TM 11-6625-3017-14 TECHNICAL MANUAL OPERATOR’S ORGANIZATIONAL DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL FOR FM/AM MODULATION METER ME-505 / U (NSN 6625-00-480-8706) HEADQUARTERS, DEPARTMENT OF THE ARMY SEPTEMBER 1981
TM 11-6625-3017-14
TM 11-6625-3017-14 Technical Manual HEADQUARTERS DEPARTMENT OF THE ARMY Washington, DC, 17 September 1981 NO. 11-6625-3017-14 OPERATORS, ORGANIZATIONAL, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL FOR MODULATION METER ME-505/U (NSN 6625-00-480-8706) REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS You can help improve this manual. If you find any mistakes or if. you know of a way to improve the procedure, please let us know.
TM 11-6625-3017-14 CONTENTS (Continued) Paragraph Measuring f.m. deviation Measuring a.m. depth Measuring f.m. on a.m. Measuring a.m. on f.m. Noise measurements Oscillator arrangements Measurement in 1 to 2 MHz range Asymmetric modulation and carrier shift Use of l.f. output terminals Use of I.f. output socket Crystal selection F.m.
TM 11-6625-3017-14 CONTENTS (Continued) Page SECTION 6 CIRCUIT DIAGRAM Circuit notes 6-1 APPENDICES APPENDIX A B References A-1 Maintenance allocation B-1 LIST OF TABLES Table No. 2-1 2-2 2-3 2-4 2-5 4-1 4-2 4-3 4-4 5-1 5-2 Frequency ranges Spurious deviations with increasing % a.m. Spurious deviation with increasing a.m. frequency Crystal selection Decibel conversion table Test equipment required F.m.
TM 11-6625-3017-14 CONTENTS (Continued) LIST OF ILLUSTRATIONS (Continued) Page Fig. No. FO FO FO FO FO FO 4-5 4-6 4-7 4-8 5-1 5-2 5-3 5-4 5-5 5-6 5-7 5-8 5-9 5-10 5-11 5-12 5-13 5-14 5-15 5-16 5-17 6-1 6-2 6-3 6-4 6-5 6-6 F.m. distortion measurement Summation of dB levels A.m.
TM 11-6625-3017-14 SECTION 0 INTRODUCTION 0-1. SCOPE This manual describes F.M./A.M. Modulation Meter ME-505/U (Marconi Model TF 2300A) (fig. 1-1) and provides operation and maintenance instructions. Throughout this manual, ME-505/U is referred to as Modulation Meter type 2300A. 0-2. INDEXES OF PUBLICATIONS a. DA Pam 310-4. Refer to the latest issue of DA Pam 310-4 to determine whether there are new editions, changes, additional publications or modification work orders pertaining to the equipment. 0-3.
TM 11 6625-3017-14 SECTION 1 GENERAL INFORMATION 1.1 INTRODUCTION The TF 2300A Modulation Meter is primarily for measurement of f.m. deviation but it also measures a.m. depth. With its wide range of deviation frequency, modulation bandwidth and carrier frequency, this instrument is suitable for application to fixed and mobile point-to-point communications, broadcasting, telemetry and multi-channel link equipment in the h. f., v. h. f. and u. h. f. bands. Distortion and channel separation tests on f.m.
TM 11-6625-3017-14 1.2 DATA SUMMARY Characteristics Performance Supplementary information R.F. input Frequency range: 4 MHz to 1000 MHz. Sensitivity: Less than 20 mV between 4 and 250 MHz. Typically less than 10 mV. Less than 50 mV between 250 and 500 MHz. Typically less than 25 mV. Less than 100 mV between 500 and 1000 MHz. Typically less than 50 mV. Maximum input: 3 V r. m. s. (200 mW). Input impedance: Nominally 50 Q.
TM 11-6625-3017-14 Characteristics Performance Deviation range: Six ranges with full scale indications of 1.5, 5, 15, 50, 150 and 500 kHz. Positive or negative deviation indication selected by a switch. Modulation frequency: 30 Hz to 200 kHz on all ranges except the 1. 5 kHz deviation range which is limited to 30 Hz to 3.4 kHz. Accuracy: +3% of f. s. d. for deviations up to 500 kHz and modulating frequencies between 30 Hz and 150 kHz, ±5% of f. s.d. on the 1.5 kHz deviation range. +10% of f. s. d.
