TM 11-6625-496-45 DEPARTMENT OF THE ARMY TECHNICAL MANUAL FIELD (FOURTH ECHELON) AND DEPOT MAINTENANCE MANUAL TEST SET, RADIO AN/VRM-l This copy is a reprint which includes pen and ink Changes in force at the time of publication.
Changes in force: C#2 C#4, C#5 and C#6 TM 11-6625-496-45 C6 HEADQUARTERS DEPARTMENT OF THE ARMY Washington, DC, 12 March 1980 Change No. 6 General Support and Depot Maintenance Manual Including Repair Parts and Special Tools Lists TEST SETS, RADIO AN/VRM-1 AND AN/VRM-1A (NSN 6625-00-892-5542) TM 11-6625-496-45, 3 July 1962, is changed as follows: The title of the manual is changed to read as shown above. Page 2. paragraph 1, subparagraph c is superseded as follows: c.
tant high current through the base-to-emitter of Q7802 and R7811 (15 ohms) to ground would cause both Q7803 and R7811 to fail. Page 8, paragraph 9a: First sentence, delete *’R7902° and replace it with R7802. Page 9, paragraph 10c: Third sentence, line 8; delete “base” and replace it with collector. Page 9, paragraph 10d: In line two, delete "DS7902 and DS7901" and replace it with DS7901 and DS7902. Page 11, paragraph 12b: In line 4; change “R7817" to R7921 .
Figure 9. Tests in selector switch positions A. 2..3, and 7. simplified schematic diagram.
Page 14, paragraph 19: In last line, change "475” to 402. Paragraph 22: In line 5, add “R7918” after C7901. Paragraph 23, line 5. “R7901” is changed to read R7910. Page 16, paragraph 27.1. The following sentence is added after the second sentence: In some equipment (para 1d(5)(d)), the tested voltage is connected through rf choke L7301 and across voltage divider network consisting of variable resistor R7919 and resistors R7922 and R7920. Figure 10.1 is superseded by new figure 10.1. Figure 10.1.
Page 22, paragraph 34b. Add the following to the chart: Contact No. S7902A and S7902B 2. 19 . 19 Value (ohms) Resistor R7902 and R7923 X7919 R7919 and R7922 8,500.. 5,230 .. 5,300 .Two resistors provided in certain equipment; see paragrah 1d(5)(d). ““Value measured will depend on position of potentiometers R7902 and R7919. Page 23. New figure 11.2 is added after figure 11.1.
Figure 11.2.
Page 27, paragraph 38. Make the following changes: Subparagraph p. The following note is added: NOTE If diode CR7901 is type 1N645 (NSN 596100-577-6084), replace it with type 1N4383 (NSN 5961-00-756-6578) (72699); para 1d(5) (b)). Subparagraph r. The following is added before subparagraph (1): Before inserting diode CR7902 in its mounting hole, apply a thin evenly spread coating of Dow Corning No.
R7902 IS R7923 (1100 OHMS ) WHEN POTENTICMETERS R7902 AND R7919 PROVIDED ON CONTRACT DAAB05 -73 – 6 - 1632 (1973) AND ARE SUCEEDING CONTRACTS. EL4YC004 Figure 15. Test Set, Radio TS-1777/VRM-1 and TS-1777A/VRM-1 front panel chassis, top view. Page 35, paragraph 43. The following is added after subparagraph d: d.1. DC Circuits (Positions 2 and 19).
Page 59 Paragraph 57b(5) 57b(6) 57C(3) 57C(4) Change +4.0 volts + 5.5 volts 10.500 mc + 1.0 volt dc ±0.30 13.000 mc +1.0 volt dc ±0.30 To + 3.5 volts + 5.0 volts 10.75 mc ±40 cps 3.00 volts dc ±0.05 10.10 mc ±40 cps 1.65 volts to 275 volts dc 57C add new paragraph: (5) Adjust the 606A frequency to 11.60 mc ±40 cps while maintaining a 411A indication of 10 mv. A normal indication should be 1.65 to 2.75 volts dc.
By Order of the Secretary of the Army: Official: E. C. MEYER General, United States Army Chief of Staff J. C. PENNINGTON Major General, United States Army The Adjutant General Distribution: To be distributed in accordance with DA Form 12-51, Direct and General Support maintenance requirements for AN/VRM-l.
Changes in force: C 2, C 4, and C 5 TM 11-6625-496~5 *C 5 HEADQUARTERS DEPARTMENT OF THE ARMY W ASHINGTON , D. C., 4 June 1973 C HANCE No. 5 General Support and Depot Maintenance Manual Including Repair Parts and Special Tool List TEST SETS, RADIO AN/VRM-1 AND AN/VRM-1A TM 11-6625-496-45, 3 July 1962, is changed as follows: Page 2, paragraph 1, Delete subparagraph b. Paragraph 1, Delete subparagraph c and substitute the following: c.
APPENDIX II GENERAL SUPPORT AND DEPOT MAINTENANCE REPAIR PARTS AND SPECIAL TOOLS LIST Section I. INTRODUCTION 1. Scope This appendix lists repair parts required for the performance of general support and depot maintenance of the AN/VRM-1 and AN/VRM1A NOTE No special tools, test, or support equipment is required. 2. General This repair parts list is divided into the follow-. ing sections: a. Repair Parts-Section II.
Explanation Code R—Repair parts and assemblies that are economically repairable at DSU and GSU activities and are normally furnished by supply on an exchange basis. T—High-dollar value recoverable repair parts which are subject to special handling and are issued on an exchange basis. Such repair parts normally are repaired or overhauled at depot maintenance activities. b. Federal Stock Number, Column Z .
