11 Description

The < > Model 140A (Figure 1-1) is a general purpose plug-in oscilloscope. The deflection amplifiers are contained within the plug-in units, which operate directly into the cathode-ray tube. Thus the characteristics of the oscilloscope are dependent upon the plug-ins used. Presently available plug-ins make possible high-sensitivity, wide bandwidth, and single, dual, or four-trace measurements, in combination with normal, single, or delayed sweeps. Double-size plug-ins also are...

112 Cathoderay Tube Warranty

The cathode-ray tube supplied with the Model 140A is guaranteed against electrical failure for one year from the date of sale by the Hewlett-Packard Company. The cathode-ray tube warranty is illustrated in Figure 1-2. A warranty sheet for your use is included in the appendix of this manual. The cathode ray tube supplied in your Hewlett-Packard Oscilloscope and replacement cathode ray tubes purchased from fy , are guaranteed against electrical failure for one year from the date of sale by...

21 Incoming Inspection

Upon receipt of the Model 140A, check the contents of the carton and inspect the instrument for any obvious damage received in shipment. If damage is evident, file a claim with the carrier. Refer to the warranty sheet at the rear of this manual for additional information. Keep the packing material until an operational check has been completed. 2-3. OPERATIONAL CHECK. Refer to Section V (Paragraph 5-3) for a performance check to verify that operation is within...

210 Cooling

The Model 140A uses a forced-air cooling system to maintain reasonable operating temperatures within the cabinet. The air intake and filter are located on the rear of the instrument. When installing the Model 140A, choose a location that provides at least three inches of clearance around rear and sides of instrument. 2-14. The filter should be cleaned periodically to ensure proper cooling. After cleaning, the air filter, located on the rear of the instrument, should be coated with a...

215 Instrument Mounting

The Model 140A is shipped from the factory as a bench instrument with the tilt stand, feet, and plastic trim in place. The top and bottom cabinet covers can be removed, giving complete accessibility to all components and adjustments. Sufficient space should be allowed around the cabinet for adequate circulation air. 2-19. Prepare the cabinet for rack mounting as illustrated in Figure 2-1. All necessary hardware is in the shipping carton with the instrument. After preparation, lift the...

220 Installation Of Amber Filter

An amber filter ( Stock No. 120A-83A) is supplied with oscilloscopes which have a CRT with type P7 phosphor. This filter improves the visibility of displays such as single-shot or very low frequency phenomena. The filter improves the long persistency characteristics of the trace when making visual observations of this type of display. To install the filter a. Remove front panel CRT bezel. b. Set filter into bezel, aligning larger rectangular slots in edge of filter with guide metal posts...

24 Power Requirements

The Model 140A requires a power source of 115 or 230 volts 10 , single phase, 50 to 60 cps, which can deliver approximately 300 watts. Be sure to set the 115-230 volt switch for the line voltage to be used. The power supplies may be damaged if this switch is set to the wrong position. 2-7. If the instrument is to be operated from a 230-volt source, set the switch on the rear of the instrument to 230. The line fuse, located behind the rear panel, is accessible by removing the bottom cover,...

312 Plugin Units

Insert vertical amplifier (or other unit desired to produce vertical deflection) into the lower compartment, and lock in place. Insert a time base plug-in (or amplifier) into upper compartment, and lock in place. For double-sized plug-ins, remove the dividing shield, insert plug-in, and lock. For proper operation, make sure that the shield is in place when using standard size plug-ins. 3-14. GAIN. Because of differences in cathode-ray tube sensitivities, it will usually be...

33 Controls And Indicators

Figure 3-1 identifies the front panel controls, indicators, and terminals, and provides a short description of their functions. 3-6. BEAM FINDER OPERATION. Frequently the CRT trace can be driven off the CRT screen by excessive DC input levels or by misadjustment of position or balance controls on the plug-ins. When the BEAM FINDER switch is depressed, the beam is confined to the screen of the CRT. If the trace is centered with the position and or balance control when the BEAM FINDER is...

516 Geometry Adjustment

W VIO W RED VIO BLU W GRN W RED W BLU VIO Figure 5-2. Adjustment and Component Locations, Bottom View b. Connect a 400-kc signal from the Audio Oscillator to the vertical INPUT of the amplifier plug-in. c. Adjust vertical and horizontal controls to obtain a pattern 8 cm high. d. Adjust Geometry R343 to obtain the straightest possible edges on the rectangular pattern.