TM 11-6625-3017-14 Characteristics Performance Supplementary information L.F. output Frequency range: 30 Hz to 200 kHz with switchable 15 kHz low pass filter on f. m. except on the 1.5 kHz deviation range. 30 Hz to 50 kHz on a. m. Typical response curves are shown in Figs. 1-2, 1-3, and 1-4. De-emphasis: Switchable to 0, 50 or 75 ’Sec. Output level: Nominally 0 dBm into 600 Q when meter reads full-scale, except on the 1.5 kHz deviation range when the output is nominally -10 dBm. On the 1.
TM 11-6625-3017-14 Response curves for meter and 1. f. output with de-emphasis off. Fig. 1-2. Typical demodulated f.m. frequency response with internal 15 kHz filter. Fig. 1-3. Typical demodulated f.m. frequency response with internal 200 kHz filter. Fig. 1-4. Typical demodulated a.m. frequency response.
TM 11-66253017-14 1.3 ACCESSORIES Supplied Extension Board type TM 7926; for use when servicing printed circuit boards. Mains Lead type 23424A158 Optional Rack Mounting Conversion Kit type TM 8340. Protective Cover type TM 7958/3; for protection of the front panel during transit. Oscillator crystals. Marconi type Q01670 series; frequencies as specified in Section 2.15. Shielded Adapter, type TB 39868 (Greenpar type GE 51002) for converting OUTPUT terminals to BNC coaxial socket. R. F.
TM 11-6625-3017-14 SECTION 2 OPERATION 2.1 INSTALLATION The Modulation Meter type TF 2300A is available in two versions: with a case for bench mounting, or with a dust cover for rack mounting. The latter version, designated TF 2300AR, fits a standard 19 inch rack. the clip. A 6 BA screw, otherwise housed in a second hole to one side of the clip in the end plate is inserted through the clip and tightened down for long journeys, including delivery.
TM 11-6625-3017-14 lock-plate secured by two screws above the switch, slide the switch button into its other position (as shown on the panel), reverse and replace the lock-plate to hold the button in its new position. No other adjustment is needed. (5) CRYSTAL switch. Selects crystal required. Switch to OFF when not crystal controlled. (6) RANGE switch. Selects internal local oscillator ranges as shown beside tuning dial, or external oscillator. (7) R. F. IN socket. under test. (8) I. F.
TM 11-6625-3017-14 Fig. 2-2. Front panel controls Fig. 2-3. Rear panel 2-3 (19) Supply plug. Accepts Mains Lead type TM 7052 for a.c. operation. (20) H.T. fuse. 500 mA quick-blow type. (21) Mains fuse. 100 mA (for 230 V a.c.) or 160 mA (for 110 V a.c.) slow-blow type. (22) Mains voltage selector. 230 V position for 190260 V, 110 V position for 90-130 V. Reverse locking plate when changing range. (23) Battery terminals. positive earth. (24) MAINS/BATT switch. Select MAINS for a. c.
TM 11-66253017-14 TABLE 2.1. 2.4 PREPARATION FOR USE Frequency ranges It is helpful in reading these instructions and in using the instrument until completely familiar with its operation, to remember that where a control or switch position is marked SET, the control should be adjusted to make the meter read on the line marked SET. RANGE switch setting 1-2 Before commencing measurements: 3-4 (1) Check the mechanical zero of the meter and adjust, if necessary, by means of the screw.
TM 11-6625-3017-14 switch to SET CAL and check that the meter reads SET. If necessary, adjust the f.m. calibration by inserting a screwdriver in the SET CAL F.M. preset and adjusting until the meter reads SET. CAUTION (4) Do not attempt to SET CAL on the 1.5 kHz f.m. deviation range. Noise in f.m. measurements (5) To accommodate signals with up to 100% amplitude modulation the maximum r. f.
TM 11-6625-3017-14 TABLE 2.2 2.9 NOISE MEASUREMENTS By connecting an external meter to the OUTPUT terminals, noise measurements limited only by the noise level generated within the instrument can be made. The internal meter, being peak reading, is not suitable for measuring noise and, ideally, an r.m.s. responding meter should be used. However, sufficiently accurate results are usually obtained with an average reading meter by applying the appropriate correction factor.