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT.
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT GFNERAL SUPPORT AND DEPOT MAINTENANCE ( CONTINUED) 6
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE (CONTINUED) 7
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT GENERAL SUPPORT AND DEPOT MAINTENANCE(CONTINUED) 8
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE (CONTINUED) 9
TM 11-6625-496-45 SECTION 11 REPAIR PARTS FOR DIRECT SUPPORT.
TM 11-6635-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED ) 11
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED) 12
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE (CONTINUED) 13
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERA SUPPORT, AND DEPOT MAINTENANCE (CONTlNUED) 14
TM 11-6625-496-45 SECTlON II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT 15 AND DEPOT MAINTENANCE (CONTINUED )
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED) 16
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED ) 17
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED) 18
TM 11-6625-496-45 SEClTON II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED) 19
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED) 20
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT, AND DEPOT MAINTENANCE (CONTINUED) 21
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE (CONTINUED ) 22
TM 11-6625-496-45 SECTION II REPAIR PARTS FOR DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE (CONTINUED) 23
TM 11-6625-496-45 SECTION III INDEX-FEDERAL STOCK NUMBER AND REFERENCE NUMBER CROSS REFERENCE TO FIGURE AND ITEM NUMBER OR REFERENCE DESIGNATION FEDERAL STOCK NUMBER FIGURE NUMBER FIGURE NUMBER 5305-543-2761 52 H7510 H7917 5305-543-5059 55 H7903 . t ITEM NUMBER OR REF. DESIGNATION FEDERAL STOCK NUMBER ITEM NUMBER OR REF.
TM 11-6625-496-45 SECTION III INDEX-FEDERAL STOCK NUMBER AND REFERENCE NUMBER CROSS REFERENCE TO FIGURE AND ITEM NUMBER OR REFERENCE DESIGNATION (CONTINUED ) 25
TM 11-6625-496-45 INDEX-FEDERAL STOCK NUMBER AND REFERENCE NUMBER CROSS REFERENCE TO FIGURE AND ITEM NUMBER OR REFERENCE DESIGNATION ( CONTINUED ) 26
TM 11-6625-496-45 27
TM 11-6625-496-45 28
TM 11-6625-496-45 29
TM 11-6625-496-45 30
TM 11-6625-496-45 31
TM 11-6625-496-45 32
TM 11-6625-496-45 33
TM 11-6625-496-45 31
TM 11-6625-496-45 35
TM 11-6625-496-45 36
SECTION IV TM 11-6625-496-45 INDEX-REFERENCE DESIGNATION CROSS REFERENCE TO PAGE NUMBER (CONTINUED ) REFERENCE DESIGNATION .
M 11-6625-496-45 SECTION IV INDEX- REFERENCE DESIGNATION CROSS REFERENCE TO PAGE NUMBER (CONTINUED ) PAGE NUMBER REFERENCE DESIGNATION REFERENCE DESIGNATION PAGE NUMBER REFERENCE DESIGNATION PAGE NUMBER MP7217 12 MP7914 17 R7405 6 MP7218 12 MP7915 18 R7406 6 MP7219 12 P71OO 5 R7407 6 MP7220 12 P7101 5 R7408 6 MP7221 12 P7401 6 R7409 6 MP7222 12 P7501 13 R7410 6 MP7222 13 P7601 7 R7501 14 MP7223 13 P7701 22 R7601 8 MP7224 13 P7801 19 R7602 8 MP7225
TM 11-6625-496-45 SECTION lNDEX- REFERENCE DESIGNATION IV CROSS REFERENCE TO PAGE NUMBER (CONTINUED ) REFERENCE DESIGNATIUN PAGE NUMBER REFERENCE DESIGNATION PAGE NUMBER R7715 22 R7913 18 R7716 23 R7914 18 R7717 23 R7917 17 R7718 22 R7918 14 R7801 20 R7919 “18 R7802 20 R7920 14 R7803 20 R7921 14 17 R7804 21 S7901 R7805 20 S7902 19 R7806 20 T7601 8 R7807 20 T7602 8 R7808 20 T7702 23 R7809 20 TB7300 16 R7811 20 TB7400 6 R7812 20 TB7500 14 R7813
Figure 40. Test Set, Radio AN/VRM-1, components and running spares.
Figure 41. Branched power cable, partially disassembled.
Figure 42.
Figure 43. 38 Audiofrequency amplifier printed circuit card A7400.
Figure 44. Teat set, case removed, adjustable components, rear view.
Figure 45. 40 11.5-MHz amplifier printed circuit card A7600.
Figure 46. Case, test set removed, gaaket and bumpers (AN/VRM-1).
Figure 47. Test Set, Radio AN/VRM-1A, case cover and instruction plates. Figure 48.
Figure 49. Test Set, Radio AN/VRM-1, cover components.
Figure 50. Cover assembly (AN/VRM-1A). Figure 51. 44 Ted set, case removed, three-quarter view from top.
Figure 52. Band pass filter printed circuit card A7500.
Figure 53. Test probe assembly.
TEST SET SUB-ASSEMBLY (CAPACITOR- RESISTOR ASSEMBLY) SECTION A-A Figure 54. EL6625-496-40P-TM-15 Test set, front panel and chassis, chassis bottom plate removed, rear view.
Figure 55. Test set, front panel and chassis, bottom view.
Figure 56. Test set, front panel and chassis, left view.
Figure 57. Test probe, radiofrequency preamplifier.
Figure 58. Teat set, front panel and chassis, top view.