518 Troubleshooting

The series regulator transistors are located on the fan assembly. Each is easily replaced by removing the two screws and Table 5-3. Condensed Adjustment Procedure Table 5-3. Condensed Adjustment Procedure Measure -lOOv (Violet) -12.6v (White Violet) +100v (White Red) DC VTVM 100 1 Divider Voltmeter Calibrator a. Calibrate Divider - Voltmeter combination. b. Set INTENSITY to 10 o'clock. R312 until spot is just extinguished. FOCUS and ASTIGMATISM for sharp spot. a. TRIGGER...

53 Performance Check

Install a single large plug-in or two small plugin units in the Model 140A (vertical plug-in in the lower compartment, horizontal in the upper compartment) . b. Set POWER ON AMPLIFIER coupling (if present) . AC POSITION controls Centered c. If a time base plug-in is being used, d. A trace should be on screen. If necessary, turn INTENSITY control clockwise. e. Remove trace from screen with POSITION controls. Depress BEAM FINDER. The trace should appear on screen. f. The INTENSITY control...

56 Adjustments

The following paragraphs (5-11 through 5-17) give a complete adjustment procedure for the Model 140A Oscilloscope. A condensed procedure is given in Table 5-3. If difficulty is encountered in making any adjustment, refer to Paragraph 5-18 for troubleshooting procedures. 5-8. EQUIPMENT NEEDED FOR ADJUSTMENTS. Test equipment recommended for the adjustment procedure is listed in Table 5-1. Similar instruments having the listed characteristics may be substituted. 5-9. LOCATION OF ADJUSTMENTS....

61 Introduction

This section contains information for ordering replacement parts. Table 6-1 lists parts in alpha-numerical order of their reference designators and indicates the description and ( stock number of each part, together with any applicable notes. Table 6-2 lists parts in alpha-numerical order of their 0 stock numbers and provides the following information on each part a. Description of the part (see list of abbreviations below). b. Typical manufacturer of the part in a five-digit code see list...

Contents

IV PRINCIPLES OF OPERATION (Cont'd) 4-18. High-Voltage Power Supply 4-3 4-24. Trace Align 4-3 5-3. Performance Check 5-1 5-11. Adjustment of Low-Voltage 5-13. Adjustment of High-Voltage Supply 5-1 5-14. Intensity Limit Adjustment 5-2 5-15. Astigmatism Adjustment 5-2 5-16. Geometry Adjustment 5-2 5-17. Calibrator Adjustment 5-3 5-19. Low-Voltage Power Supplies 5-3 5-26. High-Voltage Supply 5-3 5-31. Repair and Replacement 5-7 5-32. Air Filter 5-7 5-34. Removal of Cathode-Ray Tube 5-7 5-37. Fan...

414 Calibrator

The schematic diagram of the calibrator is given in Figure 5-5. This circuit consists of three parts a tunnel diode square wave generator, a transistor switch, and a calibration network. 4-16. 6.3 volts AC is applied through R201 to tunnel diode CR201, which generates a square wave at line frequency. Transistor switch Q201 is off during the time of the positive half-cycle of the square wave (when the voltage at the base is close to zero), and the collector voltage is thus at a level set...

List Of Tables

Plug-Ins for Model 140A Oscilloscope 1-2 5-1. Equipment Required for Tests and 5-2. Low-Voltage Adjustments 5-1 5-3. Condensed Adjustment Procedure . . . 5-4 5-4. Troubleshooting the Low-Voltage Supply 5-5 5-5. Troubleshooting High-Voltage Supply, No 5-6. Troubleshooting High-Voltage Supply, Incorrect Voltage 5-8 6-1. Reference Designation Index 6-3 6-2. Replaceable Parts 6-10 Accepts horizontal plug-ins, Models 1420 to 1424 or, if desired, amplifier plug-ins,...

46 Lowvoltage Power Supply

The low-voltage power supply includes an independent supply (-100 volts) and three dependent supplies (+250, +100 and -12.6 volts). The -100 volt supply is a reference for the +100 volt supply. A breakdown diode serves as the reference for the -12.6 volt supply. The +250 volt supply is obtained by stacking a 150-volt supply on top of the +100 volt supply. 4-8. Figure 4-2 is a simplified block diagram of a regulated power supply. The series regulator acts Figure 4-2. Regulated Power Supply...