TM 11-6625-3017-14 For noise measurements in other bandwidths select the MAX MOD FREQUENCY 200 kHz band- width setting and use a similar type of low-pass filter designed for the required cut-off frequency. (2) The output of the modulation meter is 0. 775 V into 600 n for full-scale deflection on the internal meter. (3) For measurements in the r. f. range 22 MHz to 1000 MHz the local oscillator must be crystal controlled if lowest possible internally generated noise is required.
TM 11-6625-3017-14 actual reading will depend on frequency tolerances in the source and local oscillator output. Switch to DEV +. (7) Remove the modulation from the signal under test. Turn the A.M./DEV RANGE switch to its most sensitive range and then increase the sensitivity of the external meter to give a convenient reading. Record the new level, which is given by the reading on the external meter plus 10 dB for each step of the A. M./ DEV RANGE switch.
TM 11-6625-3017-14 The oscillator takes about two minutes to stabilize after turning on, but this is only of any significance at very high frequencies. 2.10.4 Use above 1000 MHz It is possible to use the instrument above 1000 MHz using internal or external oscillator. With either the variable or crystal controlled oscillator, higher harmonics are sufficiently present to cover the range 1000 to 1600 MHz without loss of sensitivity.
TM 11-6625-3017-14 then causes the meter reading to fluctuate, carrier shift is present. The extent of the shift may be measured by connecting a counter to I. F. OUT. In cases of severe carrier shift, the modulation meter must be set up with modulation on. 2.13 2.15 CRYSTAL SELECTION Crystal control of the local oscillator reduces microphony and pick-up from surrounding equipment where these effects cannot be avoided.
TM 11-6625-3017-14 Example : To find the fundamental crystal frequency for an r. f. input of 83.666 MHz: Crystals are fully specified in Data Sheet Q01670F, to which reference should be made for further details if required. Both data sheet and crystals are available from The Marconi Co. Ltd., Chelmsford, Essex. 1) Consulting Table 2. 4, it can be seen that this r. f. falls within range 4 and the harmonic factor is therefore 2. 83.666+ 1.5 Crystal frequency = 2 = 42. 583 MHz 2.16 F.M.
TM 11-662 5-3014-14 The test arrangement for measuring distortion in an f.m. stereo transmitter is shown for measurements on the G. E. -Zenith system is given below :- For practical working purposes, the small amount of distortion introduced by the modulation meter can be neglected. (1) 2.16.2 Channel separation (2) (3) Connect the transmitter output to the modulation meter in accordance with section 2.4 Preparation for Use.
TM 11-662 5-3014-14 Fig. 2-7. Derivation of composite stereo signal showing unbalance and phase shift errors The test arrangement for measuring channel separation is as illustrated in Fig. 2-6, except that the wave analyser is now replaced by an oscilloscope, and the procedure is as follows : (1) Set up the equipment and modulation meter is already described for distortion measurements. Fig. 2-8.(c). With phase shift error Fig 2-8.
TM 11-6625-3017-14 (2) Apply a test signal to the left channel at 15 kHz modulation frequency (for example) with no signal on the right channel. deviation and divide by the modulating frequency to obtain the answer in radians Telemetry deviation (3) Connect the oscilloscope, switched to d. c. coupling, to the OUTPUT terminals of the modulation meter.
TM 11-6625-3017-14 Table 2.5.
TM 11-6625-3017-14 Table 2-5.
TM 11-6625-3017-14 SECTION 3 TECHNICAL DESCRIPTION This limited i. f. waveform is passed to the pulse counter discriminator whose operation is illustrated in (c), (d) and (e). A pulse of fixed amplitude and width is generated every time the clipped i. f. signal passes through zero in the positive-going sense as shown in (b) and (c). At any given repetition frequency, these pulses have a constant mean amplitude, Vm, provided the pulse amplitude and width are fixed; thus when the p. r. f. varies due to f. m.
TM 11-6625-3017-14 the carrier level at the detector, while in the latter position, when the i. f. is fixed, it is used to set the mixer input to the correct level by adjustment of the LEVEL attenuator and also for oscillator peaking adjustment during initial setting up of the modulation meter. A.M./F.M. sections The A. M. /DEV RANGE attenuator has a total attenuation of 40 dB. The attenuation in the 1.
