Racal Instruments 9901, Maintenance Manual

Page 1: ...LOQICAL ACHIEVEIWNT TO DACAL DANA INSTRUMENTS LTD UX3BSB The Electronics Group Racal Dana Instruments Limited Duke Street Windsor Berks England Prepared by Central Handbooks Department Racal Group Ser...

Page 2: ...e sufficiently high to endanger life Covers are NOT to be removed except by persons qualified and authorised to do so and these persons should always take extreme care once the covers have been remove...

Page 3: ...m s nostrils 5 Take a deep breath 6 Cover the victim s mouth with yours and blow watching his chest rise Note Blow forcefully into adults but gently into children 7 Move your face away to allow victim...

Page 4: ...WOH 6201 Universal Counter Timer 9901...

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Page 6: ...f Controls 2 6 Indicators 2 9 Rear Panel Items 2 9 CHAPTER 3 PRINCIPLES OF OPERATION The CDI Chip 3 1 Basic Frequency Meter 3 1 General Circuit Functions 3 2 Dynamic Display System 3 2 Self Check 3 3...

Page 7: ...ime and Reset Generator 4 7 Display Time Circuit 4 7 Reset Pulse 4 7 Manual Reset 4 8 External Reset 4 8 Segment Check 4 8 Frequency Standard 4 8 Standard Oscillator Assembly 19 0834 4 8 Optional Osci...

Page 8: ...tting Optional Frequency Standard Unit 5 14 Fig No IN TEXT ILLUSTRATIONS Page A1 Data Sequence Diagram Tech Spec 3 1 Basic Frequency Meter 3 1 3 2 Period Measurement 3 3 3 3 Time Interval Measurement...

Page 9: ...mponent Layout Display Assembly Fig 1 Parts List 1 Display Assembly Circuit and Layout Oscillator PCB Assembly Fig 2 Parts List 2 c5sci I lator PCB Assembly Parts List 3 Chassis Front and Rear Panel A...

Page 10: ...V liSaWWi4i S l ifLSI JJ a...

Page 11: ...available to give data output in parallel format for printers etc or lEC ASCII bus compatible format Options The ten data output states are as follows the timing Is shown below States Facility 1 fo 8...

Page 12: ...quency Period and Ratio measurement and automatically unlatched in all other modes Overflow Indicator Gate indicator Display Time A asurement Check Segment Check Reset LED ill uminated when overflow o...

Page 13: ...DC to 50 MHz direct AC or DC Gate Times Manual 1 ms to 100s in decade steps Automatic Gate times up to Is are selected automatically to avoid overspill Designed hysteresis avoids undesirable range cha...

Page 14: ...Start and Stop signals For trigger error see page Tech Spec 4 1 count trigger error frequency standard accuracy A 10 ms dead time is automatically Included when contact operation is selected TIME INTE...

Page 15: ...TOTALIZING Input Channel Channel A DC to 10 MHz Maximum Rate 1 events per second Pulse Width 50 ns minimum at trigger points Prescaling Events can be prescaled in decade multiples n from 1 to 10 Reads...

Page 16: ...l levels Refer to Table 1 on page 7 Function and timebase data Schmitt trigger outputs from both channels Inputs 15 POWER REQUIREMENTS Supply Voltage Ranges a c Reset and print hold Also refer to Opt...

Page 17: ...UENCY STANDARD 9442 Frequency 5MHz Ageing Rate 3 parts in 10 day after 3 months continuous operation Warm up Time Better than 2 parts in 10 within 6 minutes Temperature Better than 3 parts in 10 per C...

Page 18: ...8 Auto J Not Used 9 c Function K N Z Time Base 10 b Information L 7 Information 11 See Table 2 M X J See Table 3 12 Ro N Not Used 13 Hold Reset P Schmitt B 1 See 14 Not Used R Schmitt A J NOTE 1 NOTES...

Page 19: ...ncy 1 1 1 Average Period 0 1 1 Totalize A 0 1 0 n Ratio A T 1 1 0 T 1 single line or double not averaged line 0 0 1 T l single line or double averaged line 1 0 1 Time Base Selection Data Output A3 Tim...

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Page 21: ...Pm4lU2 i M AJJlltfc AMSJ...

Page 22: ...e steps a c ord c coupled c Ratio measurement d Time Interval single or double line with manual or electrical start stop signals trigger slope selection and choice of pulse or contact timing control e...

Page 23: ...Chip FREQUENCY STANDARD 1 7 A discrete component 5 MHz oscillator is fitted in the basic versions of the instrument but at customer s option a high stability fast warm up oscillator unit from the Rac...

