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E.F. Johnson Company 761X - page 1
First Printing No v emb er 1998 761x (VHF) 764x (UHF) Con ventional Mobile VHF 146- 174 MHz 45 W atts P ar t No . 242-76 10-0 x x UHF 400-4 30, 45 0-470, 4 70-490 , 490-5 12 MHz 35 W atts P ar t No . 242-76 40-0 x x Service Manual ...
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E.F. Johnson Company 761X - page 2
761x (VHF) 764x (UHF) CONVENTIONAL FM TW O-W A Y RADIO VHF 146-174 MHz 45 W atts UHF 400-430, 450-470, 470-490, or 490-512 MHz 35 W atts Copy ri ght© 1998 by T ranscr y pt Inter nat ional Incor porat ed T ransc r ypt offers communic ation sol utions i n two core area s: la nd mobi le radio prod ucts and syst ems, and informat ion s ecur ity . EFJo ...
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E.F. Johnson Company 761X - page 3
T ABLE OF CONTENTS ii November 19 98 Part No. 0 01-7600- 001 1 GENERAL INFORMATION 1.1 SCOPE OF MANUAL . . . . . . . . . . . . . . . . . . . .1-1 1.2 TRANSCEIVER DE SCRIPTION . . . . . . . . . . .1-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1.3 PRODUCT WARRANTY . . . . . . . . . . . . . . . . .1-1 1.4 PART NUMBER ...
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E.F. Johnson Company 761X - page 4
T ABLE OF CONTENTS (CONT’D) iii Novembe r 1998 Part No. 0 01-7600- 001 4.5 UNIQUE PMR (EUROPEAN) SCR EENS . . 4 -1 5 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 5 Unique PMR Screens . . . . . . . . . . . . . . . . . . . . 4-15 4.6 CLONING (PROGRAMMING ONE TRANSCEIVER WITH ANOTHER) . . . . . 4-16 5A VHF (76 10) CIRCUI ...
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E.F. Johnson Company 761X - page 5
T ABLE OF CONTENTS (CONT’D ) iv November 19 98 Part No. 0 01-7600- 001 8 SCHEMATIC DIAGRAMS AND COMPONENT LAYOUTS VHF (761x) Mod els Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1 Transistor and Diode Ba sing . . . . . . . . . . . . . . . . .8-2 Main Unit Boar d Bottom View. . . . . . . . . . . . . . .8-3 Main Unit Boar d, ...
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E.F. Johnson Company 761X - page 6
1-1 Nove mber 1998 Part No. 0 01-7600- 001 GENERAL INFORMA TION SECTION 1 GE NERAL INFORMA TION 1.1 SCOPE OF MAN U AL This ser vice manual conta ins opera tion, inst alla- tion, pr ogram min g, a lignm en t, an d se rvice inf orma tio n for the EFJohnso n® 7610 and 76 40 mobile t ransce iv- ers . 1.2 TRANSCEIVER DESCRIPTION 1.2.1 GENERAL The 7600- ...
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E.F. Johnson Company 761X - page 7
GENERAL INFORMATION 1-2 November 19 98 Part No. 0 01-7600- 001 5:30 PM. Cent ral T ime, Monday - Frida y . The Customer Se rvice Depa rtment can be reache d using one of t he followi ng telepho ne numbers: T oll-Fre e: (800) 328-391 1 (From wi thin cont inental United Sta tes on ly) Internat ional: (507) 835-691 1 F AX: (507) 835-6 969 E-M a il: F ...
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E.F. Johnson Company 761X - page 8
GENERAL INFORMATION 1-3 Nove mber 1998 Part No. 0 01-7600- 001 Return Aut horizat ion (RA) number s are not nec- essary unless you have bee n given one by the Fiel d Service Department . RA numbers are require d for exchange units or i f the Fi eld Servic e Depar tment wants to be aware of a speci fic prob lem. If you have been give n an RA number ...
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E.F. Johnson Company 761X - page 9
GENERAL INFORMATION 1-4 November 19 98 Part No. 0 01-7600- 001 This pag e inte ntionall y left blan k. ...