Figure 59. Lamp driving gates printed circuit card 7800.
Figure 60. Radiofrequency amplifier printed circuit card A 7700.
By Order of the Secretary of the Army: Official: VERNE L. BOWERS Major General, United States The Adjutant General CREIGHTON W. ABRAMS General, United States Army Chief of Staff Army . Distribution: To be distributed in accordance with DA Form 12-51 (qty rqr block No. 599) Direct and General Support Maintenance requirements for AN/VRC-12.
Changes in force: C 2, C 3, and C 4 TM 11-6625-496-45 C 4 HEADQUARTERS DEPARTMENT OF THE ARMY W ASHINGTON , D.C. 9 July 1970 CHANGE No. 4 GS and Depot Maintenance Manual Including Repair Parts and Special Took Lists TEST SETS AN/VRM-1 AND AN/VRM-1A TM 11-6625-496-45, 3 July 1962, is changed as follows: The title of this manual is changed as shown above. NOTE . “GS” maintenance stands for general support maintenance.
NOTE New plates should be requisitioned for those tat sets that do not have plates described in (4) above Paragraph 2 f, line 9. Change “22 volts” to: 21.5 volts. Page 5, figure 2. Make the following changes: Change the resistance value of “R7612” and “R7613” to: 51 (ohms). Add the following: NOTE In some units, the resistance value of R7612 is 75 ohms and R7613 is 33 ohms. Page 11, figure 8. Make the following changes. Change the resistance values of “R7818" to “51 (ohms) “ and “R7819” to “8.
Figure 11.
Add figure 11.1 after figure 11. Figure 11.
Page 24, paragraph 36. Add the following as the introductory paragraph: The front panel and chassis of the TS-1777/VRM1 (AN/VRM-l) and TS-1777A/VRM-l (fig. 11.1) (AN/VRM-lA) are identical in dimensions but the case of each is different (para 1 d). Consequentlyt the front panel and chassis of either odel can be put in the case of the other model Page 33, paragraph 43.
Figure 23.1. TS-1777A/VRM-1 (and later production units of TS-1777/VRM-1), bottom view and location of adjustable controls. Paragraph 44. Add subpagraph c after subparagraph b. c. Refer to the appropriate adjustment procedures given in Paragraph 62 through 69 when the test requirement of a particular circuit (para 47 through 51) cannot be obtained.
changes in the “Performance Standard" column. +19.00 and +21.80. In step 2b, change “+14.2” to: between +13.40 and +15.00. In step 4b, change “+10.50” to: between +9.90 and +1120. In step 2c, change “+17.6” to: between +17.30 and +19.50. In step 4c, change “+13.00” to: between +12.70 and +14.20. Add step No. 5 after step No. 4. In step 3b, change “+20.7” to: between Step No. 5 Test equipment control settings Sane as step No. 4 Equipment under test control settings Same as step No.
Indicattor Signal at probe tip Selector switch S7902 position A 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Type Note 1) Note 2) dc dc dc dc dc af af (Note 3) af af (Note 3) af af (Notc3) af af (Note 3) rf rf dc dc dc rf rf af af (Note 3) af af (Note 3) rf rf rf rf rf rf rf rf rf rf rf rf rf rf dc dc Frequency Voltage RED . . . . . . . l kc l kc l kc l kc l kc l kc l kc l kc 11.5 mc 11.5 mc . . . 11.5 mc 11.5 mc 1 kc 1 kc 1kc 1 kc 5.65 mc 5.65 mc 11.5 mc 11.5 mc 11.5 mc 11.5 mc 5.65 mc 5.65 mc 5.
Page 55, paragraph 54b (3), chart Add the folwing item to the chart: Test equipment Technical manual multmeter, Electronic AN/URM-146 . . . . . TM 11-6625-524-15-1 Pages 59. Add figure 30.1 after figure 30. Figure 30.1.
Subparagraph h(2), line 5. Change “ME 30B/U to: AN/URM-145. Page 63, figure 31. In figure 31, change callout “Q7606-C” to: Q7602-C. Page 65 (page 2 of C 2), paragraph 61a, chart. Delete the chart and substitute: (1) TM 11-6625-496-12, with current changes. (2) TM 11-6625-496-45, with current changes. (3) TB SIG 355-1. (4) TB SIG 355-2. (5) TB SIG 355-3. Page 3 of C 2, paragraph 61b, line 4. Change “DA Pam 310-4” to: DA Pam 310-7. Page 66 (page 3 of C 2), paragraph 63.
By Order of the Secretary of the Army Official: W.C. WESTMORELAND, General, United States Army, Chief of Staff. KENNETH G.
Distribution: To be distributed in accordance with DA Form 12-51 Direct/General Support maintenance literature for AN/VRC-12, AN/VRC-43, AN/VRC-44, AN/VRC-45, AN/VRC-46, AN/VRC-47, AN/VRC-48, AN/VRC-49 radio equipment.
TM 11-6625-496-45 *C 2 Field (Fourth Echoion) and Depot Maintenance Manual TEST SET, RADIO AN/VRM-1 CHANGE No. 2 HEADQUARTERS DEPARTMENT OF THE ARMY WASHINGTON, D.C., 23 April 1964 TM 11-6625-496-45, 3 July 1962, is changed as follows: Page 7, paragraph 8a(2) (as change by C1,13 Page 2, paragraph 1. Delete subparagraph c Jan 64). At the end of subparagraph (2), insert: (including the note) and d and substitute: Note. In some test” probes, L7302 has been rec.