Page 24: ...to Pulse _n_ 3 Connect the unknown signal to the A input socket 4 If counting is not satisfactory adjust the SENSITIVITY control anti clockwise towards the 10 mV setting until a stable reading is obta...

Page 25: ...ORMAL switch to NORMAL 3 Connect the unknown signal to the A input socket 4 Select the number of periods to be timed by depressing the relevant Range n push button A greater number of periods gives in...

Page 26: ...epetition rate of the pulses under measurement must not be synchronous with the frequency standard in use Time Interval Operation 2 8 1 Set the POWER switch to ON 2 Set the following controls a Functi...

Page 27: ...ccurring with random timing to be counted over a chosen period A counter time base in Totalize mode is generally designed to reset to either 0 or 9 in either case a rounding off of the count occurs to...

Page 28: ...ches to select the required trigger edge polarities 2 Connect the signal to be totalized to socket A and the electrical timing signals if used to socket B 3 Press the Range push button w ich will prov...

Page 29: ...a number of events the resolution is increased iii FREQ A Provides frequency measurement of the A channel input with readout in kHz AUTO and MANUAL Modes With the MAN manual switch depressed the requi...

Page 30: ...ge for start of time interval time interval average and totalize measurements Applies to the B channel only Selects the required stop trigger edge polarity on time interval time interval average and t...

Page 31: ...ounce OPERATE is normal setting CHECK provides a 1 MHz readout of the internal reference frequency for self check of counting and display circuits Segment Check To check all LED segments in the displa...

Page 32: ...cted A 1 MHz reference signal derived from the frequency standard in use is available at this BNC socket The facilities provided by the 28 way edge connector are listed in Table 1 in the Technical Spe...

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Page 34: ...ta for display In the 9901 these functions are carried out in the integrated circuit IC2 which achieves large scale integration using the collector diffusion isolation principle For convenience IC2 wi...

Page 35: ...cimal point selection and external reset are provided by means of discrete circuits e The power system operates from a c mains feeding 5V and 5V rectifiers and stabilizing circuits and 2V supply to th...

Page 36: ...gnal generates a selection of gate waveforms one of which is selected by depressing the appropriate Range n push button The chosen gating waveform is applied to the main gate to control the number of...

Page 37: ...ed by depressing an appropriate Range push button These clock pulses are then coupled to the signal input of the main gate and are totalled in the counter decades during the interval between the Start...

Page 38: ...agram The successive Start and Stop pulses open and close Gate A allowing 10 MHz clock pulses to pass to Gate B during each gate open period Gate B is held open by the time base for the selected time...

Page 39: ...nput and fed via the main gate to the counter A waveform from the time base decades derived from the B Input is selected to gate the A channel signal by depressing an appropriate Range n push button S...

Page 40: ...decade by depressing the relevant n push button This scaled output is coupled to the signal input of the main gate 3 15 A command level from the START push button opens the main gate and allows Count...

Page 41: ...rnal Hold 3 17 If when used with external circuitry it is required to extend the cycle time the external hold signal logic 0 at pin 6 of the data connector must be applied before the end of the gate o...

Page 42: ...The store outputs are enabled in turn for approximately 100 ps by a 10 kHz reference signal derived from the frequency standard 3 21 The b c d data is fed to a 7 segment decoder IC17 which offers the...

Page 43: ...a b and c The time base n units are also selected by a 3 line system identified as lines x y and z The inverse of the logic used in the CDI Chip is available at the rear panel data output connector Th...

Page 44: ...tion of each control as described in Chapter 2 FUNCTION AND RANGE SWITCHING Switch Selection 4 4 In the circuit diagram Fig 4 at the back of the book the Function and Range push button banks SI and S2...

Page 45: ...y pressing the FREQ AUTO button the open collector resistor R53 of IC13e is disconnected allowing IC2 4 to float TABLE 4 Function Information Function Code a b c Frequency 1 1 1 Average Period 0 1 1 T...

Page 46: ...c reset being produced within the CDI Chip 4 11 The HOLD connection to the CDI Chip is at IC2 13 the logic requirements at this point are Hold IC2 13 Free Run O Reset Transition to O The Hold and manu...

Page 47: ...ifier 4 18 The B input is fed in via pin 12 on the main p c b and emitter follower Q1 1 to the input of IC22d which is a dual line receiver adapted by feedback to operate as a Schmitt trigger shaper 4...

Page 48: ...ier is inhibited and the 1 MHz reference is fed to the counter in the CDI Chip The 1 MHz reference from IC2 6 is fed to IC15c which is enabled by a T on IC15c 9 when switch 1S5 is set to CHECK The pul...