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E.F. Johnson Company 761X - page 10
GENERAL INFORMATION 1-5 Nove mber 1998 Part No. 0 01-7600- 001 7610 (VHF) AND 7640 (UHF) MOBILE SPECIFICA TIONS The fo llowing ar e general speci ficati ons inten ded for use in te sting and servi cing this trans ceiver . For curren t adverti sed speci fica tions, re fer to t he spec ificati on sheet a vaila ble from yo ur sales repre sentativ e. V ...
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E.F. Johnson Company 761X - page 11
GENERAL INFORMATION 1-6 November 19 98 Part No. 0 01-7600- 001 NOTES ...
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E.F. Johnson Company 761X - page 12
2-1 Nove mber 1998 Part No. 0 01-7600- 001 INST A LLA TION AND DISASSEMBL Y SECTION 2 INST ALLA TION AN D DISASSEMBL Y Figure 2-1 Installati on Components Optional Acces sory Cable P . N. 585-7600-027 DB-9 F emale Optional Exte r nal Speak er P . N. 250-0151-010 10-Ft. P owe r Cab le Red (+) Blac k (–) 20A Fuses External Spkr Jac k UHF-T ype Ant ...
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E.F. Johnson Company 761X - page 13
INSTALLATION AND DI SASSEMBLY 2-2 November 19 98 Part No. 0 01-7600- 001 Figure 2-2 Mounting Brac ket Install ation WA R N I N G • Do not mount the transce iver where it ma y inter- fere w ith th e ope rati on of v ehi cle co ntr ols. • Do not mou nt the t ransceiver whe re the use r can- not easi ly reach the co ntrols an d view the display . ...
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E.F. Johnson Company 761X - page 14
INSTALLATION AND DI SASSEMBLY 2-3 Nove mber 1998 Part No. 0 01-7600- 001 2. Route the re d and black wires fr om the tran sceiver to the bat te ry . Co nne ct the red wi re to t he p ositiv e (+) t er mina l an d the b la ck w ire to t he n egati ve (– ) term inal. 3. Plug the cable into the pigt ail coming f rom the trans - ceiver and rec onnect ...
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E.F. Johnson Company 761X - page 15
INSTALLATION AND DI SASSEMBLY 2-4 November 19 98 Part No. 0 01-7600- 001 2.6 TRANSCEIVER DISASSEMBL Y Removing Bot tom Cover and F ront Panel 1. Remove the bot tom cove r by r emoving four scre ws (A) as sh own in Figur e 2-4. 2. Remove the front panel b y removing t wo screws (B). Figure 2-4 Cover and Front P anel Remo v al Removing PC Board 3. Re ...
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E.F. Johnson Company 761X - page 16
INSTALLATION AND DI SASSEMBLY 2-5 Nove mber 1998 Part No. 0 01-7600- 001 2.7 2-T ONE/5-T ONE MODULE INST ALLA TION 2.7.1 INSTALLATION PROCEDURE 1. Tu rn power of f and disconnec t the power cable . 2. Remove the bottom co ver by removi ng the fou r screws ( A) shown in Fi gure 2-5. 3. Install the module as sh own in Figure 2-7. The include d foam p ...
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E.F. Johnson Company 761X - page 17
INSTALLATION AND DI SASSEMBLY 2-6 November 19 98 Part No. 0 01-7600- 001 1. Monitor the t ra nsmi t si gnal with a co mmuni ca ti ons monitor . Set it fo r HPF = Of f, LPF = 20 kHz , De- emphas is = Of f, and Level = (P- P)/2. 2. Select a channe l near the ce nter of the band and turn a long tone on ( see prec eding “NOTE”) by press ing the app ...
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E.F. Johnson Company 761X - page 18
3-1 Nove mber 1998 Part No. 0 01-7600- 001 OPERA TION SECTION 3 OPERA TIO N Figure 3-1 7600 Front P anel 3.1 FEA TURES • Up to 32 cha nnels programmable • Multi- tone ( C TCSS ) and/ or Mul ti- code (CDCS S ) Call Guar d® squelc h programmabl e • VHF and UHF , wideband and narrowb and models avail abl e • Up to 45 wat ts VHF and 35 watt s ...
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E.F. Johnson Company 761X - page 19
OPERATION 3-2 November 19 98 Part No. 0 01-7600- 001 3.2 CONTRO LS AND DISPLA Y 3.2.1 F RONT P ANEL CONTROLS Power Switch ( ) - Pres s this switc h to turn powe r on and pre ss and hold it to t urn power of f. The trans - ceiver may be progr ammed so th at a passwor d must be entere d to al low operat ion. Ref er to Sect ion 3.3. 2 for more i nform ...