NOTES: 1. IN SOME SETS L7302 HAS BEEN REMOVED AND R7204 AND C7304 HAVE BEEN WIRED IN AS SHOWN. 2. IN SOME SETS C7304, R7304, AND THE .1 Of CAPACITOR ARE CONNECTED AS SHOWN AND MOUNTED INSIDE THE TEST SET CASE. 3. UNLESS OTHERWISE INDICATED, RESISTANCES ARE IN OHMS. TM6625-496-45C1-1 Figure 5.1. Test probe RF preamplifier, showing changes in wiring of components. Page 16, paragraph 26 (as changed by C 1, 13 Jan 64) Make the following changes: Subparagraph a, line 6. Change “’113” to: 66.5.
b. Additional Equipment. Perform all b.- .Modification Work Orders. . . applicable modification work orders (MWO) pertaining to this equipment before making the tests Specified. DA Pam 310-4 lists all available MWO’s. 62. Test Facilities Required The following equipments, or suitable equipment, will be employed in determining compliance with the requirement of this specific standard a. Test Equipment. 63.
Figure 34.1. (Added) Special junction box. f. Connect the dc leads of the ME-26A/U to terminals A (ground) and J (B+) of the 18terminal female connector of the CX-7899/VRM1. The voltage must be between 21 and 22 volts dc. Note. For the remaining tests, l djust the model 3206 power supply form output between +23.4 and +28.6 volts dc. g. Connect the AN/USM-98 positive lead to TS-1777/VRM-l test jack A, and the negative lead to the probe ground connector. The voltage indicated must be between 15.2 and 16.
Figure 34.2. (Added) Special test cable. USM-98 across the probe tip and the probe ground connector. d. Carefully increase the output from the PP 3514/U and note the voltage indicated on the AN/USM-98 when the TS-1777/VRM-1 RED indicator goes out and the GREEN indicator lights. This action must occur when the indicated voltage is between 13.40 and 15.00 volts dc. e.
l. Carefully increase the output from the PP3514/U and note the voltage indicated on the AN/USM-98 when the RED indicator goes out and the GREEN indicator lights. This action must occur between 13.00 and 14.70 volts dc. Decrease the output of the PP-3514/U to 0 volt dc. m. Remove the PP-3514/U, the special junction box, and the AN/USM-98 from the TS-1777/ VRM-1 probe assembly. 66. Audio Voltage Test (fig. 34.5) a.
put of the TS-421/U until the RED indicator lights. e. Turn the selector switch to 6, f. Carefully increase the output from the TS421/U and note the voltage indicated on the ME30A/U when the RED indicator goes out and the GREEN indicator lights. This action must occur between 0.450 and 0.520 volt. Decrease the output of the TS421/U until the RED indicator lights. g. Turn the selector switch to 6. h.
a. Carefully increase the output from the AN/ GRM-50and note voltage indicated on the AN/URM-145 when the RED indicator goes out and the GREEN indicator lights. Check to be sure that the output is still 5.65 mc ±100 cps and that the change in indicator occurs between 0.125 and 0.250 volt. f. Remove temporary connections A and B (fig. 34.6) and make temporary connection C. Adjust the AN/GRM-50 for an output of 5.
Figure 34.
Caution: check to be sure that signal voltages are removed from the brfore setting the TS-1777/VRM-1 ON-OFF switch to OFF. e. Remove all test connections and turn the power off. Page 69. Add to the appendix: Depot Inspection Standard for TB SIG 355-1 Repaired Signal Equipment. Depot Inspection Standard for TB SIG 355-2 Refinishing Repaired signal Equipment. Audio Oscillator TS-421/U TM 11-2649 (Hewlett-Packard Model 205 -AG). Frequency Meter JW/USMTM 11-5057 26.
By Order of the Secretary of the Army: Official: J. C. LAMBERT, Major General, United States Army The Adjutant General.
TM 11-6625-496-45 Technical Manual No. 11-6625-496-45 HEADQUARTERS, DEPARTMENT OF THE ARMY WASHINGTON 25, D. C., 3 ]uly 1962 TEST SET, RADIO AN/VRM-1 Paragraph C HAPTER 1 . C HAPTER 2 . Section I. II. III. IV. v. C HAPTER 3 . Section I. II. APPENDIX INDEX THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FOURTH ECHELON MAINTENANCE General troubleshooting techniques . . . . . . . . . . . . . . . . . . . . . Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 1 THEORY 1. Scope a. T h i s m a n u a l c o v e r s f i e l d ( f o u r t h echelon) and depot mainteriance for Test Set, Radio AN/VRM-l. It includes instructions appropriate to fourth and fifth echelon for troubleshooting, testing, aligning, and repairing the equipment. Detailed functions of the AN/VRM-1 are covered in this chapter. b. The complete technical manual for this equipment includes TM 11-6625-49612, TM 11-6625-496-20P. and TM 11-662545P. c.
S7902E. The 16 volts dc is supplied to the audio amplifier or one of the rf amplifiers and the test probe rf preamplifier from S7902E. 3. Audio Amplifier (fig. 1) The audio amplifier is a three-stage, direct-coupled, class A amplifier. Power, input, and output connections to the audio amplifier are completed when the selector switch S7902 is in position 3, 4, 5, 6, 10, or 11. The output from the audio amplifier is rectified and fed to the Schmitt trigger circuit. a.
Figure 1. Audio amplifier, schematic diagram. (1) Transistor Q7602 receives its input from the secondary winding of T7602. The input signal is coupled to the base of transistor Q7602 through capacitor C761O. (2) The output signal of Q7602 is developed across a tuned circuit consisting of inductor L7603 and capacitor C7612. Resistor R7609 reduces the Q of the tuned circuit to provide the proper bandwidth.
