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HP 400D Operating And Servicing Manual
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HP 400D Operating And Servicing Manual

Vacuum tube voltmeter
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VACUUM TUBE VOLTMETER
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OPfRATING AND SfRVICING MANUAl

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Summary of Contents for HP 400D

  • Page 1 VACUUM TUBE VOLTMETER � OPfRATING AND SfRVICING MANUAl...
  • Page 3 OPERATING SERVICING MANUAL MODELS 400D/H/L VACUUM TUBE VOLTMETERS Model400H Model400D Model400L Serial 27971 and above Serial 6526 and above Serial 6516 and above 1956 Copyright HEWLETT-PACKARD COMPANY 275 PAGE Mn.L R�D, PALOALTO, CALIFORNIA, U.S.A. 400DHL002-1/5-59...
  • Page 5 , 20 cps to I mc. CALmRATIO N: MODELS Reads rms value of sine w ave. Voltage in­ 400D and 400H: dication proportio nal to average value of ap­ plied wave. Linear voltage scales 0 to 3.0 and 0 to 0;...
  • Page 6 SPECifiCATIONS (CONT'D) MODEL 400D/H/L AMPLIFIER: Output terminals are provided so voltmeter can be used to amplify small signals or monitor waveforms under test with an oscilloscope. Output approximately 0, 15 volt rms on all ranges with full-scale meter deUee - tion.
  • Page 7 Con •• n •• SECTION I GENERAL DESCRIPTION 1 - 1 General Description I - 2 Damage Transit Power Line Voltage Power Cable Accessories OPERATING INSTRUCTIONS SECTION 2 - 1 Controls and Terminals 2 - 2 Operation THEORY OF OPERATION SECTION General .
  • Page 8 ONE SIDE OF POWER LINE IS ALSO GROUNDED REPRO UT I ON Both the black binding posts and the instrument case will be connected to the power system NEMA A void short circuits ground when the instrument is used with the standard receptacle.

  • Page 9: General Description

    Sect. I Page 1 SECTION I GENERAL DESCRIPTION GENERAL DESCRIPTION DAMAGE IN TRANSIT This vacuum tube voltmeter is an accurate and upon initial inspection this instrument is found sensitive average-responding rms calibrated volt­ to be damaged in any way, refer to CLAIM FOR meter which will measure ac voltages from 0.001 DAMAGE IN SHIPMENT for the necessary in­...
  • Page 10 Sect. Page 2 Model AC-60A Line Matching Transformer - Model 452A Capacitive voltage Divider Division ratio: 600 ohm unbalanced output, for measurements on ±3% Accuracy: l/lf.1f balanced lines. Input Capacity: 151J1lf, ± Maximum volt- age rating: 6 0 cps 25 kv Terminating Resistance: 1 me 20 kv...
  • Page 11 OPERATING INSTRUCTIONS CONTROLS AND TERM1NALS OPERATION NOTE When the Mcxiel 400D or 400H is turned off the meter This toggle switch closes the primary circuit of the power transformer. With the switch ON, the pointer should indicate zero. it does not, refer red pilot lamp will glow.
  • Page 12 Pa�e Sect. 11 - 1 5 lOOK - S-7 IMPEDANCE OHMS Figure ModeI400n/H/L Impedance Correction Graph 2-1.
  • Page 13 Sect. Il Page 3 EFFECT OF HARMONICS ON MODEL 400D/H/L VOLTAGE MEASUREMENTS TABLE 2-1. True Value Indicated Input Voltage Characteristics 400D/H/L Model RMS Value Fundamental 100.5 Fundamental +10% 2nd harmonic 100-102 Fundamental +20% 2nd harmonic 100-110 Fundamental +50% 2nd harmonic 100.5...
  • Page 14 Sect. Page 4 amplifier open-circuit output is approximately EXAMPLES: . 15 volt rms on all ranges. The response of the Actual amplifier is flat across the band from 1 0 cycles to Range Meter Meter 4 mc. The impedance, looking into the OUTPUT Switch Scale Indicates...

