HP 8559A DPM Accuracy

MODEL 8559A

SERVICE

DPM Accuracy

The following is a guide to troubleshooting poor DPM accuracy. Further information is included following the circuit descriptions of the indicated assemblies.

Check + 14.5Vsupply on the Frequency Control Assembly A7 (A7TP3).

Perform and verify Frequency Display Adjustment (Paragraph 5-30).

Verify Tuning Accuracy (Paragraph 4-12).

Check Marker Board Assembly A8.

Check frequency accuracy of first and second local oscillators.

First LO: DPM inaccuracies become worse as the higher bands are selected (i.e., increases in harmonic mixing mode).

Second LO: DPM inaccuracies are constant in all bands.

Contents

Page WARRANTY HP LIMITATION 0F WARRANTY EXCLUSIVE REMEDIES ASSISTANCE HEWLETT PACKARD OPERATION AND SERVICE MANUAL CONTENTS GENERAL INFORMATION Introduction Description Manual Organization Safety Considerations VIII SERVICE REPLACEABLE PARTS Test Equipment General Information Troubleshooting Hints Page Page ADAPTER SPECTRUM ANALYZER OVERLAY KIT SECTION GENERAL INFORMATION 1-11.SAFETY CONSIDERATIONS 1-13.INSTRUMENTS COVERED BY MANUAL 1-14. Serial Numbers SERIAL NUMBER 1-16.Manual Updating Supplement frequency) Noise Sidebands: Video Filter AMPLITUDESPECIFICATIONS AMPLITUDE RANGE Maximum lnput (without damage) Levels Total Power: DC: AC (<I00 Hz): 7.1 Vrms Peak Pulse Power: Gain Compression Display Fidelity Log Incremental Accuracy: Log Maximum CumulativeError: Linear Accuracy: RESIDUAL RESPONSES Page SUPPLEMENTAL CHARACTERISTICS FREQUENCY CHARACTERISTICS AMPLITUDE CHARACTERISTICS FREQUENCY ACCURACY AMPLITUDE RANGE AND ACCURACY Third Order IntermodulationDistortion Relative Disortion Signal Identifier SWEEP CHARACTERISTICS SUPPLEMENTALCHARACTERISTICS AUX C 21.4 MHz IF OUTPUT ATTEN (i.e dBm 1-26.EQUIPMENT REQUIRED BUT NOT SUP PLIED 1-27.Display Mainframe 1.30.Extender Cable Assembly 1-32.EQUIPMENT AND ACCESSORIES AVAILABLE 1-41.SERVICE ACCESSORIES 1-43.RECOMMENDEDTEST EQUIPMENT Page ItemDescription HP Part Number Recommended Critical Specifications Model Use Page Instrument Page INSTALLATION AND OPERATION VERIFICATION 2-12.To install side stops: Use flathead machine screws to install side stops as shown in Figure Reinstall side covers on mainframe Place label on front panel of spectrum analyzer (upper 2-13.To remove side stops: 2-15.To install a graticule overlay: 4.Slide bezel back into place to retain overlay and filter 2-17.Operating Environment Temperature 40°C Temperature: - 40°C to +75°C Altitude: <7620 meters (25,000 feet) 2-24.Packaging Original Packaging Seal the shipping container securely H P Part No Page SECTION Ill OPERATION 3-18.Amplitude. The amplitude group consists of: REFERENCE LEVEL dBm INPUT ATTEN REF LEVEL FINE REF LEVEL CAL 10 dB/DIV - 1 dB/DIV - LIN (Amplitude Scale) 3-20.OPERATING PRECAUTIONS With an adjustment tool, adjust the FOCUS control as necessary to make the characters on the CRT as clear as possible 3-30.Display Adjustments - HP 180-Series Display Mainframe 3.Adjust FOCUS and ASTIG controls for the smallest round dot