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Eddystone 990R, Manual

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Summary of Contents for 990R

Page 1: ...IBDYSTONE RADIO LTD ALVECHURCH ROAD BIRMINGHAM 31 ...

Page 2: ... from the final stage in the IF Channel bandwidth being determined by the setting of the panel selectivity switch Video out put is available on both AM and Fid Audio facilities include outputs for external speaker telephones and remote lines the latter being restricted to permit direct connection to Post Office circuits A separate level control is used for the line amplifier which is totally indep...

Page 3: ...uit Diagram of IP Converter Type 959 9 a 9 9 49 Plan View of 990R Receiver 9 9 9 9 9 9 50 Underside View of 990R Receiver 9 9 9 9 9 51 Internal Layout s Crystal Oscillator Unit 9 A 9 9 9 9 9 52 Internal Layout s s IP Pre Amp Pilter Unit 9 9 9 a 9 52 Block Diagram of 990R Receiver 9 9 O 9 Rear cover Circuit Diagram of 990R Receiver o o A 9 9 Rear cover amenment record Amend No Incorporated by i Dat...

Page 4: ...as IF Amplifier TR17 cm Fairchild IP Amplifier TR18 GM290 Texas Emitter Follower 1 IP OUTPUT TR18A GM290 Texas Emitter Follower 2 FM ISOLATOR TR19 GM290 Texas FM Limiter Driver TR20 GM290 Texas FM Limiter TR21 ASY29 Mullard RF AGC Amplifier TR22 ASY29 Mullard IF AGC Amplifier TR23 GM378 Texas Beat Frequency Oscillator TR24 GM378 Texas CW Detector TR25 GH378 Texas j TR26 GET880 Mullard 1st Noise Am...

Page 5: ...down Up to 75 kHz Calibration Accuracy Within 1fo Crystal controlled markers are available at 10 MHz intervals Prequency Stability S o 1 part in lCr per C change in ambienjfc temperature Of the order 1 part in 10 per C with crystal control IF Bandwidth 30 kHz crystal filter and 200 kHz AGO Characteristic The audio output level does not change hy more than lOdB for an increase in input of 80dB abov...

Page 6: ...I L4 D1 MYJU silicon diode is wired directly across the input to provide some measure of protection for TRl when using the receiver in close proximity to a high power trans mitter The emitter of TRl is fed via SID and CIO from separate low impedance windings on the input tuned circuits All unselected main windings are shorted to ground by SIC which also connects the aerial section of the 4 gang tu...

Page 7: ...d to permit accurate alignment of the oscillator circuit to suit the crystal in use The tuned circuits are adjusted when installing the crystals and allow slight pulling of the crystal to bring the appropriate signal channel into the centre of the i f passband All circuits are identical and have values to suit crystals in the basic range 37 88 MHz Actual crystal frequencies are calculated from fs ...

Page 8: ...the RF Amplifier manual auto gain control line via FC5 Signal output is taken via C77 and C83 to feed both the input switches in parallel from a tap on T2 TR11 GM290 and TR12 GM378 switch the input and output respectively of the crystal filter used in the NARROW selectivity position Overall bandwidth is 30 kHz at 6dB down C78 and C 79 allow accurate matching to the input and output of the crystal ...

Page 9: ...output is available continuously regardless of the MODE SWITCH setting CW Detector Unit TR23 TR25 IP signal is taken from the collector of the final IP Amplifier TRI7 to feed the CW Detector via R76 C159 The Detector proper comprises TR24 and TR25 2 x GM378 signal at IP being applied to the base of TR25 and BPO voltage to the base of TR24 The Beat Oscillator TH23 GM378 is crystal controlled at 10 ...

Page 10: ...fiers TR21 and TR22 2 x ASY29 The diodes which are fed from the final IP Amp lifier TR17 via C144 and C145 drive the bases of the DC Amplifiers more positive on receipt of a signal thus causing their collector currents to increase n p n transis tors Initial no signal collector currents are set by RV5 and RV6 to produce identical control voltages on the AGC line to those obtained with the manual co...

Page 11: ... output and also opening the circuit across the MUTE INDICATOR terminals at the rear of the set THE_AUDIO_SECTION General Audio from TR30 on the Video Board is routed to two separate gain controls RV8 AUDIO GAIN and RV9 1 LINE LEVEL which feed the two independent audio channels Both amplifiers are usable simultaneously in any mode of operation and provide separate out puts for local and remote use...