  • Page 15: Theory Of Operation

    Sect. Page SECTION '" THEORY OF OPERATION the r m s value of a sine-wave voltage applied at GENERAL INPUT. The circuit of this vollmeler includes a two-step The circuit of the voltmeter is discussed in greater voltage divider in the input. a stabiiized broadband amplifier, a ret.:Hfier and meter circuit, and a detail in the following paragraphs.
  • Page 16 Sect. Page 2 SlA of the range switch sets up connections in such Amplifier - Between the grids of V2 and V5 the amplifier a manner that the input voltage Is applied directly yields a net gain of approximately 55 to 60 db over to the grid of cathode follower VI without being re­...
  • Page 17 CYCLE HALF NEGATIVE CYCLE CI1 A R2 l +--- • ---+ ---+ FROM VI " ' R29B R28B R29A R28A RlS C SO -L -1 1 Figure 3-2. Model 400D/H/L Direction of Current Flow through RectUier Meter Bridge Partial Schematic...
  • Page 18 Sect. Page 4 diode CR 1 is non-conducting, as capacitor C32 dis­ (± 10%) or a 230 volt (± 10%) 50/1000 cps source. charges, current flows through the meter and diode The primary circuit is fused. When switch 82 is CR2 to the generator.

  • Page 19: Maintenance

    15 minutes with the cabinet in place. The power supply should be checked after replaCing V6, V7� VB, or V9 in the power supply. MODELS 400D AND 400H Turn warmed-up instrument off and allow about Heater voltage must be checked and adjusted after two minutes for internal capacitors to discharge.
  • Page 20 Sect, Page +250V ( REG) FI __ R66 CIB C39 CI7 INPUT SHIELD REMOVED MP-S-340 Figure 4-1. Model400n/H/L View of Left Side Instrument Case removed...
  • Page 21 Sect. Page 3 TABLE 4-1, TUBE RE PLACEMENT Tube Function Circuit Adjustment paragraph 4 - 7C 6CB6 Cathode Follower DC Heater Voltage, 6CB6 Amplifier Rapid Performance Check, paragraph 4-6 6CB6 2nd Amplifier 6CB6 3rd Amplifier 6CB6 4th Amplifier Rapid Performance Check, paragraph 4-6 6AX5 High Voltage Rectifier...
  • Page 22 Sect. IV Page 4 (SIA- D) (C7 THRU CIG) (R12 THRU R19) (RIOA-B, RIIA-D) MP-S-169 Figure 4-2. Model400D/H/L View Right Side Instrument Case Removed...
  • Page 23 MODEL 400L ONL pleting th test procedure. :F'oi' example, e entire t h e instrument being checked is Model basic calibration can checked and adjusted at any 400D/H, complete step A and skip to step C. time without making any other adjustments.
  • Page 24 METER THAT IS CONNECTED TO A COMMON GROUND WITH THE VTVM UNDER TEST WHEN THESE HEATER VOLTAGES MEASURING - A SHORl' a Model 400D or 400H vtvm is involved, fol­ cmCUIT Slight readjustment of WILL RESULT. low the zero adjustment procedure paragraph 4-2.
  • Page 25 :1:2% of full scale for a included to verify the instrument response and to 400D voltmeter or ±l% of full scale for a 400H or restore proper operation in case the original ad­ 400L voltmeter. The test voltage should be between justment is altered.
  • Page 26 Sect. Page S 0. 03, 0 Change input signal to 6. 4 mc and set amplitude 12) Check frequency respOnse on . 1, and 0. 3 to "SET LEVEL". volt ranges. Establish a cps "SET LEVEL" for each range and then check the response at 4 mc. The reading on the vtvm under test should not an error greater than ±...
  • Page 27 Sect. Page 9 1) Connect a 400 cps sine wave signal to the INPUT 9) Change the input signal to 4 mc and set the input of the vtvm under test. Adjust signal level for a amplitude to the "reference level" established in reading of 0 .
  • Page 28 Sect. Page 10 2) When trouble has been localized to a particular the regulator output is within these limits, the power supply probably is functioning properly, and section, it is recommended that tube substitution be the remainder of the circuit should tried before any other tests are made.
  • Page 29 Page 11 Sect. TABLE 4-2. TROUBLE SHOOTING CHART (CONT'D) Possible Cause and/or Remedy Symptom Trouble in power supply (see paragraph 4-9). Meter. indication is equally erratic on all ranges. Tubes V2, V3, V4 and/or defective. Crystal diode and/or CR2 defective. Capacitor C2 may be shorted or leaky.