TM 11-6625-3017-14 itors. One switch, SA, on the back panel selects the mains voltage range, and another, SB, the power source which may be mains or battery. where mixing with the local oscillator takes place. The output from the mixer is at an i. f. of 1.5 MHz. The normal input range is 4 MHz to 1000 MHz. R. F. inputs of over 1000 MHz can be used with reduced sensitivity. The useful upper limit is governed by oscillator stability and input sensitivity.
TM 11-6625-3017-14 a d. c. term, Vm, almost proportional to the repetition frequency. This d. c. is fed, in the SET FREQ positions of the Function switch, directly to the meter which is arranged to indicate SET when the i. f. is correct. 3.5 I.F. AMPLIFIER (Unit A3-Fig. 7-2) This board, in the narrow box alongside the local oscillator and power unit, contains three amplifying stages, each of two transistors, Q1 to Q6, the stages being coupled via band pass filters.
TM 11-6625-3017-14 Since the multivibrator runs at constant frequency, the positive-going pulses from Q4 are at equal time intervals. Q7 and Q8 divide these 4 kHz pulses by two and produce an exactly 1:1 square wave output, via C11, at about 2 kHz. Q5 and Q6 operate as a gating circuit controlled at 2 kHz by this square wave. 200 kHz and 15 kHz These filters are 3 dB down at 250 and 28 kHz respectively to obtain optimum flatness over their pass ands of 200 and 15 kHz.
TM 11-6625-3017-14 Q2; one via a switch, so that on the 5 to 500kHz deviation ranges the meter circuit is connected to terminal 7, and the other from terminal 9 to the DEEMPHASIS switch. On the 1.5 kHz deviation range the meter circuit is connected to the output of the amplifier by terminal 11. output impedance of Q3. This gives the circuit a wide band response which is flat to within the limits of the i. f. amplifier.
TM 11-6625-3017-14 SECTION 4 MAINTENANCE units above and below the chassis. Components may be identified by markings on the boards and chassis. For replacement of sub-assemblies and components, see Sects. 5. 5 and 5. 6. 4.1 INTRODUCTION This section contains information for keeping the equipment in good working order and for checking its overall performance. 4.
TM 11-6625-3017-14 Fig. 4-1.
TM 11-6625-3017-14 Fig. 4-2.
TM 11-6625-3017-14 Table 4.1. Test Equipment Required. Item (3) (4) Type Minimum specification a A. M. signal generator Output: 100 mV across 50 Q A. M.: 80% Envelope distortion: 1% at 50% mod. TF 2002B b F. M. signal generator Deviation: 4 to 250 kHz Mod. freq.: 0 to 200 kHz Spurious a. m.: 1% TF 2008 c F. M. signal generator Output: 200 mV across 50 n Deviation: 4 to 250 kHz Mod. freq.: 0 to 200 kHz TF 1066B/6 (Mod. freq.: 40 Hz 100 kHz) d Electronic voltmeter Sensitivity: 10 mV r. m.
TM 11-6625-3017-14 (1) Connect the signal generator, externally modulated by the l. f. oscillator, to the inputs of the modulation meter and the spectrum analyser, as shown in Fig. 4-3. I.F. output and frequency (6) Connect the frequency meter and voltmeter to the I.F. OUT socket and check that the i.f. is approx.200 mV (with the meter reading at the bottom ofthe black arc) and remains within 10% of 1.5 MHz when the modulation depth of the input signal is varied from 0 to 80%o.
TM 11-6625-3017-14 Function switch to SET CAL and, without disturbing the SET CAL F. M. preset, bring the meter reading to the SET mark by adjust-ing the internal f. m. preset, AORV3 - see Fig. 4-1. If this has insufficient range select a new value for resistor AOR15. (5) This check can also be made at other deviations as shown in Table 4.2.
TM 11-6625-3017-14 Fig. 4-4. F.M. noise measurement To ensure that the latter output is due to the modulation meter alone it is important that the source should be exceptionally free from spurious noise deviation. (1) Apply an f.m. input with 5 kHz deviation from the signal generator. Connect the oscilloscope, filter and voltmeter to the OUTPUT terminals as shown in Fig. 4-4. (2) Set the modulation meter for deviation measurement as in Sect. 2.5, with the local oscillator crystal-controlled (see Sect.