possible Adjust VERTICAL POSN to align the CRT trace with the bottom graticule line 250 MHz CAL OUTPUT Page PERFORMANCE TESTS TESTS 4-11.FREQUENCY SPAN ACCURACY SPECIFICATION: DESCRIPTION: EQUIPMENT: Comb Generator Comb Generator FREQSPAIWDIV SIG IDENT ................................................................. OFF COMB FREQUENCY - MHz INTERPOLATION AMPLITUDE- 1 MHz OUTPUTAMPLITUDE 4-11. FREQUENCY SPAN ACCURACY (Cont'd) Page Set function generator frequency to 200 kHz 0.5%) div Using the procedure of NOTE in step 13 CombGenerator RF Plug-In Frequency Counter 10-dBAttenuator Adapter, Type N (f) to N (f) TUNING Amplitudescale Page Comb Generator 4-13.RESIDUAL FM (Cont'd) COMB FREQUENCY- MHz Full clockwise 5.Set RESOLUTION BW to 10 kHz and SWEEP TIME/DIV to 0.1 sec CombGenerator 4-14.NOISE SIDEBANDS(Cont'd) COMB FREQUENCY - MHz INTERPOLATION AMPLITUDE - 1 MHz OUTPUT AMPLITUDE (30 4-15.RESOLUTION BANDWIDTH ACCURACY 0.707 (voltage ratio) = X div/7.1 div Signal Generator Extender Cable Assembly Adapter, Type SMB (f) to BNC (f) AmplitudeScale Calculate and record resolution bandwidth at Min. ActualMax 3.90 MHz 345 kHz 115kHz Set equipment controlsas follows: Spectrum Analyzer: FREQUENCYBANDGHz X.010GHz OkHz Page 4-15.RESOLUTION BANDWlDTH ACCURACY (Cont'd) kHz Adapter, SMB (f) to BNC (f) 4-16.RESOLUTION BANDWIDTH SELECTIVITY(Cont'd) Set equipment controls as follows: >O.OlOGHz lkHz 12 o'clock z - 3dBm Page kHz Page ...................................... HP 181T/TR 4-17. AVERAGE NOISE LEVEL (Cont'd) REF LEVEL FINE BL CLIP Page ...................................... HP 181T/TR 909A 4-18.RESIDUAL RESPONSES(Cont'd) Terminate INPUT 5(M2 connector with 50-ohmtermination GHz dBm Increase TUNING control setting in 4-19.FREQUENCY RESPONSE (*dB RF Plug-in Power Meter Power Sensor Attenuator, 20-dB CrystalDetector ....... 0.100GHz MARKERS ............ OFF SWEEP MODE ............ EXT Maximumdivisions Minimumdivisions 8th graticule line divisions Remove Page Page Page Frequency Response, 18- 21 GHz Page 4-20. GAlN COMPRESSION Powersensor Power Splitter 20-dBAttenuator Adapter, Type N (f) to N (f) (Cont'd) 4-20.GAIN COMPRESSION(Cont'd) 4.21.BANDWIDTH SWITCHING (AMPLITUDE VARIATION) INPUT AlTEN Page 10-dBAttenuztor FREQUENCY BAND GHz COUNTER MODE dB Maximum Error per 10-dBStep dB Maximum Positive Corrected Deviation dB Maximum Negative Corrected Deviation dB Maximum Cumulative Step Error 4-23.REFERENCE LEVEL ACCURACY 10-dBAttenuator Step Attenuator (1 dB/step) Step Attenuator (10 dB/step) 4-23. REFERENCE LEVEL ACCURACY (Cont'd) Step Accuracy in Log Mode 4-23.REFERENCE LEVEL ACCURACY(Cont'd) REFERENCE Deviation from Step Accuracy in Linear Mode 4-23. REFERENCELEVEL ACCURACY (Cont'd) LEVEL Setting (dBm) :Calibration)**(dB) 0(Ref.) 0.030GHz 50kHz FunctionGenerator 50 MHz Universal Counter BNCTee 4-24.SWEEP TIME ACCURACY (Cont'd) FREQSPAWDIV AmplitudeScale RANGE Frequency DCOFFSETLEVEL and 4-24. SWEEP TIME ACCURACY (Cont'd) A 50 MHz Input SENSITIVITY (B) B 10 MHz Input W E E P Sweep Time 4-25.CALIBRATOR OUTPUT ACCURACY 4-26.DISPLAY