424 Trace Align

Trace-aligning coil L302 is located around the CRT near its screen. Adjustment of Trace Align R350A B varies the magnitude and direction of current through the coil, which has the effect of rotating the trace. In this way the trace is brought into alignment with the CRT graticule. Table 5-1. Equipment Required for Tests and Adjustments Table 5-1. Equipment Required for Tests and Adjustments Calibrator check High Voltage Adjustment Calibrator Adjustment Outputs of lv and lOv p-p -300v DC...

531 Repair And Replacement

Inspect the air filter at the rear of the instrument and clean it before it becomes clogged enough to restrict the flow of cooling air. To clean, remove the filter from the instrument and wash it thoroughly in warm water and detergent. Dry thoroughly and coat with a filter adhesive such as Filter Coat No. 3 from Research Products Inc. This adhesive is available from heating supply stores or from your Hewlett-Packard Engineering Representative. 5-35. It is recommended that a face mask or...

513 Adjustment Of Highvoltage Supply

Connect a Model 11044A 100 1 Voltage Divider to the DC probe of a Model 410B Voltmeter. b. Set Voltmeter to 3-volt -DC range. c. Set the Voltmeter Calibrator for -300 volts DC output, and connect divider tip to the output. Figure 5-1. Component Locations, Top View Figure 5-1. Component Locations, Top View d. Set the gain adjustment of the Model 410B (located at the rear of the instrument) for a reading of exactly 3 volts. e. Set the Voltmeter to the 30-volt range, and measure the high...

41 General

Figure 4-1 is a simplified block diagram of the Model 140A Oscilloscope. Three major circuits are included in the main unit of the oscilloscope a low-voltage power supply, an amplitude-and-time calibrator, and a high-voltage power supply for the cathode-ray tube. The vertical and horizontal plugins are not part of the main unit, and operate directly into the CRT. 4-3. LOW-VOLTAGE POWER SUPPLY. The low-voltage power supply uses 115 230 volt single-phase power from the line, and generates...

418 Highvoltage Power Supply

Figure 4-3 is a block diagram of the high voltage power supply. The output of a regulated transistor oscillator is stepped up in voltage and applied to a series of high-voltage rectifiers. The positive output of the voltage doubler is connected to the post-accelerator of the CRT. The negative output voltages are used in the gun assembly of the CRT and its associated controls. The Z-AXIS INPUT can be used to apply an intensity modulating signal to the cathode of the CRT. 4-20. Figure 5-8...

List Of Illustrations

Model 140A Oscilloscope with Model 1400A Amplifier and Model 1420A 1-2. Cathode-Ray Tube Warranty 1-3 2-1. Rack Mounting Procedure 2-0 3-1. Model 140A Controls 3-2 4-1. Model 140A Block Diagram 4-1 4-2. Regulated Power Supply Block Diagram 4-2 4-3. High-Voltage Power Supply Block 5-1. Component Locations, Top View 5-2 5-2. Adjustment and Component Locations Bottom View 5-3 5-3. Removal of High-Voltage Deck Assembly 5-8 5-4. Component Locations on High-Voltage 5-5....

17 Associated Equipment

Tube Oscilloscope

Some of the plug-ins available for the Model 140A Oscilloscope are listed in Table 1-2. The Model 140A normally is used with an amplifier plug-in in the lower compartment and a sweep plugin in the upper compartment. The plug-in in the lower compartment produces vertical deflection, and the plug-in in the upper compartment produces horizontal deflection. All Model 1400-series plug-ins can be used with the Model 140A Oscilloscope. Plug-in model numbers are grouped according to function...

Oscilloscope

Copyright HEWLETT-PACKARD COMPANY 1963 1501 PAGE MILL ROAD, PALO ALTO. CALIFORNIA, U.S.A. 01638-1 Printed JULY 1963 I GENERAL INFORMATION 1-1 1-1. 1-5. 1-7. Associated Equipment 1-1 1-10. Instrument Identification 1-2 1-12. Cathode-Ray Tube Warranty . . 1-2 2-1. Incoming Inspection 2-1 2-4. Power Requirements 2-1 2-6. 230-Volt Operation 2-1 2-8. Three Conductor Power Cable 2-1 2-10. 2-11. Ventilation Requirements . 2-1 2-13. Air Filter 2-1 2-15. Instrument Mounting 2-1 2-16. Modular Cabinet 2-1...