Page 12: ...e and the AC transformer Connection of the external 12V supply is then by PL9 the 10V line being regulated in the normal manner by the 0AZ228 Fusing and Protection FS1 fuses the negative 12V supply line and is wired to be in circuit for both DC and AC operation On AC an additional fuse FS2 is included in the live line to the power transformer primary Switching is by S10A and SlOB which interrupt b...

Page 13: ...d corner The various printed boards employed are as follows s 1 RP TUNER UNIT TRI TR4 One main board plus four small boards carrying the coils and trimmers for the various stages 2 CRYSTAL OSCILLATOR UNIT TR5 TR7 One main board plus one small board carrying the coils and trimmers in the Crystal Oscillator Stage The crystal holders are mounted on the main board and are accessible after removing the...

Page 14: ...on of the telephone output is taken to ter minals and sockets at the rear of the set The telephone output is brought out on the front panel and accepts a standard Post Office jack plug INSTALLATION GENMAL Accessories All receivers are supplied complete with five standard BNC coaxial connectors a 12V DC supply connector ready wired with shorting strap as per PL8 on circuit diagram and a mains conne...

Page 15: ...version only 5 Pair of tie bars for bench mounted installation 6 Associated cabling and connectors Assembly of EPR30 Panoramic Display Installation 1 Invert receiver and remove the four rubber feet if fitted Attach loudspeaker unit to underside of receiver vising the four screws provided Do not use the screws which previously held the rubber feet 2 Connect the loudspeaker lead to the 30 terminals ...

Page 16: ...ector and three core mains lead are supplied with the set The lead is colour coded as follows RED 1 LIVE BLACK 1 NEUTRAL GREEN s EARTH One end of the lead is left free so that the user can fit a plug of a type sui table for connection to the local supply When operating from AC mains it is important to check that a shorting plug is in position at the 12V DC supply socket Its purpose is to complete ...

Page 17: ...ic display unit from this output in certain applications Adequate drive is available for this purpose IF Output 2 BNC termination Provides output at 10 7 MHz for use with panoramic display or other ancillary units Output is of the order 50mV and bandwidth is determined by the setting of the panel SELECTIVITY SWITCH either 50 or 200 kHz Video Output BNC termination Suitable for external loads of th...

Page 18: ...ed condition The circuit will open l on receipt of a signal 2 if the muting is switched to off or 3 if the receiver supply is removed A lamp with external supply can therefore be installed to indicate to a distant monitoring position that the remote receiver is operational but muted The lamp will extinguish on receipt of a signal If additional signalling facilities are required it is a simple matt...

Page 19: ...Clockwise rotation of the RANGE SWITCH selects a higher frequency range System Switch Selection of the desired mode of local oscillator control is handled by the SYSTEM SWITCH Three modes of operation are possible vizi 1 Manual tuning using the tunable receiver oscillator normal mode marked N 2 Fixed freq working using the crystal controlled receiver oscillator posns 1 8 3 Operation with external ...

Page 20: ...ual or automatic control of gain in the RP and IP Stages of the receiver The manual RP and IP controls are totally inoperative when the switch is set to AGC AGC will be found of greatest value during general search tuning or when monitoring a channel occupied by stations spread over a wide area when considerable variation in strength is likely In most other circumstances and especially when receiv...

Page 21: ...the FM mode the meter needle rests at centre scale and serves only as a tuning indicator deflection from centre being a measure of the degree of off tuning Correct tuning on FM signals is obtained when the needle lies on the red line at the centre of the scale Off tuning in either direction will cause the needle to swing away from centre returning to centre when the signal lies outside the IF pass...

Page 22: ...cations set up In this type of operation the considerable reduction in operator fatigue which results from elimination of inter station noise is a worthwhile feature of which advantage should be taken whenever possible The muting system is brought into operation by putting the panel MUTING SWITCH to the ON position and is set to suit prevailing conditions by adjustment of the pre set MUTING GAIN C...

Page 23: ...nge with satisfactory un rauting on signals of 5RP upwards Care should be exercised to tune slowly making full use of the WIDE selectivity pos ition as a further aid to ease of station selection Variation in noise level from range to range is such that different settings of the MUTING GAIN CONTROL will be required on adjacent ranges This should present little problem since it is doubtful whether t...