FIDELITY (2 required) Log Display Accuracy 4-26.DISPLAY FIDELITY (Cont'd) (in 4-26. DISPLAY FIDELITY (Cont'd) +24 Para No Test Description Min Results MinActualMax 4.13.Residual FM Noise Sidebands Resolution Bandwidth Accuracy Min.ActualMax Residual Responses Bandwidth Switching (Amplitude Variation) Input Attenuator Accuracy Reference Level Variation Min Max Sweep Time Accuracy Calibrator Output Accuracy Page ADJUSTMENTS 5-13. RELATED ADJUSTMENTS 5-15.FACTORY SELECTED COMPONENTS 8559A Page Page Page or Repaired Basis of Selection CAPACITORS (PF) RESISTORS Value (a) (a) Ohms * I % HP Part (a) ( a ) Extender Cable RESOLUTION BW REFERENCE LEVEL Amplitude Scale SWEEP TIME/DIV Page 5-18.CALIBRATED SWEEP TIME ADJUSTMENT A9 Schematic .......................................... H P 5300B/5302A H P 5300B/5302A .............................................. H P 1.Set equipment controls as follows: >0.010 GHz 1msec FREE RUN TI . A to B Check time interval for each SWEEP TIME/DIV control setting listed in Table 5-19.LOG AMPLIFIER LOG AND LINEAR ADJUSTMENTS Step Attenuator (10-dB/step) Step Attenuator (1-dB/step) Adapter, Type N (m) to BNC (f) Adapter, SMC (m) to BNC (f) FREQSPAN/DIV Set spectrum analyzer Amplitude Scale control to 10 dB/DIV Repeat steps 8 and 9 until no further adjustment is necessary Repeat steps 11 and 12 until no further adjustment is necessary -30 dB potentiometer A14R69 for DVM reading ( t 1 mV) -10 dB potentiometer A14R39 for DVM reading ( t 1 mV) Example ( +5 mV offset): +805 +800 +708 +703 20.Disconnect AlOWl from step attenuator and reconnect to A5J2 - 50 dBm Set signal generator controls as follows: approx. - 5 dBm FREQUENCY Log Gain Page 5-20. 1-dBOFFSETADJUSTMENT Page 5-21.BANDWIDTH FILTER ADJUSTMENTS A9, A11, and A13 Schematics Adapter, Type N (m) to BNC (f) Crystal Short (3 required) Crystal Short (3 required) HP 1250-0780See Figure 5-6HP FREQUENCYBAND Set FREQ SPAN/DIV to 10 kHz and RESOLUTION BW t o 10 kHz Center the signal with FINE TUNING control Using REF LEVEL FINE control, place signal peak at 7.1 divisions (10 Set FREQ SPAN/DIV to 20 kHz and RESOLUTION BW to 30 kHz Page Page 35.Set AmplitudeScale switch to 1 dB/DIV and jumper A9TP6 to A9TP8 36.Short A11TP3, A1 lTP6, A13TP3, and A13TP6 to ground 37.Set RESOLUTION BW to 100 kHz and FREQ SPAN/DIV to 200 kHz Page 5-22.3.dB BANDWIDTH ADJUSTMENTS !EE ................................................. 0.01-3GHz ........................................................ OFF 5-22. 3-dBBANDWIDTH ADJUSTMENTS(Cont'd) Connect signal generator as shown in Figure can Set H P 8559A RESOLUTION BW to 13.Adjust REF LEVEL FINE to place signal at 7.1 divisions Record the counter frequency BANDWIDTH 5-23.RF GAlN ADJUSTMENT Digitalvoltmeter PowerSensor with 51.1 ohm resistor TestCable,BNC(m)toBananaPlug Page Page 5-24. STEP GAlN ADJUSTMENTS Step Attenuator (1 dB/Step) Step Attenuator (10 dB/Step) Digital Voltmeter Adapter, BNC (m) to SMC (m) Cable, BNC (m) to Banana Plug VIDEO FILTER Page 5-25.FIRST CONVERTER ADJUSTMENTS FrequencyCounter Digital Voltmeter