Figure 2. Amplifier, 11.6-mc, schematic diagram. 6. Amplifier, 5.65-Mc (fig. 3) The 5.65-mc amplifier is a singlestage if. amplifier which has a gain of about 15 db. Power, input, and output connections are made to the 5.65-mc amplifier when selector switch S7902 is inposition 12, 15, 16, or 17. The output from the amplifier is rectified and fed to the Schmitt trigger circuit. a.
portion of the emitter-base bias and stabilizes the emitter current. Capacitor C7703 is an rf bypass capacitor. Capacitor C7702 and inductor L7701 form a decoupling network in the +16-volt dc supply line. c. The output from the 5.65-mc amplifier is rectified by diode CR7701 and filtered by capacitor C7705. The dc output is taken from potentiometer R7708 and fed to the Schmitt trigger circuit. The amount of dc output voltage to the Schmitt trigger can be varied by adjustment of R7708. 7. Amplifier, 47.
voltage divider which provides the fixed-hissing portion of emitterbase bias for Q7703. Resistor R7714 develops the self-biasing portion of the emitter-base bias and stabilizes the emitter. Capacitor C7711 places the base of Q7703 at rf ground potential. Capacitor C7716 and inductor L7703 form a decoupling network in the +16-volt dc supply line. c. The output from the second 47.0-mc amplifier is rectified by diode CR7702. The rectified signal is filtered by capacitor C7714.
47.0-mc amplifier; diode CR7402, with the 11.5-mc amplifier; and diode CR7403, with the 5.65-mc amplifier. The diode associated with the rf amplifier in use conducts to allow +16 volts to be supplied to the test probe rf preamplifier. The two diodes associated with the two rf amplifiers not in use prevent the supply voltage from being fed to the amplifiers from their common connection in the test probe rf preamplifier supply line. 9. Voltage Supply Limits Sensing Circuit (fig.
low-resistance path to them. When transistor Q7801 is biased into conduction, it provides a much lower path to ground than the diode network, and the diode network is effectively removed from the circuit. 10. Schmitt Trigger Circuit (fig.7) The Schmitt trigger circuit consists of a dc amplifier, a Schmitt trigger, a dc switch, and a pair of indicator lamps. The circuit is used in all positions of selector switch S7902. a. Transistor Q7802 is an emitter-follower, dc amplifier.
Figure 7. Schmitt trigger circuit, schematic diagram. a. Resistor R7817 and rheostat R7816 form a voltage divider. Rheostat R7816 is adjusted SO that the minimum source voltage will cause the line voltage sensing circuit to function. Transistor Q7806 is a unijunction transistor. When the p o w e r source voltage is below minimum, the +16 volts dc applied at base B2 of Q7806 biases it to cutoff.
Figure 8. Line voltage sensing circuit, schematic diagram. diode CR7901 is also applied through terminal B of connectors J7907 and P7801 to the line voltage sensing circuit consisting of resistors R7817, R7818, and R7819, rheostat R8716, capacitor C7802, unijunction transistor Q7806, and dc switch CR7803. The operation of this circuit is explained in paragraph 11. c.
under test or the TS-1777/VRM-l 16-volt line can be tested. a. When the TS-1777/VRM-l 16-volt line is tested, the test probe tip is inserted in test jack A. The regulated output of the +16-volt dc regulator circuit is applied through rf choke L7301 and level-adjusting rheostat R7501 to the voltage supply limits sensing circuit. The output from this circuit is applied to the Schmitt trigger circuit. If the regulated voltage is within limits, GREEN indicator lamp. D67902 lights.
F i g u r e 9 . T e s t s in selector switch positions A, 2, 3, and 7, simplified schematic d i a g r a m .
minimum limit, GREEN indicator DS7902 will light. If the signal voltage is below the minimum limit, insufficient voltage will be applied to the Schmitt trigger circuit, and RED indicator DS7901 will light. Operating voltages are supplied to the 11.5-mc amplifier and Schmitt trigger circuit from the +16-volt dc regulated line. Operating voltage is supplied to the test probe rf preamplifier from the +16-volt dc regulated line through diode CR7402 and rf choke L7501. 18. Selector Switch Position 8 (A, fig.
Figure 10. Tests in selector switch positions 8, 12, 13, 16, and 18 simplified schematic diagram.
probe rf preamplifier is fed through coupling capacitor C7901 and attenuating resistor R7911 to the 5.65-mc amplifier. The rectified output of the 5.65-mc amplifier is applied to the Schmitt trigger circuit. If the signal voltage is above the minimum limit, GREEN indicator DS7902 will light. If the signal voltage is below the minimum limit, insufficient voltage will be applied to the Schmitt trigger circuit, and RED indicator D67901 will light. Operating voltage for the 5.
CHAPTER 2 FOURTH ECHELON MAINTENANCE Section I. GENERAL TROUBLESHOOTING TECHNIQUES Warning: When servicing the TS-1777/VRM-1, be careful when working near power connections. Injury may result from contact with these connections. 28.
chart (para 34) and the schematic diagram (fig. 39) to find normal readings, and compare them with readings taken. (2) Intermittent troubles. In all these tests, the possibility of intermittent troubles should not be overlooked. If present, this type of trouble often may be made to appear by tapping or jarring the equipment. Check the wiring and the connections to the AN/VRM-l. 30.
to the AN/VRM-l. Connect the AN/VRM-l as follows: (1) Connect Mounting MT-1029/VRC to the output of the PP-2309/U; use the CX-4720/VRC. Connect the black lead of the CX-4720/VRC to the negative OUTPUT terminal of the PR-2309/U. (2) Plug the three-terminal connector of the CX-7899/VRM-l into J24 of the MT-1029/VRC. (3) Connect the four-terminal connector of the CX-7899/VRM-l to the POWER connector of the AN/ VRM-1. Note: If Power Supply PP-2309/U is not available, use an equivalent power source.
para 34. para 34. para 36. para 37. para 43.