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E.F. Johnson Company 761X - page 20
OPERATION 3-3 Nove mber 1998 Part No. 0 01-7600- 001 then re ady to be us ed. T o turn power of f, press and hold the POWER swit ch until power turn s of f. 3.3.2 ENTER ING A P ASSW ORD The tran sceiver ma y be progra mmed so that a passwo rd must be entere d before t he transc eiver ca n be used. When power is t hen turned on, “PWORD” is displ ...
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E.F. Johnson Company 761X - page 21
OPERATION 3-4 November 19 98 Part No. 0 01-7600- 001 3.3.7 BANK SELECT T wo banks of up to 16 chann els each c an be pro- grammed. Only the channels in the cur rent bank are then s ele ctabl e. Th is wo uld al low , fo r ex amp le, gr oups of channe ls to be programmed for opera tion in di ff er- ent ci ties . The key i s pressed t o switch bet wee ...
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E.F. Johnson Company 761X - page 22
OPERATION 3-5 Nove mber 1998 Part No. 0 01-7600- 001 • Note if the busy in dicat or ( ) on the fro nt panel is bein g displaye d. If it is n ot, the channel i s not busy and a message can be transmi tt ed. • T aking the micr ophone o ff- hook disabl es coded squelch contro l if it is progra mmed for t he monit or functi on. T ake the microp hon ...
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E.F. Johnson Company 761X - page 23
OPERATION 3-6 November 19 98 Part No. 0 01-7600- 001 3.5.5 CALL GUARD T ONE SELECT If the tran sc eive r has a key , the Call Guar d (CTC SS) tone can be selec ted. T his allo ws cal ls to be pl aced to di ffe rent mobil es or grou ps of mobile s and rec eiv ed on d if ferent group s than is no rmal fo r the channel. Proceed as fo llows: 1. Press t ...
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E.F. Johnson Company 761X - page 24
OPERATION 3-7 Nove mber 1998 Part No. 0 01-7600- 001 3.5.15 SCAN LIST PROGRAMMING Pressin g the key changes the scan list st a- tus of the cu rren t cha nne l. Refe r to th e sc an list descri ption in Se ction 3.6.2 for m ore info rmatio n. 3.5.16 T ALK-AROUND SELECT The talk -aroun d mode causes transm issions t o occur on the recei ve fr eque nc ...
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E.F. Johnson Company 761X - page 25
OPERATION 3-8 November 19 98 Part No. 0 01-7600- 001 The scan l ists ar e user pr ogrammable if the key is ava ilable. P ressing t his key ch anges the status of the di splayed ch annel in t he cur rent scan list only . The dis play indi cates “SC ON” i f the cha nnel was just added to t he scan li st and “SC OF” if it was just de leted. In ...
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E.F. Johnson Company 761X - page 26
4-1 Nove mber 1998 Part No. 0 01-7600- 001 PR OGRAMMING Figure 4-1 Progr ammin g Setup F emale DB9 Plug T o Computer Progr amming Cab le (Include s Le v el Conv er t. Circuit ) Adapter Cab le P . N. 585-7600-031 P . N. 585-7500-031 4.1 GENERAL 4.1.1 PROGRAMMING SETUP The foll owing i tems are requi red to program th is transc eiver . The part numbe ...
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E.F. Johnson Company 761X - page 27
PROGRAMMING 4-2 November 19 98 Part No. 0 01-7600- 001 on the di sk cal led ADJ. The us e of this program is descri bed in Se ction 5. These ar e DOS programs, s o W indows® 3.x, 95, or NT are n ot req uired to r un them. If the pr ogram does not run pro perly in W i ndows, run it in the DOS mode. Before yo u use the p rogram, the files on the di ...
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E.F. Johnson Company 761X - page 28
PROGRAMMING 4-3 Nove mber 1998 Part No. 0 01-7600- 001 4.4.3 SCREEN MENU NOTE: The Sc r een menu for PMR ( Eur opean) models is sli ghtly di ffer ent than the LMR versi on shown above. Refer to S ection 4.5 for mor e informatio n on PMR models. Memory Channel - Disp l ays the sc reen s hown in T able 4-1 which is used t o program cha nnel para me- ...