Comb Generator Cable, BNC (m) to Banana Plug ALTIF AlternateIF First LO Shift Check MHz FM Driver Sensitivity and Delay Compensation Adjustment RES BW FREQUENCY BAND GHz TRIGGER Repeat steps 25 and 26 to achieve the best span linearity Repeat step 30 for a frequency of approximately 2.5 GHz Set comb generator for 100-MHzcomb teeth Adjust front-panelTUNING control for 0.10 GHz indication on FREQUENCY display Set FREQ SPAWDIV to 2 MHz MHz (MO) 1 MHz 5-26.SECOND CONVERTER ADJUSTMENTS @.@a@ Frequency Counter Function Generator Test Cable, BNC (m) to SMB (f) Adapter, BNC (f) to Alligator Clips 853A 5-26. SECOND CONVERTER ADJUSTMENTS(Cont'd) Depress front-panelALT IF pushbutton. Turn SIG IDENT off Note Second LO frequency on frequency counter RESBW RESBW Band1 (.01-3) MHz Page 5-27.THIRD CONVERTER ADJUSTMENTS Sweep Oscillator 20 dB Attenuator 10dBAttenuator Extender Cable Assembly 5-27.THIRD CONVERTER ADJUSTMENTS(Cont'd) 3.Adjust AlOL12 LO ADJ for frequency counter indication of 300.00 MHz +0.1 MHz Second IF BandpassFilter Alignment 4.Disconnect blue cable AlOWl at second converter output connector A5J2 8.Connect test cable or soldered cable to 8569B spectrum analyzer input 9.Set 8569B spectrum analyzer controls as follows: Page 5-28.FREQUENCY RESPONSE ADJUSTMENTS A3, A4, AS, A6, and A12 Schematics L-----------4 517) 5-16 5-28.FREQUENCY RESPONSE ADJUSTMENTS(Cont'd) DESCRIPTION Sweep Oscillator RF Plug-In(.01- 2.4 GHz) RF Plug-In(2 - 22 GHz) Synchronizer Power Sensor (.Ol - 18 GHz) ALTIF REF Adjust Tuning Voltage Circuit GAIN and OFFSET controls to Adjust RF 28.Change spectrum analyzer AmplitudeScale to 1 dB/DI 32.Change synchronizer POLARITY to + 34.Adjust sweep oscillator for swept output from 6 to 9 GHz ~ 2 L01-3 2(6-9 (3-9 5(6-15 3 to 9 GHz Adjustment 9 to 15 GHz Adjustment 6 to 16 GHz Adjustment 57.Change spectrum analyzer Amplitude Scale to 1 dB/DIV Adjust A12R71 59.Total deviation of trace from 6 to 15 GHz should not exceed 4.2 dB 12.1to 21 GHz Adjustment FrequencyCounter Power Sensor TIME/DIV TRIGGER 5-29.CAL OUTPUT AND REF LEVEL CAL ADJUSTMENTS(Cont'd) Adapter, BNC (f) to Alligator Clips 5-30.FREQUENCY DISPLAY ADJUSTMENTS(Cont'd) REPLACEABLE PARTS REFERENCE DESIGNATIONS ABBREVIATIONS Page Multiple 1o Page Page Page Page Page MANUAL BACKDATING CHANGES Page 1-3: Table 1-1. HP 85596 Specifications (1 of 4) i s <95% R.H Pages 4-10and 4-11: Paragraph 4-13.Residual RI MOTE Page 4-63: Table 4-18. Performance Test Record (2 of 4) 2320A & Below -Pages 5-11through 5-13: Paragraph 5-17.Power Supply Checks and Adjustments 5-17. POWER SUPPLY CHECKS AND ADJUSTMENTS(SERIAL PREFIX 2236A) GHz 5-17.POWER SUPPLY CHECKS AND ADJUSTMENTS(SERIALPREFIX 2236A)(Cont'd) Connect digital voltmeter to A9TP6 8.Connect digital voltmeter to A8TP2 VO. Set H P 8559A controls as follows: 5msec SINGLE Pages 5-17 through 5-23: Pages through Paragraph 5-19, Log Amplifier and Linear Adjustments 2208A REFERENCE: A14 and A15 Schematics DESCRIPTION: EQUIPMENT: HP 8640B 377my) 5-19.LOG AMPLIFIER LOG AND LINEAR ADJUSTMENT(SERIAL PREFIX 22O8A) (Cont'd) Set