34.
or resistors between S7902A and S7902B are defeotive. a. use the wiring diagram (fig. 11) and oheck for broken jumper leads between switch oontacts and between decks. Check also for oold solder joints, or large masses of solder whioh maybe shorting two contacts together. Cheek for open or shorted switch oontacts. b. Use the ohart below and oheck S7902A and S7902B for open resistors or for resistors with ohanged values. Remove all 22 plug-in assemblies (para 37) before measuring resistances.
Figure 11.
Section III. REPAIRS 35. General Parts Replacement Techniques All the parts of Test Set, Radio AN/ VRM-1 can be reached and replaced easily without special procedures. The following precautions apply specifically to the AN/ VRM-1. a. Use a pencil-type soldering iron with a 25-watt maximum capacity. The AN/ VRM-1 contains semiconductor devices and is transistorized. If the iron must be used with ac, use an isolating transformer between the Iron and the ac line.
make sure that the captive screws on the front panel line up with the holes In the gasket and the screw holes in the ease. (3) Tighten the eight captive screws. careful not to damage connector pins. (2) Secure the plug-in assembly use the four screws (a(2) above). (3) Replace the front panel and chassis in the ease (pare 36b). 37. Removal and Replacement of Plug-in Assmblies (fig. 12 and 13) a. Removal.
b. Replacement of Chassis Bottom Plate (fig. 12 and 14). (1) Place the chassis bottom plate in position so that the two studs on switch S7902 extend through the holes prodded and secure them: use the two nuts (a(3) above). (2) Replace and tighten the two 6-32 screws (a(2) above). (3) Replace and tighten the four 4-40 screws (a(l) above). c. Removal of Connector J7902 (fig. 12 and 14) . (1) Remove the chassis bottom plate (a above).
(2) Secure switch S7901; use the nut and lockwasher (k(3) above). (3) Reconnect the two wires (k(2) above) . (4) Replace the chassis cover plate (b above). m. Removal of Connectors J7907, J7904, J7903, J7906, and J7905 (fig. 14 and 15). (1) Remove the chassis bottom plate (a above). (2) Remove and tag wires from the terminals of the connector being removed (11 for J7907, 7 for J7904, 9 for J7903, 4 for J7906 and 8 for J7905). (3) When removing J7903, remove two locating pins, two lockwashers, and two nuts.
(2) Unsolder and remove the 26 leads and one lead of capacitor C7901 from S7902; tag each lead as it is removed (fig. 14). (3) Remove the screw, knob, nut, and lockwasher from the front panel front side of the switch (fig. 13). (4) Remove the S7902 from the rear side of the front panel. v. Replacement of Switch S7902. (1) Insert the shaft of S7902 through the rear of the front panel, with contacts A and 20 uppermost; be careful to seat the locating lug in the hole provided in the front panel (fig. 13).
Figure 15. Test Set, Radio TS-1777/VRM-1 front panel chassis, top v i e w . x. Replacement of Resistors Mounted on switch S7902. (1) Cut the resistor leads to the proper length and make a good mechanical connection at the solder lugs of switch S7902. (2) solder the resistor 1 e a d to the solder lugs of switch S7902. Be careful not to damage or drop solder into the contacts of switch S7902. 39. Removal and Replacement of Case Gasket (fig. 18) a. Removal. Remove the gasket by peeling it off the case face.
Figure 16. Teat Set, Radio TS-1777/VRM-l front panel and chassis. left view. b. Replacement of Test Probe cable (fig. 15 and 19). (1) Insert the probe cable end through the coupling nut, washer, and grommet (a(4) above). (A new grommet should be used if available.) (2) Connect and solder the inner cable conductor to terminal E7912. (3) Connect and solder the inner shield to the ground lug on connector J7904. (4) Connect the outer shield to terminal E7903.
breaks in the cables near this connector. Figure 20 is a cable wiring diagram and exploded view of the CX-7899/VRM-l. (a) Disassemble the 18-terminal connector as follows: (a) Remove four screws. (b) Remove the connector shell. (c) Remove the connector c1amp from the female connector. (3) Reassemble the 18-tertinal connector as follows: (a) Place the cables in the grooves provided in the connector shell. (b) Slide the connector clamp over the cables and under the female connector.
Figure 19. Test probe cable, disassembled. Figure 20. Cable Assembly, Specail Purpose, E l e c t r i c a l B r a n c h e d C X - 7 8 9 9 / V R M - l , partially disassembled and schematic diagram.
Section IV. FINAL ADJUSTMENTS 41. General Final adjustment of the TS-1777/VRM-l must be performed after major repair, parts replacement, or extensive alignment of individual plug-in assemblies. The final adjustment procedures can also be used as a quick check to see if the TS-177/ VRM-1 circuits are properly adjusted. 42. Test Equipment and Special. Tools Required a. The following chart lists test equipment required for final adjustment of Test Set, Radio AN/VRM-l.