TM 11-6625-3017-14 2nd harmonic: (fl -f2): 2 kHz 3rd harmonic: (2f2 -fl): 12 kHz and express them in dB’s relative to 0 dB. Add +6 dB to the 2nd harmonic reading and +9 dB to the 3rd harmonic reading. The r. m. s. sum of the two levels (see below for method of calculation) should be lower than -54 dB (0. 2%. Distortion limits for other values of deviation and modulation frequency are given in Sect. 1.2 - Data Summary. Fig. 4-7. A.M. rejection measurement (3) Switch to F. M.
TM 11-6625-3017-14 Fig. 4-8.
TM 11-6625-3017-14 SECTION 5 REPAIR (iii) Systematic calibration, which can be used to locate a fault for which methods (i) and (ii) are inadequate - see Sect. 5.4. 5.1 INTRODUCTION This chapter contains information for the localization and repair of faults. Performance limits quoted are for guidance only and should not be taken as guaranteed performance specifications unless they are also quoted in the Data Summary section. 5.2.1 Test equipment required See Table 5.1. CAUTION See Maintenance, Sect.
TM 11-6625-3017-14 OSCILLATOR TUNE and LEVEL controls, a meter deflection in the black arc can be obtained. If so, the local oscillator, mixer and i. f. amplifier (Al to A3), most of the a. m. detector (All) and the peak reading voltmeter (A10) are working. (2) If not, but the meter deflects when the input frequency is changed to the i. f. of 1.5 MHz, then the-local oscillator or mixer are suspect.
TM 11-6625-3017-14 Fig. 5-1. Oscillograms The conditions to obtain these waveforms are as follows: DE-EMPHASIS switch to OFF. Function switch to SET CAL.
TM 11-6625-3017-14 TABLE 5.2 Test Equipment Required for Realignment Item Type Minimum specification Recommended model a Multimeter Range: 0 - 20 V d. c. 0 - 270 V a. c. Hewlett-Packard HP410A b Variable mains transformer Range: 190 - 260 or 90 - 160 V a. c.
TM 11-6625-3017-14 -12 V line should be not more than +2 mV, and preferably about +1 mV. 5.4.3 Power supply Test equipment:- a, b, c and d (1) 5.4.4 Measure the output of the -18 V and -12 V regulated supplies at the points illustrated in Fig. 5-2.. Test equipment:- e, f, g' and h (1) Connect the frequency meter and millivolt-meter via a T-connector to the output plug of the oscillator, PLB. Turn the LEVEL control fully clockwise.
TM 11-6625-3017-14 Output Attenuator: Sweep Width control: Centre Frequency control: Y1 Gain control: Y1 switch: Y2 switch: 30 or 40 dB. maximum sweep. frequency; the frequency blip will then be shown on the Polyskop. It is advisable to adjust the Polyskop frequency control and the OSCILLATOR TUNE control together, so that the correct frequency blip remains on the screen. mid-way. maximum gain. B. off. (7) Set the TF 2300 controls as follows: SUPPLY: Oscillator RANGE: CRYSTAL: on. RANGE 5 - 8.
TM 11-6625-3017-14 (2) Connect the voltmeter to the OUTPUT terminals. 5.4.8 (3) Turn the DE-EMPHASIS switch to 75 µ sec, the Function switch to DEV+ and the MAX MOD FREQ to 200 kHz. Test equipment: j and k (4) (5) Set the signal source frequency to 100 Hz and adjust its output level to give a suitable reference deflection on the output voltmeter.
TM 11-6625-3017-14 and Q6 in the discriminator (A5) and/or by selecting a new value for A5R13. 5.4.10 Set l.f. Test equipment: 1 5.5 REPLACEMENT OF SUB-ASSEMBLIES (1) Connect the crystal oscillator to the R. F. IN socket. Oscillator (2) Turn the oscillator RANGE switch to EXT and the Function switch to TUNE. (3) Set the LEVEL control for a meter reading at the ’top end of the black R. F. LEVEL arc. (4) Turn the Function switch to F. M. SE.
TM 11-6625-3017-14 (5) Limiter and discriminator All thirteen connections are soldered; the complete unit can be removed after these have been unsoldered by releasing four nuts from the top side of the chassis. The cover is removable to give access to all the circuits and presets. Starting from point Y, wind the cord 7 1/2 times counter-clockwise round the bush, take it over pulley B, through the slot in pulley C and attach it to the other spring at point Y’.