Page 49: ...r a summary and diagram of the data output format Multiplex Readout and Display 4 30 The Display Assembly contains a 6 digit readout system using light emitting diode LED numerical indicators The disp...

Page 50: ...on IC9a IC9b and transistors Q29 Q30 and Q31 It produces a display time of approximately 400 ms which is extended to approximately 2 seconds in Time Interval Time Interval Average and Totalize At the...

Page 51: ...us para Segment Check 4 42 This is obtained by selecting CHECK and holding down the manual reset button In Check position the switch 1S5 via R95 applies a 1 to enable IC15a Depressing the manual reset...

Page 52: ...thence via the anti surge fuse FS50 to the transformer T50 The transformer tappings are arranged to suit the local supply voltage as shown in the diagram on page 5 3 The output at secondary winding A...

Page 53: ...egative supply from the rectifiers D11 D14 It also switches off the 5V supply by disconnecting the reference zener diode DIO in the off position CPI Chip 2V Supply 4 52 A stabilized 2V supply is deriv...

Page 54: ...on Millivoltmeter Racal 9301 Coaxial leads 50Q Terminating Pad BNC 50Q quantity 1 Terminating connector BNC 50n T Piece quantity 3 Power Supply 240V 2 50 Hz Single phase line neutral and earth Pulse G...

Page 55: ...rds 5 To replace the covers reverse the above procedure TRANSFORMER VOLTAGE SELECTION 5 2 The instrument will normally be dispatched with the transformer primary tapping set to the 223 251 V supply ra...

Page 56: ...235 265V 94 106V 106 119V 118 132V 0 100 112 125 0 100 112 125 O O p O O I I I I I J LINK L LINK a J 0 lOp 112 125 100 112 125 2 000 00 LINK b LINK d J 0 100 112 125 vO 100 112 125 0 Q 000 j 0 LINK b...

Page 57: ...described in the preceding paragraphs Check that the a c supply voltage is correct 2 With power supply connected switch POWER to ON 3 Using the multimeter Page 5 1 Table 6 item 1 check the d c voltage...

Page 58: ...nd check the display and decimal points Freq column for each n range button 5 Depress the PERIOD A button and verify the readout and decimal points according to the Period column of Table 7 6 Briefly...

Page 59: ...Range button n 10 2 Terminate the A input socket in 50Q and apply 55 MHz at a level of 10 mV r m s 3 Verify a correct and stable count If necessary adjust potentiometer Rll on the main p c b to obtain...

Page 60: ...pulse generator 5 10 Procedure 1 Set the following controls a HOLD NORMAL to NORMAL b Pulse Contact to Pulse c B B B A switch to B B d Depress the Tl button 2 Set the pulse generator to 1 kHz p r f 1...

Page 61: ...Interval Double Line Check 5 11 Equipment Required Pulse Generator Page 5 1 Table 6 item 10 Two BNC T Pieces one 50Q termination 5 12 Procedure 1 Set the B B B A switch to B A and the AC DC switch to...

Page 62: ...se generator bearing in mind the calibration accuracy of the pulse generator Ratio Check 5 14 Equipment Required Pulse Generator Page 5 1 Table 6 item 10 Two BNC T Pieces and one 50Q termination 5 15...

Page 63: ...b HOLD NORMAL to HOLD c AC DC switch to AC d SENSITIVITY control fully anticlockwise 10 mV 6 Set the signal generator to 10 MHz at 10 mV r m s and connect to the terminated A input socket 7 Depress th...

Page 64: ...le warm up period not less than one hour for a temperature controlled oscillator 2 Set the oscilloscope time base to 1 ps cm 3 Connect the 1 MHz external standard to the External Trigger input of the...

Page 65: ...lide back the short length of coloured metal strip into the space normally occupied by the handle boss This will allow access to the screws which secure the front panel to the main frame Remove these...

Page 66: ...r on the rear panel NOTE If preferred the transistor and rectifier can remain connected to the p c b and be unscrewed from their mountings but these items are not supplied with a replacement p c b 5 C...

Page 67: ...b 3 Remove the black plate if fitted from the rear panel trimming aperture and retain the screws 4 Attach the optional frequency standard unit to the inner face of the rear panel align the fixing hol...

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Page 70: ...umerical display LED 7 segment D 1 2 to D I 26 5004 Indicators LED Overflow Gate LP l LP 2 Miscellaneous 25 6027 Flexible wiring 33 way SEVEN SEGMENT DIGITAL INDICATORS The 7 segment indicators normal...