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E.F. Johnson Company 761X - page 29
PROGRAMMING 4-4 November 19 98 Part No. 0 01-7600- 001 in the Scr ee n me nu (s e e Se ct ion 4 .4.3 ), M em or y Channel s creen (se e T able 4-1), and DTMF Autodia l screen (see T able 4-3) . PMR - Sele cts PMR (Europ ean) models . Selecti ng this mode l displa ys uniqu e paramete rs for program- ming a 5-t one optio n. As with the LMR selecti on ...
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E.F. Johnson Company 761X - page 30
PROGRAMMING 4-5 Nove mber 1998 Part No. 0 01-7600- 001 Ch Atr (Channel Attribute) Press (Enter) to display the menu which s elects one of the following choices : A: P ri o rit y A - The chan nel is selected when the Prio A key is pressed, and it is monitored during prior ity scan. In addition, the m icrophone han ger can be pr ogrammed so that th i ...
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E.F. Johnson Company 761X - page 31
PROGRAMMING 4-6 November 19 98 Part No. 0 01-7600- 001 RF PWR Programs the RF power output for the channel (High, Low1, Low2). This setting can be temporarily or perma- nently overr idden by the HIGH, LOW1, o r LOW2 powe r option sw itch if it i s program med (see T able 4-2). Locko ut T ransmit Disable On Busy . The following co nditions can be pr ...
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E.F. Johnson Company 761X - page 32
PROGRAMMING 4-7 Nove mber 1998 Part No. 0 01-7600- 001 T able 4-2 Key and Displa y Assign Screen Description KEY ASSIGN P ARAMETERS The and F1-F 4 option keys can be p rogrammed for the foll owing functi ons. P ress the (Enter) key and then PgUp/PgDn to displ ay and then select the desired functio n. Parameter Key Label Descr iption Nul l -- - No f ...
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E.F. Johnson Company 761X - page 33
PROGRAMMING 4-8 November 19 98 Part No. 0 01-7600- 001 Parameter Key Label Descr iption RF A TT A TT T oggles the receive attenu ate function on and o ff (see Se ction 3.5.13). Lock LO CK Locks/unlocks all programmable keys except CALL, MONI, and EMER to prevent them fro m being accidentally pressed (s ee Section 3.5.9). Beep BEEP T oggles the key ...
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E.F. Johnson Company 761X - page 34
PROGRAMMING 4-9 Nove mber 1998 Part No. 0 01-7600- 001 Parameter Descr iption Light En ables or di sables th e display an d key backl ight. This programming can be overri dden by the po wer-on men u (see Section 3.3.4) or LI TE key (s ee Section 3. 3.9). The “Auto ” configur ation allows it to be controlled by pin 1 of the DB9 connector on the ...
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E.F. Johnson Company 761X - page 35
PROGRAMMING 4-10 November 19 98 Part No. 0 01-7600- 001 T able 4-4 Continuous T one Screen Description Desc riptio n The continuo us tones p rogrammed in t his screen ar e selected by pressing the C.T one CH Ent function key (see T able 4-2) and then pr essing the up/down keys . This allows the user to s elect the con tinuous to ne being tran smitt ...
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E.F. Johnson Company 761X - page 36
PROGRAMMING 4-11 Nove mber 1998 Part No. 0 01-7600- 001 Parameter De scriptio n Stop Ti mer When Mode 2 or 3 above is prog rammed (priority scanning) , this sets how often in seconds the prio rity channel is checked while receiving a message on some othe r channel. Resume Tim er This sets the scan resume delay in secon ds. This is the time that ela ...
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E.F. Johnson Company 761X - page 37
PROGRAMMING 4-12 November 19 98 Part No. 0 01-7600- 001 Parameter De scripti on Beep Emits (or turns of f) the following b eeps when receiving a matched 2-tone: Null - Beep emission ( or non-emission ) is retained even when receiving a matched 2-tone. Off - Rep eater beep emission is turned of f. Pi (Single) - One high beep once. PiPi (Single) - T ...