  • Page 30 Sect. Page 12 TABLE 4-2. TROUBLE SHOOTING CHART (CONT'D) Possible Cause and/or Remedy Symptom instrument seems to be equally microphonic on Microphonics (Cont' d. ) the 0. 3 volt range with 0 . 3 volt input, change instrument is less microphonic on the 0.
  • Page 31 Sect. IV Page 13 POWER SUPPLY TROUBLE Screen voltages for V2, V3, V4 and V5 shOuld be ±IO volts. LOCALIZATION +135 volts, If trouble is localized to the power-supply section, 2) Reduce line voltage to 103 volts. Again measure the following checks will be helpful in trouble shooting. V2 through V5 dc plate and screen voltages.
  • Page 32 When checking tube V5, avoid Sborting crystal diodes CRl and. CR2 to ground. With power turned on, the diodes '" will 5, SI VOLTS (range) switch, their terminals are shorted to ground. burn Figure 4-3. Model 400D/H/L Servicing Block Diagram...
  • Page 35 Sect. V Page SECTION V TABLE OF REPLACEABLE PARTS N O T R e a d i l y a v a i l a b l e s t a n d a r d - c o m p o n e n t s h a v e b e e n u s e d i n t h i s i n s t r u m e n t , w h e n e v e r p o s s i b l e .
  • Page 36 Sect. Page 2 T A B L E O F R E P L A C E A B L E P A R T S cmcurr STOCK • • &. REF. DESCRIPTION, MFR MFR. DESIGNATION Capacitor: fixed, electrolytIc, 18-42HP 4 sections, 20Jlflsect.
  • Page 37 Sect. Page 3 T A B L E O F R E P L A C E A B L E P A R T S cmcurr STOCK " & REF. DESCRIPTION, MFR. MFR. DESIGNATION S ... me as CHI Capacitor: fixed, mica, 14-47...
  • Page 38 Sect. V Page 4 T A B L E OF R E P L A C E A B L E P A R T S cmCUIT � STOCK • • DESCRIPTION, MFR MFR. DESIGNATION REF. & CH l, 2 G-29B-5 Rectifier, silicon diode special �...
  • Page 39 Resistor: fixed, composition, 23-10K _10%. 1/2 10, 000 ohms, Resistor: fixed, composition, 23-470 470 ohms, ±10%, 1/2 RIO, 11 Resistor: fixed, wirewound, 400D-71 (400D ONLy) Resistor: fixed, wirewound, 400H-71 (400H/L ONLY) Resistor: fixed, composition, 23-27 27 ohms, ::dO%, 1/2 Resistor:...
  • Page 40 Sect. T A B L E O F R E P L A C E A B L E P A R T S r&J cmcurr STOCK REF. DESCRIPTION, & M DESIGNATION • • Resistor: fixed, wirewound 4000-268 R28 8 Resistor: fixed, wirewound...
  • Page 41 Sect. V Page T A B L E O F R E P L A C E A B L E P A R T S cmCUIT � STOCK REF. DESCRIPTION, MFR . • & MFR. DESIGNATION Same as Same as R2! Resistor: fixed, composition, 24-3300...
  • Page 42 Sect. Page 8 T A B L E R E P L A C E A B L E P A R T S rIj; CIRCUIT STOCK DESCRIPTION, MFR • • & MFR. DESIGNATION Resistor: variable, wirewound, 210-114 4 ohms, :j,20%, 1 Same as R9 Resistor:...
  • Page 43 T A B L E O F R E P L A C E A BL E P A R T S CIRCUIT � STOCK • & REF. DESCRIPTION, MFR. MFR. DESIGNATION Range Switch Assembly (4000 ONLY) 400D-19W Range Sw itch Assembly (400H/L ONLY) 400H-19w Switch, Toggle: SPST 310-11 Rectifier, metallic 212-101...
  • Page 44 LIST OF CODE LETTERS USED IN TABLE OF REPLACEABLE PARTS TO DESIGNATE THE MANUFACTURERS CODE CODE � MANUFACTURER ADDRESS LmER MANUFACTURER ADDRESS Aeroyox Corp. New Bedford, Mon. Hgmmerlqnd Mf\!, Co., Inc:. New York I, N. Y. Chicogo 18, Ill. Allen-Brut/ley Co. IndultriQI Condennr Corp.
  • Page 45 CLAIM FOR DAMAGE IN SHIPMENT The instrument should be tested as soon as it is received. If il fails to operate properly. or is damaged in any way, a claim should be filed with the carrier. A full report of the damage should be obtained by the claim agent, and this report should be forwarded to us.

  • Page 47: Manual Changes

    MANUAL CHANGES MODEL 400D VACUUM TUBE VOLTMETER ERRATA: Sect. 11 Page 4-Subparagraph "C"9 Amplifier: Delete all of the information to the end of the section . Replace with the following: AMPLIFIER With full scale meter deflection, the amplifier open circuit...

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