the step attenuator to the positions shown in Table each 15.Readjust A14R2if necessary to meet the limits in Table LIN Select A14R16* to obtain an output in step 17 within REFERENCE Page Adapter, Type N Male to BNC Female BNC Cable, 6-Inch Crystal Short (3 required) TUNING FREQSPAN/DIV SWEEPTIME/DIV Page CTR 5-21.BANDWIDTHFILTER ADJUSTMENTS(SERIAL PREFIX 1909A)(Cont'd) kHz maximum Scale kHz Page 5-22.3 dB BANDWIDTH ADJUSTMENTS(SERIAL PREFIX 1909A) dB 5-22.3 dB BANDWIDTH ADJUSTMENTS(SERIAL PREFIX 1909A)(Cont'd) between 24) peak Hz AlOWl A5J2 Paragraph 5-25. First Converter Adjustrents 5-25.FIRST CONVERTER ADJUSTMENTS(SERIAL PREFIX 2236A) YTO 5-25. FIRST CONVERTER ADJUSTMENTS(SERIAL PREFIX 2236A)(Cont'd) AlternateIF First LO Shift Check ALT IF 1 (.Ol-3) (6.000 REF LEVEL dBm 1 MHz Page Page 6-8: 6-8: Figure 6-1, Mechanical Chassis Parts 6-1 item ( 3 ) , GUSSET ( 3 ) GUIDE 8-23/8-24: Meter Al Heter Assembly A1 Page Page Page Page Page Page BLOCK YTO NOTE l i s t Figure 8-21. 2nd Converter, Component Locations A6 YIG-TUNED .OSClLLATOR (FIRST LO: Pages 8-67through 8-81/8-82:FBEQOEWCY COIlTROL ASSEHBLY A7 Table 8-4.Frequency Control Assembly A7, Replaceable Parts WIRE Figure 8-28.Frequency Control Asserbly A7, Component Locations (-1 C8 Figure 8-29. Frequency Control Assembly 67 Figure 8-29. Frequency Control Assembly A7, Schematic Diagram (1 of 2) (COG~'~) Figure 8-29. Frequency Control Assembly A7, Schematic Diagrar (2 of 2) A7 Page Page Reference HP Part FREQUENCYCONTROL Page Page Page Page Table 8-5. Harker Assembly 88, Replaceable Parts 88 A8R A8 R Figure 8-32, Harker As-bly A8, Component Locations A8 (I) R88 Figure 8-33. Marker Assembly AS, Schematic Diagram (2 of 2) AS ( E l MARKER 10+ 5 V POWER SUPPLY SUPPLY Pages 8-97 through 8-115/8-116:WEEP GEIlERATOR/BIWI[IYIDM C O m O L ASSEHBLY A9 C O m O L ASSEHBLY Table 8-6. Sweep Generator/Bandwidth Control Assembly A9, Replaceable Parts CER POLYE N-CHAN A9 Page Desianation Number Page Page Page SWEEP GENERATOR/BANDWIDTH CONTROL SWEEP GENERATORIBANDWIDTH CONTROL IRETRACE OUT BUFFER AMPLIFIER I TRIGGER SWITCH 2ZW) Page Page /-Pages 8-117through 8-127/8-128:THIRD CONVERIEB ASSEUBLY A10 Table 8-7. Third Converter Assembly A10, Replaceable Parts tlME list time Figure 8-13.Third Converter Assembly A10, Component Locations 8 A Figure 8-44.Third Converter Assembly A10, Schematic Diagram "4 THIRD CONVERTER Q POWER SUPPLIES Pages 8-129through 8-141/8-142:BANDWIDTH FILTER w0. 1 ASSEUBLY A11 w0 Table 8-8:Bandwidth F i l t e r No. 1 Assembly All, Replaceable Parts Figure 8-55.Bandwidth F i l t e r No @FIRST LC POLE GAIIY ASSJ9lBLY D e l e t e Page Page Page Page Page HP Part Designation Number Part I Reference HP Part Designation Number Description- Mfr Part Number A14 LOG AMPLIFIER Page Page Pages 8-191 and 8-199/8-200: MOTHERBOARD ASSEMBLY A16 Table 8-1 4. Motherboard Assembly A1 6, Replaceable Parts A1 6 Figure 8-76. Motherboard Assembly A16, Camponent Locations A16 MOTHERBOARD Page SECTION Vlll SERVICE 8-12. Printed Circuit Board Edge Connector Contact Cleaning MATERIALS: