan or Fork Assembly and add metal pieces or shot until balance comes to zero Note Make sure all Poises movab
11. le Weights on the Beam are at zero and tare weight is pushed all the way to the left C Pans vs Plates A Pan is the removable sample Platform that is 6 diameter x 3 4 deep Pans on Harvard Trip Balances are matched for an individual Balance and when replacing you will get a matched set Pans are NOT interchangeable between Balances The Pan sits in the Fork of the Balances A Plate is the flat sample holder and is not removable under normal use It screws directly into the Balance Cup CHAPTER 4 PARTS LISTS 4 1 PARTS LISTS This section of the manual contains selected replacement parts which are identified in Figures 5 1 through 5 4 1 In all cases when a part is replaced on any product the product must be thoroughly checked to insure accurate performance to factory specifications 2 Part numbers in the replacement parts lists are only shown for parts which are field serviceable 3 When a part number is preceded by an asterisk refer to the note relative to that part located at the bottom of the page 4 When more than one of each item is used in the manufacture of a product the quantity will be listed in parenthesis following the description 5 Some descriptions are followed by the fastener part number and quantity required Fasteners must be ordered separately 6 Prices and specifications are subject to change without notice 7 See last page in this section for a Glossary of Terms Approximate restorati
12. ning heating ducts open windows people walking by fans etc e 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 Inorderto properly service Mechanical Balances certain testitems 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 10009 2 required 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 Capacity g Readability g CHAPTER 1 INTRODUCTION 1 5 SPECIFICATIONS Cont TABLE 1 3 SERIES 700 TRIPLE BEAM SPECIFICATIONS Capacity g Capacity g with accessory mass set Readability g Calibrations 500g x 100g 100g x 10g TABLE 1 4 SERIES 1200 SCHOOL BALANCE SPECIFICATIONS 1200 00
13. o Adjust Knob missing or Leaf Spring missing Solution Replace with new assembly Note Hold down Leaf Spring until flare on Knob has passed over the spring To perform this operation Beam should be removed from the balance Problem Shot missing from Pan Support assembly Solution Remove hanging assembly and place it upside down on desk or bench Remove screws on Pan Support Assembly and all weights and shot Re hang Pan and with Zero Knob set at mid point Set all parts on the Pan poise at Zero Add or take away shot until Balance returns to zero Then re assemble Note hanging Pan Balances are adjusted with Pans and Balance Serial Numbers matched Mixing up Pans will cause this problem When replacing the removable Pan you will have to go through this operation Problem Dial O Gram balance Dialis out of calibration Solution This is a problem that should be corrected by a trained technician 3 3 SERVICE OF 1200 SERIES SCHOOL BALANCE Refer to Figure 5 3 in Section 5 for identification of parts NOTE Non Removable Knife Edges must replace Beam Problem Beam does not move Solution Check Beam Dampening Device Metal Loop that looks like a paper clip coming out the left side of the Balance Base Bend so it does not touch Beam when not in use CHAPTER 3 SERVICING SERVICE OF SERIES 1200 SCHOOL BALANCE Cont Problem Zero adjust does not move Solution Turn the balance over You will see a black horse shoe shape
14. on fee Triple Beam 750 Series 50 60 Triple Beam 800 Series 75 310 311 Hanging Pan 55 60 Harvard Trip 70 NOTE If further technical information is needed in the United States call Ohaus Aftermarket toll free 1 800 526 0659 between 8 00 a m and 4 00 p m EST An Ohaus factory service technician will be available to provide assistance Outside the U S A please contact Ohaus Corporation 29 Hanover Road Florham Park NJ 07932 USA Tel 201 377 9000 Fax 201 593 0359 CHAPTER 4 PARTS LISTS PART NO 1008 23 1023 10 1034 00 1035 03 1039 02 1093 00 1097 00 1247 00 3045 00 3051 00 3125 10 3126 10 3127 10 3128 00 3134 02 3135 10 3135 11 3225 00 3254 00 3359 00 9704 00 TABLE 4 1 MODEL 700 SERIES PARTS LIST DESCRIPTION Agate Bearing 4 Balance Cup L1107 63 Screw Friction Plate 3 Bearing Cover 4 Pan Model 710 Check Pin 2 Balancing Slug 3 Model 750S Friction Plate with Tab Stainless Steel Scale Plate Model 750 Check Rod Assembly Graduated Beam Insert 10g x 1g Graduated Beam Insert 500g x 100g Graduated Beam Insert 100g x 10g 0 10 gram Poise 0 500 gram Poise 0 100 gram Poise pin 125 from edge 0 100 gram Poise pin 196 from edge Compensator Spring Damper Vane D2202 14 Screws 2 Compensator Knob Tare Beam Assembly CHAPTER 4 PARTS LISTS TABLE 4 2 MODEL 311 CENT O GRAM PARTS LIST PART NO DESCRIPTION