Page 24: ... should be by means of the core L17 L24 with the appropriate trimmer set to maximum capacity On the higher frequencies set the core well out and tune with the trimmer C47 C54 Slight jockeying between trimmer and core is quite permissible and inter mediate settings of the trimmer should be used at middle frequencies in the range NB TRIMlERS ARE AT MAXIMUM CAPACITY WHEN THE VISIBLE SILVERED PORTION ...

Page 25: ...all refer ences to the 770R Mk Il VHP Receiver and read instead the notes on the EPR25 Install ation since these are applicable also to the EPR30 990R EPI7R except that the calibrator has a fundamental of 10 MHz It should be noted that in reading page 12 of the EP17R Manual the lowest display frequency when using the 990R Receiver with an EPI7R occurs at the left hand end of the trace This is due ...

Page 26: ...ning the interior Pull instructions for carrying out re alignment will be found later in this Section Lubrication The gear drive and other mechanical arrangements will not normally require attention since these are treated with a permanent lubricant during initial assembly If further lubrication is thought necessary after the receiver has been in use for a prolonged period this can be carried out ...

Page 27: ...to the right hand drive pulley by sliding into slot so that the eyelet is trapped against the inner wall 9 Lift the lower run of cord so that it lies over the two inner guide pulleys whioh prevent it fouling the controls below 10 Check drive for free running by rotating TUNING CONTROL to full extreme of anti clockwise rotation 11 Leave control at this setting slide cursor to 0 on logging scale and...

Page 28: ...Hz to generator set receiver MODE ST ITCH to AM and adjust the attenuator for a reading of approximately 50mW on the output meter Peak the single cores in T6 T7 and T8 for maximum output tuning in each case to the upper peak Repeat these adjustments and then set the attenuator for a precise reading of 50mW output external speaker disconnected Sensitivity should be of the order 180pV If sensitivity...

Page 29: ...or within the passband being achieved as before by comparison with the crystal controlled beat oscillator on 10 7 MHz It is quite immaterial in which order the two filters are aligned Wide IF Filter Signal input at 10 7 MHz is applied via the IF IUPUT socket the output meter being connected to the 30 output as before Access for trimming adjustment is by removal of the small cover at the rear end o...

Page 30: ...ut should be kept at a fairly low level to prevent distortion of the c r t display Scanning should preferably not exceed some 10 sweeps per second with a sweep width of the order 40 50 kHz Reduced sweep width should be used when the receiver is fitted with a narrower non standard filter Overall IP sensitivity should be checked on completion of filter alignment signal applied to IP INPUT socket rec...

Page 31: ...ithin this limit i e 2 4 MHz at 240 MHz 300 kHz at 30 MHz If re alignment of any range should be found necessary proceed as detailed below Remove the top cover from the RF Tuner Unit by taking out the four screws near the corners The cover can be removed with the Calibrator Unit in situ provided that its supply lead and output coax are disengaged at their respective sockets All trimming adjustment...

Page 32: ...d to 75fi and is connected directly to the aerial input socket using a 750 BNC connector The output meter should be fed from the 30 terminals as before Alignment frequencies and adjustments are listed in the Tables which follow trimming following normal procedures with no requirement for special techniques Adjustments should be repeated as necessary Control settings used in previous phases of alig...

Page 33: ...ithin the stab ilisation range of the zener diode D6 which provides the RP AGC delay 9 Check AGC characteristic at 190 MHz on Range 1 and ensure that performance is equal to or better than lOdB change in output for 80 B change in input taken from refer ence level of lOjjiV If performance is not to specification adjustment of the RP AGC AMPLIFIER GAIN RY2 will be necessary though in most cases alte...

Page 34: ...trols set as follows s RANGE SWITCH TUNING SYSTEM SWITCH RF IF GAINS AF GAIN LINE LEVEL MODE SWITCH METER ZERO MANUAL AGC SWITCH IF INPUT SWITCH CALIBRATOR SWITCH Range 1 220 MHz N Normal manual tuning Maximum Maximum Maximum AM Set to zero meter MANUAL OFF up position OR Ref Emitter Base Collector Botes TRl 7 4V 6 8V t 1 2 2V TR2 9 55V 9 IV 0 03V TR3 8 7V 8 3V ov NOTE 1 TR4 C 5Y 6 TV 0 5Y NOTE 2 ...