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Page 72: ...0 R1 20 2102 Carbon Film 1 4 5 Ik R2 20 2103 Carbon Film 1 4 5 10k R4 20 2153 Carbon Film 1 4 5 15k R3 Capacitors _v F 21 1616 Cerami c 12 80 20 lOOn Cl 21 2621 Silver Mica 125 5 27p C5 21 2631 Silver...

Page 73: ...Switch push button RESET S52 23 3005 Sockets BNC Inputs A and B For other switches refer to Display Assembly and Main PCB Assembly parts list REAR PANEL ASSEMBLY COMPONENTS 11 1089 17 4057 Transformer...

Page 74: ...4 Cerami c 500 10 220p C9 20 2182 Carbon Film 3 5 1 8k R107 21 1525 Cerami c 500 10 270p Cl 20 2220 Carbon Film i 5 22 R1 19 120 21 1532 Cerami c 500 20 In C27 32 45 20 2221 Carbon Film 1 3 5 220 R21...

Page 75: ...741 23 N Component Reference Part No Tol Description Rat Value Component Reference Transistors IC3 15 22 6101 FET N Channel W300A Q1 22 6009 Silicon npn 2N4124 Q3 27 IC7 22 6079 Silicon npn ZTX313L Q2...

Page 76: ...21 WOH 6021 9901119 0707 1 2 3 4 Fig 3 Component Layout Main RC B Assembly 19 0707...

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Page 79: ...I MHZ STANDABB q p REAfi WnEL 5v I00 WHT areN...

Page 80: ...RMALLY FITTED 2 LINKS LK AND LK2 IN DISPLAY ASSEMBLY a LKl FITTED WITH INDICATORS 26 1505 LATER MODELS b LK2 FITTED WITH INDICATORS 26 1504 EARLIER MODELS 3 R7 IS FITTED IF REQUIRED BY TEST R71 1 1 C3...

Page 81: ...CONNECTIONS WITH SOLID PIN MARKING THUS REFER TO THE FLEXIBLE CONNECTOR BETWEEN MAIN PCB AND FRONT PANEL ASSEMBLY eAToe DISPLAY time NO N AL 1 1 1 i PROMT 1 1 1 PANEL i LiURESET V 1 I 1 SEE i 1 1 WV4T...

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Page 83: ...S5S S 5S SS S3 SS 3S 3S SS Mi SM MMJJit9MtMSM...

Page 84: ...ING EQUIPMENT WHICH PROVIDES HOLD SIGNALS 3 Frequency Meters Normal Use 4 Universal Counter Timers UCT s Basic Hold Requirements 5 UCT s Using Print Hold Mode 5 UCT s Using Holcj Reset Mode 5 SPECIAL...

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Page 86: ...users equipment to the interface for control purposes 2 Print Command a signal output by the interface to indicate that new measurement information is available 3 Print Hold input An input which allo...

Page 87: ...ing counters 9911 and 9919 all timings are doubled except the print command pulse width NEW MEASUREMENT GATE TIME end of gate Fig AI CONNECTION 6 Before connecting the Interface Unit to the counter re...

Page 88: ...a period longer than the gate time check the following pin conditions on the 50 way connector Pin No Required Connection 19 Must be either open circuit 24 or connected to OV 49 Latched Operation 9 Th...

Page 89: ...anged whilst a Hold is applied the counter continues its normal measurement sequence i e free run This has the advantage that the next Print Command will be given at the end of the gate time immediate...

Page 90: ...50 way connector are as follows Pin No Required Connection Pin 19 Connected to Pin 50 or to 5V via 180C Pin 49 Connected to the Hold signal source Pin 24 To be open circuit or connected to O UCT s Usi...

Page 91: ...information becomes available from the previous one Therefore even if the feedback correction is made almost instantly the reading at the end of the next gate time will be incorrect Alternatively if t...

Page 92: ...nding to the end of gate time produced by the reset For cases where the correction time is short less than the Print Command pulse width this may be implemented by linking the Print Command output pin...

Page 93: ...Connected M 12 N Not Connected 13 HOLD RESET P Not Connected 14 See NOTE 1 R Not Connected NOTE 1 In option 01 units with serial numbers after 1389 pin 14 of the flying lead connection is connected w...

Page 94: ...O DIGIT 35 2 i 10 DIGIT 11 4 36 4 12 8 37 8 13 1 38 N 1 14 2 10 DIGIT 39 2 10 DIGIT 15 4 40 4 16 8 41 8 17 OVERFLOW 42 4 10 DIGIT 18 1 10 DIGIT 43 See table 1 NOTE 1 19 HOLD CONTROL I P 44 8 10 DIGIT...

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