Figure 21. Fabrication of special test cables. (3) Use the Transistor Power Supply 721A and apply +5 volts dc to the test probe. (4) Measure the voltage at connector P7801-H with the ME-26B/U; adjust potentiometer R7803 for approximately +0.5 volt dc. (5) Measure the voltage of the emitter of transistor Q7801 (ungrounded side of potentiometer R7801) with the ME-26B/U; adjust potentiometer R7801 for approximately +1 volt dc . (6) Measure the 721A output with the TS443/U; increase the output to 13.
O volt dc; then slowly increase it. Observe the voltage on the TS443/U when a sudden drop in the voltage measured by the ME-26B/ U indicates G R E E N indicator DS7902 has switched on and a sudden rise in voltage indicates GREEN indicator DS7902 has switched off. The GREEN indicator should switch on when the ME443/U indicates 10.5 volts and switch off at 13.0 volts. (11) If necessary, readjust potentiometer R7803 and R7801 to assure the conditions given in (10), above. d. DC Circuits (fig. 33).
drop in voltage measured by the ME-26B/U indicates that GREEN indicator DS7902 has switched on. The 411A should idicate 220 (8) If necessary, readjust R7708 to assure the condition given in (7) above. g. Circuits 11.5-mc (fig. 22 and 33). ( 1 ) Reduce the 606A output to 0 volt dc. (2) Turn the TS-1777/VRM-l selector switch to position 14. (3) Adjust the 606A for an output of 11.5 mc at 14 mv as indicated by the 411A.
Figure 23. Section V. FOURTH ECHELON TESTING PROCEDURES 44. General a. Testing procedures are prepared for use by Signal Field Maintenance Shops and Signal Service Organizations responsible for fourth echelon maintenance of signal equipment to determine the acceptability of repaired signal equipment. These procedures set forth specific requirements that repaired signal equipment must meet before it is returned to the using orgauzation. A summary of the performance standards is given in paragraph 52. b.
Fig.
46.
40 Figure 24.
47.
42 Figure 25.
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46 Figure 26.
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Figure 27.
50. 11.5 -Mc Amplifier Tests Figure 27 Fig.
52 Figure 28.
51. 47.0-Mc Amplifier Test Figure 28. fig.
52. Summary of Test Data Personnel may find it convenient to arrange data in a manner similar to that 54 shown below. An “X’ in the Indicator column indicates the indicator designated is lighted.
CHAPTER 3 FIFTH ECHELON MAINTENANCE Section I. TROUBLESHOOTING AND REPAIR 53. General This chapter includes troubleshooting and repair procedures to be performed by fifth echelon maintenance facilities. It includes detailed isolation, replacement, and adjustment data for the plug-in assemblies. Chapter 4 includes fifth echelon final testing procedures. 54. Plug-In Assembly Repair Procedures a. General. The plug-in assembly repair procedures direct the isolation and repair of trouble in these assemblies.
near normal operations encountered, faully parts isolation procedure will be specified. The test results, which are recorded i n various test steps, are compared to a normal indication. All of the conditions included must be satisfied before a normal indication has occurred. If a normal indication is obtained in the first test, the second test will be performed. This process continues, with successive normal indications, until the final test normal indication is obtained.
(3) Adjust the TS-382F/U frequency to 100 cps while maintaining an ME30 B/U indication of 50 mv. A normal indication should be +1.5 volts dc ±0.4. (4) Adjust the TS-382F/U frequency to 3,000 cps while maintaining an ME30 B/U indication of 50 mv. A normal indication should be +3.0 volts dc ±0.4. (5) If the indications obtained in (3) and (4) above are normal, trouble isolation is complete. (6) If the indications obtained in (3) or (4) above are low, proceed to d below. d. Isolation.
Figure 29. Assembly A7400, parts location.. (5) Move the 411A to connector P7501C and P5701-D. The normal indication should be less than 3 db trouble isolation in assembly A7500 is complete. 57. Isolating Troubles in Assembly A7600 (6) Move the 411A to connector P7501M and P7501-L and adjust the 666A output frequency to 5.6446 mc ±100 cps as indicated by the AN/USM-26 and for a 0-db indication on the 411A. (7) Move the 411A to connector P7501C and P7501-D.
Figure 30. Assembly A 7600, parts location maximum indication on the ME-26B/U and record the indication. (4) Increase the 606A output to 20 mv as indicated on the 411A. Record the ME-26B/U indication. (5) A normal indication, noted in (3) above, should be +4.0 volts dc (6) A normal indication, noted in (4) above, should be + 5.5 volts dc minimum. (7) If the indications obtained are low or absent, proceed to d below. c. Bandwidth Test. (1) Adjust the 606A for a 411A indication of 10 mv.
(a) Signal voltage chart. Circuit junction Signal voltage (rms) I P7601-C C7601 and T7601 T7601 and C7603 Q7601 base T7602 and C7609 R7605 and R7606 T7602 and C7610 Q7602 base Q7602 collector R7606 and C7611 4.9 3.0 5.7 5.6 5.6 17.0 33.0 34.0 2.5 27.5 mv mv mv mv mv mv mv mv v mv (b) Dc voltage chart. Circuit junction P7601-H C7604 and R7603 Q7601 base Q7601 emitter R7605 and R7606 Q7602 base Q7602 emitter R7608 and C7611 CR7602 and R7611 P7601-K +dc voltage to ground (volts) 15.3 16. 3 5.35 5.