Page 35: ...TE 3 NOTE 4 NOTE 5 NOTE 6 NOTE 7 NOTE 8 NOTE 9 NOTE 10 SYSTEM SWITCH to N NORMAL SYSTEM SWITCH to EXT No drive applied SYSTEM SWITCH to CRYSTAL Crystal fitted and tuned CALIBRATOR SWITCH to ON SELECTIVITY SWITCH to NARROW SELECTIVITY SWITCH to WIDE Accessible after removal of screening cans Base voltage on both TR18 and TR18A can be measured on underside of printed board without need for taking of...

Page 36: ...pF Air spaced Variable A C6 l 6pF Ceramic Tube Trimmer A C7 O OOlpF Disc Ceramic 20c i 500V A C8 0 047pF Polyester 2QP o 2 50V A C9 O OOImF Disc Ceramic 2Q o 500V A CIO O OOluF Disc Ceramic 2Cf o 500V A Cll O OOImF Disc Ceramic 20 O 500V A C12 O OOlpF Disc Ceramic leadless 5QP b 20 500V A ci3 5 32pF Air spaced Variable A C14 1 6pF Ceramic Tube Trimmer A C15 2 5 6pF Ceramic Trimmer A C16 2 5 6pF Ce...

Page 37: ...Ceramic Trimmer B C53 10 60pF Ceramic Trimmer B C 54 10 60pF Ceramic Trimmer B C55 O OOIjjF Disc Ceramic 20 500V B C 56 O OOluF Disc Ceramic 20 500V B C 57 O OOIjjF Disc Ceramic 20 500V B C58 i O OOIjjF Disc Ceramic 20 500V B C 59 O OOIjjF Disc Ceramic 20 500V B C60 O OOIjjF Disc Ceramic 20 500V B C6l O OOIjjF Disc Ceramic 204 500V B C62 O OOIjjF Disc Ceramic 20 500V B C63 O OOIjjF j Disc Ceramic ...

Page 38: ...02 0 047l Plate Ceramic 80 20 30V E C103 180pF Silvered Mica 5 350V E C104 O OOlpF Disc Ceramic 20 500V E C105 O OOlpF Disc Ceramic 20 500V E C106 0 047PF Plate Ceramic 80 20 30V E C107 0 047PF Plate Ceramic 80 20 30V E C108 0 047MF Plate Ceramic 8070 20 30V i E C109 0 047P 1 Plate Ceramic 80 20 30V E C110 180pF Silvered Mica 5 350V E cm 0 047PF Plate Ceramic 80 20 30V E C112 22pF Tubular Ceramic ...

Page 39: ...E C152 ljjF Tubular Electrolytic 100 20 15V E C153 0 047m Plate Ceramic 80 20 30Y E 0154 0 047m Plate Ceramic 80 20 30V G 0155 30pF Tubular Ceramic 10 750V Gr C156 30pF Tubular Ceramic 10 750V G C157 lOOpF Tubular Ceramic 10 750V G C158 IOjoF Tubular Electrolytic 50 10 16V G Cl 59 O OOImF Disc Ceramic 20 500V G c lb 5d frQlfl HP t SOY 20 30 V M C160 0 01m Metallised Paper 20 200V G C161 10m Tubula...

Page 40: ...6V H C188 100 iF Tubular Electrolytic 100 20 15V H C189 0 5uF Tubular Electrolytic 5 2 J o 50V I C190 100pF Tubular Electrolytic 100 20 15V I C191 0 5 4F Tubular Electrolytic 50 2 50V I C192 500 jF Tubular Electrolytic 100 20 12V I C193 200pF Tubular Electrolytic 10 20 6V I C194 O OOlpF Tubular Ceramic 10 750V I C195 O OlpF Metallised Paper 20 o 200V I C196 200 pF Tubular Electrolytic 100 2 6V I C...

Page 41: ...t g watt 5 watt B R48 15 0000 57 B R49 2 7000 57 D Ref Value Tol Rating Loc R50 1 0000 574 g watt D R51 2 7000 j u g watt B R52 15 0000 57 g watt B R53 4700 57 T watt g watt g watt D R54 15 0000 5 B R55 4 7000 57 B R56 1 0000 57 g watt B R57 1000 57 ft watt g watt 3 watt E R58 1000 57 E R59 1800 57 E R60 2700 57 g watt tjf watt E R61 1 0000 57 E R62 1000 57 watt E R63 1 5000 57 If watt E R64 6800 ...