Lint-freecloth or equivalent (HP Part Number 9310-0039,Check Digit 3) Solution of 80% electronics-gradeisopropyl alcohol and 20% water Static-freework station Page (946) SYMBOLS USED IN SCHEMATIC AND BLOCK DIAGRAMS BASIC LOGIC SYMBOLS SYMBOLS USED I N SCHEMATIC AND BLOCK DIAGRAMS Page 8559A REFERENCE LEVEL FINE BL CLIP ALT IF THE HP 8559A SPECTRUM ANALYZER THEORY OF OPERATION General Information RF Section RF Attenuator First Mixer IF the Third Converter Harmonic Mixing F,, - NFL, = F,, (for plus modes) Signal Identifier IF Section Bandwidth Filters Step Gain Amplifier Logarithmic Amplifier TROUBLESHOOTING HINTS Residual FM DPM Accuracy Page Page DIGITAL PANEL METER ASSEMBLY Al, CIRCUIT DESCRIPTION DPM Display Assembly A1A1 DPM Driver Assembly A1A2 -4V 15V supply to +6.2V to the analog IC, U2 Display Interface (E) DIGITAL PANEL METER ASSEMBLY Al, TROUBLESHOOTING Display digits freeze intermittently: Least Significant Digit (LSD) dithers: The same segment in each digit does not light: AlA2U4 failure Page Page DPM DRIVER ASSEMBLY A1A1 DPM DISPLAY ASSEMBLY Page Page FRONT SWITCH ASSEMBLY A2, CIRCU!T DESCRIPTION Page Page (1) 22.Removal of Rotor Assemblies: Remove Frequency Span Rotor (14) with associated parts (9 23.Disassembly of Lock: CLEANING AND INSPECTION OF FRONT SWITCH ASSEMBLY 1 . Assembly of Lock: Lightly grease Locking Shaft (3) (1) (5) Inspect Attenuator Drive Rotor (8). Roll Pins (12) Clean contact fingers on all rotors using 3.Installation of Front Switch Board Assembly A2Al: Do not overtighten screws and studs into Front Switch Diecast(1) Tighten Stud (53) and 4.Assembly of RESOLUTION BW switch: i.Install Retainer Clip (21) on Bandwidth Shaft (55) (54) Inspect Ref Level Fine Assembly (30, 31 o.Use a new tiewrap to attach Ref Level Fine connecting wires to Standoff (62) 6.Installation of RF Input Attenuator A3: 7.Installation of Front Panel: Remove the front panel knobs Page INSTALLATION OF FRONT SWITCH ASSEMBLY INTO HP 8559A CHASSIS FACTORY PRESET SHAFT ASSEMBLIES Page Page Page Page Page A2A1W1 RIBBON CABLE ASSEMBLY FANOUT RIBBON CABLE ASSEMBLY A2A1W2 Page Page Page Page RF SECTION CIRCUIT DESCRIPTIONS INPUT ATTENUATOR ASSEMBLY A3, CIRCUIT DESCRIPTION FIRST MIXER ASSEMBLY A4, CIRCUIT DESCRIPTION F INPUT A'ITEN Verify that the Second Converter Assembly A5 supply voltages are correct Second LO Frequency: GHz Second LO Fails to Oscillate: Second Converter BandpassShape: YIG-TUNEDOSCILLATORASSEMBLY A6, CIRCUIT DESCRIPTION rnA YIG-TUNEDOSCILLATORASSEMBLY A6, TROUBLESHOOTING Power Holes: Residual FM: Reference HP Part Desianation Number Page Mfr 8-16 Page Page HOUSING A5A2 SECOND CONVERTER FILTER ASSEMBLY Page A ~ ~ R S T Page Page FREQUENCY CONTROL ASSEMBLY A7, CIRCUIT DESCRIPTION A2 TunelFull Span Voltage (B) YTO Main Coil Tune Driver (D) FMlMainCoil Sweep Switch (A) YTO Main Coil Fixed Driver (F) Alternate IF Driver (YTO) (C) YTO Main Coil Filter (E) Voltage Regulators (H) (I) (K) FREQUENCY CONTROL ASSEMBLY A7, TROUBLESHOOTING Page 8-26 wire from the COARSE TUNE control (A2R1), and attach the battery's