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E.F. Johnson Company 761X - page 38
PROGRAMMING 4-13 Nove mber 1998 Part No. 0 01-7600- 001 T able 4-7 Common S creen Descri pti on Parameter De scriptio n User Password Programs the passwo rd that must be entered at power on if the fo llowing “PWR ON Password” parameter is “On” or to canc el th e “STUN” cond itio n describ ed in T able 4-6 . Any fou r-di git num ber from ...
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E.F. Johnson Company 761X - page 39
PROGRAMMING 4-14 November 19 98 Part No. 0 01-7600- 001 Parameter De scripti on Power On Password This turns th e pas sword fun ctio n o n and o f f . When it is tur ned on, “PW oRd” is displayed when power is turned on and a fou r-dig it pas swor d must b e entered to en able the transceiver ( see Section 3.3 .2) . The passwor d is pro - gramm ...
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E.F. Johnson Company 761X - page 40
PROGRAMMING 4-15 Nove mber 1998 Part No. 0 01-7600- 001 Parameter De scriptio n Emer Sw On T imer Sets the per iod in seco nds that the Emer gency function key must be p ressed to activate the emer gency f unction. An emergency call is initiated by pressi ng the Emergency key for longer than this tim e. Emer Sw Off Timer Sets the period in seconds ...
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E.F. Johnson Company 761X - page 41
PROGRAMMING 4-16 November 19 98 Part No. 0 01-7600- 001 The fo llowing sc reens sel ected in the pr eceding Screen men u are uniqu e to PMR model s. Refer t o on- line he lp for in format ion on para meters in these scr eens. Rx Code Channel - This sc reen i s show n b elow and it programs the recei ve 5-t one code i nformation . Tx Code Chan nel - ...
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E.F. Johnson Company 761X - page 42
PROGRAMMING 4-17 Nove mber 1998 Part No. 0 01-7600- 001 4. Connect the ma ster tra nsceiver to the sl ave (t ar get) transc eiver by pl ugging the cloni ng cable i nto the microphon e jack of e ach. 5. Tu rn the sl ave trans ceive r on. Then moment arily press the PO WER swit ch o f th e ma ster trans cei ve r to begin the da ta trans fer . 6. When ...
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E.F. Johnson Company 761X - page 43
PROGRAMMING 4-18 November 19 98 Part No. 0 01-7600- 001 This pag e inte ntionall y left blan k. ...
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E.F. Johnson Company 761X - page 44
5A-1 Nove mber 199 8 Part No. 0 01-7600- 001 VHF (7610) CIRCU IT DESCRIPTION NOTE: A VHF tran sceiver b lock diagr am is located on page 8- 1. 5.1 VHF RECEIVER CIRCUIT 5.1.1 ANTENNA SWITCHING CIRCUIT The anten na swit ching cir cuit fun ctions as a low- pass fi lter whil e rec eiving and a resonat or cir cuit whil e trans mitti ng. T his p reven ts ...
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E.F. Johnson Company 761X - page 45
VHF (7610) CIRCUIT DE SCRIPTION 5A-2 November 19 98 Part No. 0 01-7600- 001 Figure 5- 1 Second I F System IC3 ( VHF) Figure 5-2 A udio Switc hing and Amplifie r Circ uit (VHF) are pa rt of the qu ad ra ture dete ctor . The a udi o sign al is fed out on pin 9 (IC3) and a pplied to the AF ampl ifier circu it. 5.1.5 A UDIO A MPLIFIER CIRCUIT The AF (a ...
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E.F. Johnson Company 761X - page 46
VHF (7610) CIRCUI T DESCRIPTION 5A-3 Nove mber 199 8 Part No. 0 01-7600- 001 Part of the AF signa l from pin 9 of FM IF c ircuit IC3 is appl ied t o pin 24 of le v el c on troll er IC 5. T h is device a llows the CPU to contro l the sque lch thres hold level. T he level- controll ed out put signal on pin 23 i s applied to IC3, pin 8 which i s the i ...
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E.F. Johnson Company 761X - page 47
VHF (7610) CIRCUIT DE SCRIPTION 5A-4 November 19 98 Part No. 0 01-7600- 001 Figure 5-3 PLL Cir cuit (VHF) 5.2.5 APC CIRCUIT The APC (Automa tic Power Con trol) ci rcuit pro- tects the power ampl ifier from damage ca used by a mismatche d a nte nna l oad, an d prov ide s a s ta bl e p ower output. Detector D2 detect s forward signals, a nd D1 detect ...