(a) Signal voltage chart. Circuit junction Signal Voltage (rms) P7701-M R7703 and c7701 Q7701 emitter Q7701 collector 81mv 15.55 mv 17.5 mv 1.75 v (b) DC voltage chart. Circuit junction P7701-L L7701 and C7702 Q7701 emitter Q7701 base CR7701 and R7708 P7701-J +dc Voltage to ground (volts) 16.0 14.8 6.95 6.75 2.9 (rectified signal) 2.0 (rectified Signal) (3) Remove the test signal and set the TS-1777/VRM-1 ON-OFF switch to OFF. (4) Replace the faulty part. (5) Repeat b and c above. e.
(b) Dc voltage chart. Circuit junction I P7701-D C7710 and R7913 Q7702 base Q7702 emitter R7912 and R7913 Q7703 collector Q7703 base Q7703 emitter P7701-F +dc voltage to ground (volts) 15.2 15.15 6.2 6.5 7.25 16.1 7.45 6.7 200 (rectified signal) (3) Remove the test signal and set the TS-1777/VRM-l ON-OFF switch to OFF. (4) Replace the faulty part. (5) Repeat f and g above. 59. Isolating Trouble in Assembly A7800 Refer to figure 39 for circuit details and figure 33 for aid in locating the parts. a.
e. Voltage Supply Limits Sensing Circuit Test. (1) Perform the alignment procedure for the voltage supply limits sensing circuit (para 43 c). (2) If the circuit does not adjust properly. Prooceed to f below. (9) If the circuit does adjust properly, trouble Isolation In assembly A7800 is complete. f. Voltage Supply Limits Sensing Circuit Isolation. (1) Adjust the 721A for an output voltage of +12 volts dc and apply it to the test probe.
Figure 32.. Assembly A 7700, parts location.
Figure 33. Assembly A 7800, parts Location. Section II. FIFTH ECHELON TESTING PROCEDURES 60. Purpose of Final Testing The tests outlined in this section measure the performance capability of a repaired TS-1777/VRM-l. Equipment that meets the minimum standards stated in the tests will furnish satisfactory operation equivalent to that of new equipment. 61. Test Equipment Required for Final Testing The test equipment required for final testing is the same as that listed for fourth echelon testing (para 45).
63. Power Tests Check the ability of the TS-1777/VRM-l to test power circuits as directed below. a. Preparation. (1) Insert the test probe tip in test jack A, turn the selector switch to A, and check to be sure that the GREEN indicator lights. (2) Connect the output of the 721A to the test probe b. Dc Test, +16- Volt. (1) Turn the selector switch to A. (2) Increase Transistor Power Supply 721A output voltage. (a) The RED indicator should light before +7.0 volts is reached.
ME-30B/U. The RED indicator should be lighted. (3) Increase the audio output of the TS382 F/U to 6.4 volts. The GREEN indicator should be lighted. 65. Amplifier Tests, 5.65-Mc (fig. 34) Check the ability of the TS-1777/VRM-l to test 5.65-mc amplifier circuits as directed below. a. Preparation. (1) Insert the test probe tip in test jack A, turn the selector switch to A, and check to be sure that the GREEN indicator lights. (2) Connect the output of Hf Signal Generator 606A adjusted to 5.
Figure 34. Test Set, Radio AN/VRM-1, final tests, block diagram. 411A. The RED indicator should be lighted. Increase the rf output of the 606A to 0.014 volt. The GREEN indicator should be lighted — 67. Amplifier Test, 47.0-Mc (fig. 34) check the ability of the TS-1777/VRM-l to test the 47.0-mc amplifier circuit as directed below. a. Preparation. (1) Insert the test probe tip in test jack A, turn the selector switch to A, and check to be sure that the GREEN indicator lights.
APPENDIX REFERENCES The following is a list of applicable references available to the field and depot maintenance repairmen of Test Set Radio AN/VRM-l. DA Pam 310-4 TA 11-17 TA 11-100(11-17) TM 11-2684 TM 11-5057 TM 11-5820401-10 TM 11-5820401-20 TM 11-6625-200-12 TM 11-6625-261-12 TM 11-6625-320-12 TM 11-6625414-10 TM 11-6625496-12 TM 11-6625-496-20P TM 11-6625-496-45P Index of Technical Manuals, Technical Bulletins, Supply Bulletins, Lubrication Orders, and Modification Work Orders.
COLOR CODE MARKING FOR MILTARY STANDARD RESISTORS Figure 35.
INDEX Paragraph Adjustments, circuit: Audio ------ ------ ------ ----DC ------- ------- -----------11.5-mc--------------------5.65-mc --------------------47.0-mc --------------------Voltage supply limits sensing--Aligment Equipment required ----------General --------------- ------procedures ------- ------- ---Amplifier: 5.65-mc: Tests - - - - - - - - - - - - - - - - - - - Theory ------------------11.5-mc: Tests ------------ ------ -Theory ------------------47.
Paragraph Page 38 c 26 Connector J7902 ---—-— -----38 m 27 Connectors -----—-—-——-—38o, q 27 Diodesa --------- -- —-—--— 36 a 24 Front panel -- — --— -—-——38 g 26 Fuseholder ------——-——39a c 29 Gasket ---------—-———-—38 e 26 Lamp socket 37 a 25 Plug-in assemblies ——— 38o, w 27,28 Resistors ---------———— 38 k switch S7901 ---—— 26 38 u switch S7802 - - - - - — — — — 27 38 i 26 Test jack — - - - - — — — — — 40 a 28 Test probe cable ------———-40 c Repair, CX-7899/VRM-1——-— 20 54 55 Repairs, plug-in assemblie
By Order of Secretary of the Army: G. H. DECKER, General, United States Army, Chief of Staff Official: J. C. LAMBERT, Major General, United States Army, The Adjutant General.
020804
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