15. placement Hold down Leaf Spring with a small screw driver or ball point pen and screw in until flare has passed over the Spring This is the most common cause of not being able to zero the balance Check to see if the leaf spring is missing F Replacing cracked or broken Balance Cup NOTE This is a frequent occurrence when a balance is dropped and lands on the pan edge Unscrew Balance Pan and remove Counterweights and shot from Balance Cup Remove screw holding Bal ance Cup to Parallel Loop Assembly and remove old Balance Cup Reassemble adding or removing shot to bring Balance to zero 3 2 CHAPTER 3 SERVICING 3 2 SERVICE OF MODELS 310 311 HANGING PAN BALANCE Refer to Figure 5 2 in Section 5 for identification of parts A Non Repeatability Problem Bent Damper Vane Solution Straighten with fingers or needle nose pliers Note Hold down Beam when performing this operation Problem Foreign material on magnets Solution Remove with adhesive backed tape Problem Dull Knife Edges Solution To check set Balance at zero hold down Beam and release Hold Beam up and release If Balance does not return to zero knife edge should be replaced These parts are replaceable in the field but it is not recommended Special tools are required to reassemble End Loop and even though the Knife Edges can be replaced in the field the alignment technique is difficult without extensive training B Can Not Zero Balance Problem Zer
16. rs required Scale Plate 2 Compensator Spring Compensator Knob Agate Bearing Balance Cup Bearing Cover Compensator Assembly Damper Vane Fork Cross Friction Plate Pan Plate Poise CHAPTER 4 PARTS LISTS GLOSSARY OF TERMS The V shaped Bearing that supports the Knife Edge The Plastic Cupthatattachestothe Beam with abolt and receives the Balance Plate Cross or Fork The Stainless Steel cover that holds the Friction Plate in place It must be pried off to check Knife Edges and must be replaced with new product when removed Zero Adjust Knob The Aluminum metal part that is attached to the Beam and moves between the Magnets to slow the Beam movement How does it work The Aluminum Vane is nonferrous and is not attracted to the Permanent Magnet it is however an electrical conductor When itmoves through a magnetic field it sets up a magnetic field opposing the magnetic field of the Permanent Magnets This slows the Beam movement The faster the Beam moves the stronger the magnetic field The speed of the Vane is proportional to the strength of the magnetic field pro duced The support mechanism that holds the Scoop The support mechanism that holds the Balance Pan This is the black hardened metal piece that keeps the Knife Edge in place The removable part of the balance upon which the sample is placed raised edge The non removable part of the balance upon which the sample i
17. s placed flat The Mass or weight that moves along the Beam NOTE On a two Pan Equal Arm Balance the sample is always placed on the left Pan or plate 4 5 CHAPTER 4 PARTS LISTS 4 6 CHAPTER 5 DRAWINGS 5 1 DRAWINGS This section of the manual contains drawings which indicate the field replaceable parts NOTE In all cases where a part is replaced the balance must be thoroughly checked after the replacement is made The balance MUST meet the parameters of all applicable specifi cations in this manual If further technical information is needed inthe United States call Ohaus Aftermarket toll free 1 800 526 0659 between 8 00 a m and 4 00 p m EST An Ohaus factory service technician will be available to provide assistance Outside the U S A please contact Ohaus Corporation 29 Hanover Road Florham Park NJ 07932 USA Tel 201 377 9000 Fax 201 593 0359 CHAPTER 5 DRAWINGS 5 2 CHAPTER 5 DRAWINGS 0 100g POISE 500g POISE BEAM ASSEMBLY 3135 10 3134 02 3266 30 FOR MODELS 710 TO amp 710 TW 710 00 amp 760 W0 COMPENSATOR SPRING 3225 00 BEARING COVER 1035 03 t S S BALANCE PLATE BALANCE CUP 3045 00 1023 00 TRIG LOOP FRICTION PLATE perc ERE m 1034 00 3 without tab 1247 00 with tab BALANCE SLUG L V 1097 00 V ee _ S S _ j MAGNETS IN TRIG LOOP COMPENSATOR KNOB AGATE BEARING DAMPER VANE 1008 23 3254 00 CHECK PIN CHECK
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