I INTRODUCTION AND SPECIFICATIONS................................................................ 1-1 1-1. introduction .............................................................................................. 1-1 1-5. Electrical Specifications.......................................................................... 1-1 1-6. Environmental Specifications................................................................... 1-2 1-7. Mechanical Specifications .......................................................................... 1-3 1-8. General Specifications............................................................................... 1-3 II OPERATING INSTRUCTIONS.................................................................................... 2-1 2-1. Introduction ............................................................................................. 2-1 2-4. Operating Features. . .................................................................................. 2-1 2-6. Controls, Terminals and Indicators ........................................ 2-1 2-8. Input Power Requirements ..................................................... 2-1 2-10. Preliminary Operation ............................................................................... 2-1 2-12, AC Line Connections................................................................. 2-1 2-14. Sense Connections....................................................................... 2-1 2-18. Current Limit Operation............................................................. 2-5 2-20. Overload Protection..................................................................... 2-5 2-23. Mechanical Zero Adjustment..................................................... 2-5 2-25.. Operation as a Voltage Calibrator............................................................. 2-5 2-27. Applications .............................................................................................. 2-6 2-29. Operation as a Differential Voltmeter...................................... 2-6 2-31. Operation as a 10 ppm Source................................................... 2-6 III THEORY OF OPERATION.......................................................................................... 3-1 3-1. Introduction................................................................................................ 3-1 3-3. Block Diagram Analysis........................................................................... 3-1 3-12. Circuit Analysis.......................................................................................... 3-3 3-13. +15 Volt Reference and Auxiliary Supplies............................ 3-3 3-16. Chopper-Stabilized Amplifier..................................................... 3-3 3-20. Series Regulator............................................................................ 3-3 3-23. Controlled Current Limiter........................................................ 3-4 3-27. Negative Voltage Limiter............................................................. 3-4 3-29. Sink Supply and Crowbar.......................................................... 3-4 3-34. Control Circuit........................................................................... 3-5 3-38. High Voltage Power Supply....................................................... 3-6 3-40. Meter Circuit............................................................................... 3-6 3-42. Beta String.................................................................................... 3-6 IV MAINTENANCE .......................................................................................................................4-1 4-i. Introduction ............ .......................................................................4-i 4-3. Service information ..............................................................................................4-1 4-6. Test Equipment. ..................................................................................................4-1 4-8. General Maintenance .........................................................................................4-1 4-9, Maintenance Access................................................................. . 4-1 4-13. Adjustment Locations ..........................................................................4-3 4-15. Cleaning...................................................................................................4-4 4“!S. 1 15/230 Volt Conversion.....................................................................4-5 4-20. Fuse Replacement ....................... .......................................................4-5 4-22. Lamp Replacement. ................................................................. . 4-5 4-24. Performance Tests..................................................................................- 4-6 4-26. Line Regulation. ...................................................................................4-6 4-28. Load Regulation...................................................................................4-6 4-30, Ripple ....................................................................................................4-7 4-32. Output Voltage Accuracy....................................................................4-8 4-36. Troubleshooting ...................................................................................................4-8 4-39. Test Point Resistance Check................................................................4-8 4-41. Standby Test.........................................................................................4-8 4-43. Auxiliary Supply Voltages..................................................................4-9 4-45. Power-On Test.....................................................................................440 4-47. Chopper Amplifier ................................................................................4-11 4-49. Series Regulator ...................................................................................4-11 4-51. Controlled Current Limiter ..................................................................4-12 4-53. Crowbar..................................................................................................4-12 4-55. High Voltage Power Supply. ...................... 4-12 4-57. Beta String ............................................................................... . 4-13 4-59. Pane! Meter ...........................................................................................4-13 4-61. Model 341A Calibration .....................................................................................4-14 4-63. Preliminary Operations.......................... 4-14 4-64. Reference Voltage Adjustment. ..........................................................4-14 4-65. Zero Output Adjustments .....................................................................4-14 4-66. Beta String Linearity Adjustments .................. 4-14 4-67. Range Adjustments . ............................................................................4-14 4-68. Calibration Verification .......................................................................4-15 4-70. Model 343A Preliminary Calibration.................................................................4-15 4-72. Preliminary Operations .......................................................................'4-15 4-73. Reference Voltage Adjustment ................................................. : 4-16 4-74. Zero Output Adjustments.....................................................................4-16 4-75. Beta String Linearity Adjustments.....................................................4-16 4-76, Temperature Stabilization..................................................................4-17 4-77. Model 343A Final Calibration .........................................................................4-17 4-79. Zero Output Adjustments....................................................................4-17 4-80. Beta String Linearity Adjustments.....................................................4-17 4-83. Range Adjustments...............................................................................4-19 4-84, Calibration Verifications ...................................................................4-20 V LIST OF REPLACEABLE PARTS ......................................................................................5-1 5-1. Introduction ........................................................................................... . 5-1 5-3. Column Description..............................................................................................5-1. 5-5. How To Obtain Parts ............................................................................................5-2 5-8. List of Abbreviations .........................................................................................5-2 5-9. Serial Number Effectivity ...................................................................................5-45 7 GENERAL INFORMATION................................................................................. · ?-l 8 SCHEMATIC DIAGRAMS...................................................................................................8-1