Page 42: ...36 68 0000 JP g watt E R137 47 0000 Jfo g watt E R138 1000 Jfo g watt E R139 220 Jfo g watt E R140 33 0000 JP watt E R141 3 3000 Jp g watt J R142 2 7000 Jfo jp watt J R143 10 0000 Jp g watt J R144 2 2000 Jp g watt J R145 6800 Jp g watt J RI46 3300 Jp g watt J R147 390 Jfo 1 g watt J R148 1000 Jo ip watt J R149 1 5000 Jfo j g watt J Ref Value Tol Rating Loc R150 4 7000 Jp g watt K R151 4 7000 JP g ...

Page 43: ...h concentric spindles Filtercons Ref Value Wlcgo Vo Type Loc FCl 0 0015 iF 200V Erie Style 1201 052 B FC2 0 0015 xF 200V Erie Style 1201 052 B FC5 0 0015 jF 200V Erie Style 1201 052 B FC4 0 0015 iF 200V Erie Style 1201 052 B FC5 0 0015 200V Erie Style 1201 052 D FC6 0 0015m 1 200V Erie Style 1201 052 D FC7 0 0015m 1 200V Erie Style 1201 052 J FC8 0 0015m 1 200V Erie Style 1201 052 D FC9 0 0015m 1 ...

Page 44: ...743 L6 Range 2 Bandpass coil Primary D3744 L7 Range 3 Bandpass coil Primary D3745 L8 Range 4 Bandpass coil Primary D3746 L9 Range 1 Bandpass coil Secondary D3747 L10 Range 2 Bandpass coil Secondary D3748 Lll Range 3 Bandpass coil Secondary D3749 L12 Range 4 Bandpass coil Secondary D3750 L13 Range 1 Oscillator coil D3751 L14 Range 2 Oscillator coil D3752 L15 Range 3 Oscillator coil D3753 LI 6 Range...

Page 45: ...P CHOKES RF Amplifier Emitter Choke Filter Choke lOV feed to RF Amplifier Low pass Falter Choke Mxer Ip 0utput Filter Low pass Filter Choke Filter Choke lOV feed to Crystal Oscillator Anti parasitic Choke Crystal Isolator Tone Oscillator Choke Gain Control Filter Choke Main IF Gain Control Filter Choke Main IF Filter Chokes 10V feeds on Main IF Board Discriminator Output Filter Choke RF AGC Choke ...

Page 46: ...m Switchs Clicker Mechanism lO position 701 P Wafers ss S3A S3B 6302 IP S3C S3D 7014P S4 Calibrator Switch SPST Toggle Type 4771PB S5 Selectivity Switch DPDT Toggle Type 4772PC S6 Manual AGC Switch DPDT Toggle Type 4772PC si Mode Switch Complete Assy including DPST Supply Switch 7234P 36 Muting Switch SPST Toggle Type 4771PB S9 Monitor Speaker Switch SPST Toggle Type 4771PB S10 See S7 above RVl 3 ...

Page 47: ...axial socket 7292P SK5 Miniature coaxial socket 7292P SK6 Miniature coaxial socket 7292P SK7 Miniature coaxial socket 7292P SK8 BNC coaxial socket 7225P SK9 Two pole chassis mounted one male one female contact 7245P SK10 BNC coaxial socket 7225P SK11 BNC coaxial socket 7225P SKI2 BNC coaxial socket 7225P SKI 3 12V DC Input socket 3 way shrouded male 7130P SKI4 AC Mains input socket 3 way male pola...

Page 48: ...or speaker grille Range indicator lamps 6V 50mA LES LES holder Fuse 1A x If x i cartridge Fuse A x 1 x cartridge Fuseholder Terminals as used for 600Q o p etc Perspex window Cover fixing screws Emitter Follower Unit j ReU j CPPco zV 20 w i 6553P 7006P 7230P 6990P 6101P 6976P 6659P 66OOP 6124P 6244P 6103P 6102P 6977P 5446P LP2946 1 721TP 47 ...

Page 49: ...t the switch S10A and the fuse PS1 in the main receiver This would occur if the ve line was taken via the 12V DC connector A circuit diagram of the converter is given on the following page Other converters can be produced to special order for applications where IP drive is required at other specified frequencies Component Values for IP Converter Type 959 Ref Value Type Tolerance Rating Cl lOuF Tub...

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