TM 11-6625-3017-14 Fig. 5-5.
TM 11-6625-3017-14 Fig. 5-6.
TM 11-6625-3017-14 Fig. 5-7.
TM 11-6625-3017-14 Fig. 5-8. Parts location, I.F.
TM 11-6625-3017-14 Fig. 5-9.
TM 11-6625-3017-14 Fig. 5-10.
TM 11-6625-3017-14 Fig. 5-11. Parts location, 1st L.F.
TM 11-6625-3017-14 Fig. 5-12. Parts location, 2nd L.F.
TM 11-6625-3017-14 Fig. 5-13.
TM 11-6625-3017-14 Fig. 5-14. Parts location, A.M.
TM 11-6625-3017-14 Fig. 5-15.
TM 11-6625-3017-14 Fig. 5-16.
TM 11-6625-3017-14 Fig. 5-17.
TM 11-6625-3017-14 APPENDIX A REFERENCES DA Pam 310-4 Index of Technical Manuals. TM 11-6625-537-15 Operator’s, Organizational, Field and Depot Maintenance Manual: Voltmeter, Electronic, ME-202/U TM 11-6625-573-14 Operator’s, Organizational, Direct and General Support Maintenance Manual for Signal Generator,AN/GRM-50 (FSN 6625-868-8353). TM 11-6625-2658-14 Operator’s, Organizational, Direct Support, and General Support Maintenance Manual for Oscilloscope AN/USM-281C (NSN 6625-00-106-9622).
TM 11-6625-3017-14 SECTION 6 CIRCUIT DIAGRAM CIRCUIT NOTES 1 ARRANGEMENT The inter-unit wiring diagram, FO 6-1, shows all sub-assembly units in the equipment together with their reference designators (A1, A2 etc. ) and type numbers (prefixed TM). Components that are not on a subassembly are part of the main chassis assembly (designated AO). Circuit diagrams are arranged in order of the subassembly designations. 2. COMPONENT VALUES Resistors : No suffix = ohms, k = kilohms, M = megohms.
TM 11-6625-3017-14 APPENDIX B MAINTENANCE ALLOCATION Section I. INTRODUCTION system so that their functions are properly synchronized. This does not include setting the frequency control knob of radio receivers or transmitters to the desired frequency. B-1. General This appendix provides a summary of the maintenance operations covered in the equipment literature.
TM 11-6625-3017-14 k. Rebuild. The highest degree of materiel maintenance. It consists of restoring equipment as nearly as possible to new condition in accordance with original manufacturing standards. Rebuild is performed only when required by operational considerations or other paramount factors and then only at the depot maintenance category. Rebuild reduces to zero the hours or miles the equipment, or component thereof, has been in use. Code Maintenance Category C.......................
TM 11-6625-3017-14 SECTION II. MAINTENANCE ALLOCATION CHART FOR MODULATION METER ME-505/U (1) GROUP NUMBER 00 (2) (3) (4) COMPONENT ASSEMBLY MAINTENANCE FUNCTION MAINTENANCE CATEGORY C O F H D Meter, Modulation ME-505/U Inspect 0.5 (Marconi Model TF 2300A) Test Test 0.
TM 11-6625-3017-14 SECTION III.
TM 11 6625-3017-14 SECTION IV. REMARKS REFERENCE CODE REMARKS A Replacement of knobs, fuses and lamps. B Repaired by replacement of boards. C Repair boards.
By Order of the Secretary of the Army: E. C. MEYER General, United States Army Chief of Staff Official ROBERT M. JOYCE Brigadier General, Unites States Army The Adjutant General DISTRIBUTION: To be distributed in accordance with special mailing list.
TM 11-6625-3017-14 FO Fig. 6-1.
TM 11-6625-3017-14 FO Fig. 6-2. Mixer, oscillator and i.f.
TM 11-6625-3017-14 FO Fig. 6-3. Limiter, discriminator and 1st l.f.
TM 11-6625-3017-14 FO Fig. 6-4. 2nd l.f.
TM 11-6625-3017-14 FO Fig. 6-5. A.M.
TM 11-6625-3017-14 2300A (USA) JAN 1974 FO Fig. 6-6.
PIN: 049597-000
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