negative R2 Page Page Page Page Page > tsv FREQUENCY CONTROL ASSEMBLY Page Page MARKER ASSEMBLY A8, CIRCUIT DESCRIPTION Marker Generator (F) DPM Driver (D) Second LO Driver (E) ALT IF SIG IDENT Auto Scan Time (AST) Drivers (C) Scan Attenuator (B) Auto Scan Time (AST) Accuracy: Residual FM: Page Page Page Page Page Page MARKER ASSEMBLY b92 Page Page SWEEP GENERATORIBANDWIDTHCONTROL ASSEMBLY A9, CIRCUIT DESCRIPTION Sweep Generator R44 +14V,reverse biasing reset-diodeCR2 (block I) AMPL l F l E R 0.5Y SW l TCH AMPL l F l E R Single Sweep Triggering and Abort Manual Sweep (A2R4) Current Source (F) Xtal Resolution Bandwidth Control (B) LC Resolution BandwidthControl (A) parallel Video Filter Sweep Attenuator (0) (<1 Sweep Offset Page Page Page Page Page Reference HP Part Desianation Number OENERATORIBANDWI DTH CONTROL SWEEP GENERATOR/BANDWIDTH CONTROL ASSEMBLY Q "L Page Page THIRD CONVERTER ASSEMBLY A10, CIRCUIT DESCRIPTION 321.4 MHz Amplifier (A) 321.4 MHz BandpassFilter (C) 300 MHz Oscillator (D) Double Balanced Mixer (E) IF Preamplifier (F) Flatness Compensation Amplifier (H) Non-LinearCurrentSource (G) Band Conversion Loss CompensatingAmplifier (I) 35 MHz CalibrationOscillator (B) 300 MHz Oscillatoroff F~equency: Most common failures are C16, C17, and C18 35 MHz Oscillator off Frequency: Most common failures are C45 and L21 Page Page DescriptionMfr Part Number Page Page Page A10 THIRD CONVERTER ASSEMBLY Page BANDWIDTH FILTERS No. 1 and No. 2 ASSEMBLIES A l l and A13, CIRCUIT DESCRIPTION all 10 dB Input Buffer Amplifier (B) rnA (RJ R Q lOdB INPUT BUFFER First Xtal Pole (D) First LC Pole (C) MHz Unity Gain Buffer Amplifier (E) mA) 21.4 MHz Second Xtal Pole (G) (G) Second LC Pole (F) Output Buffer Amplifier (H) mA Page Page Page Page Page Page Page STEP GAIN ASSEMBLY A12, CIRCUIT DESCRIPTION Step Gain Amplifiers (E) (F) (G) TestINorm Switch 0-12dBControl(H) 21.4 MHz BandpassFilter (I) Band Select Decoder (A) Band Tilt (C) Band Offset (D) Mixer Diode Bias (B) (K) Page Page Page Page A12 STEP Page Page Page BANDWIDTH FILTER No. 2 ASSEMBLY A13 Page Page Page Page Page Page Page Page LOG AMPLIFIER ASSEMBLY A14, CIRCUIT DESCRIPTION AmplifierStages(Istthrough7th) (A) (C) (D) (E) (F) (G) (H) Log Mode of Operation Gain (dB) = 20LOG(1 + R52/RT) Linear Mode of Operation Gain Control Lines (B) R24 1 Log Mode Temperature-ControlledVariable-GainAmplifier(J) Detector (K) Buffer Amplifier (L) Gain = 1 + RllO/R116 1 + 619/619 Log Offset (M) IFG5 TemperatureCompensationPower Supply (I) Page Page Page Page Page Page Page Page VERTICAL DRlVlNGlBLANKlNG ASSEMBLY A15, CIRCUIT DESCRIPTION Preamplifier (A) Beamfinder -5.5V Temperature CompensatingSupply (B) Vertical Driver (E) Sweep Ramp HighlLowLimit Comparator (C) VerticallBaseline Comparator (D) Blanking Driver (F) SWEEP RAMP H I / L O L I M I T Penlift Driver (G) Q4 VR2 Sweep Indicator Driver (H) VERTICAL DRlVERlBLANKlNG ASSEMBLY A15, TROUBLESHOOTING Page Page A15 VERTICA L DRIVERIBLANKIN G A15 VERTICAL DRIVERJBLANKING ASSEMBLY (-1 GND Page Page Page A16 MOTHERBOARD ASSEMBLY 8 ""pT