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E.F. Johnson Company 761X - page 48
VHF (7610) CIRCUI T DESCRIPTION 5A-5 Nove mber 199 8 Part No. 0 01-7600- 001 The phase detector determ ines the p hase dif fer- ence bet ween the se signal s and then produce s output pulses o n pin 8 wh ich are f iltered by t he loo p filter . This fi lter cons ists of R43-R45, C60 , and C61. The outpu t of this filter is the DC con trol volt age ...
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E.F. Johnson Company 761X - page 49
VHF (7610) CIRCUIT DE SCRIPTION 5A-6 November 19 98 Part No. 0 01-7600- 001 5.4.3 VHF I/O EXPANDER IC5 (MAIN UNIT) 5.4.4 VHF P OR T EXPANDER IC11 (MAIN UNIT) 51 B M Outputs control sign al for beep mute cir- cuit Q10. High = Beep muted. 52- 54 CTDA0- CTDA2 Output port f or CTCSS/ DTCS signal s. 55 HANG Input port for the m icrophone hanger detectio ...
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E.F. Johnson Company 761X - page 50
5B-7 Nove mber 199 8 Part No. 0 01-7600- 001 UHF (7640) CIRCUIT DESCRIP TION SECTION 5B UHF (7640) CIRCUIT DESCRIPTION NOTE: The UHF tr ansceiver block dia gram is loc ated on page 8- 6. 5.5 UHF RECEIVER CIRCUIT 5.5.1 ANTENNA SWITCHING CIRCUIT The anten na swit ching cir cuit fun ctions as a low- pass f ilte r whi le re ce ivi ng an d a reso n ato ...
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E.F. Johnson Company 761X - page 51
UHF (7640) CIRCUIT DE SCRIPTION 5B-8 November 19 98 Part No. 0 01-7600- 001 Figure 5-4 Second IF System IC1 (UHF) Figure 5-5 A udio Switchi ng and Amplifi er Cir cuit (UHF) and ap plied to the lim iter ampl ifie r and quadr ature detect or . The quadr ature de tector de modulates t he audio si gnal cont ained in t he second I F signal. Com- ponents ...
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E.F. Johnson Company 761X - page 52
UHF (7640) CIRCUIT DESCRIP TION 5B-9 Nove mber 199 8 Part No. 0 01-7600- 001 Part of the AF signa l from pin 9 of FM IF c ircuit IC1 is ap plied to p in 24 of l evel contr oller IC 12. This device a llows the CPU to contro l the sque lch thres hold level. T he level- controll ed out put signal on pin 23 i s applied to IC1, pin 8 which i s the inp u ...
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E.F. Johnson Company 761X - page 53
UHF (7640) CIRCUIT DE SCRIPTION 5B-10 November 19 98 Part No. 0 01-7600- 001 Figure 5- 6 PLL Ci rcui t (UHF) 5.6.5 APC CIRCUIT The APC (Automa tic Power Con trol) ci rcuit pro- tects the power ampl ifier from damage ca used by a mismatche d antenna loa d, and provide s a stable powe r output. One diode i n D1 detect s forward signa ls and the other ...
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E.F. Johnson Company 761X - page 54
UHF (7640) CIRCUIT DESCRIP TION 5B-11 N ovembe r 1998 Part No. 0 01-7600- 001 The phase detector determ ines the p hase dif fer- ence bet ween the se signal s and then produce s output pulses o n pin 8 wh ich are f iltered by t he loo p filter . This fi lter cons ists of Q34, R180, R181, and C202- C204. The out put of thi s filt er is the DC contro ...
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E.F. Johnson Company 761X - page 55
UHF (7640) CIRCUIT DE SCRIPTION 5B-12 November 19 98 Part No. 0 01-7600- 001 5.7.5 UHF I/O EXPANDER IC12 (MAIN UNIT) 5.7.6 UHF P OR T EXPANDER IC13 ( MAIN UNIT ) 51 B M Outputs control sign al for beep mute cir- cuit Q10. High = Beep muted. 52- 54 CTDA0- CTDA2 Output port f or CTCSS/ DTCS signal s. 55 HANG Input port for the m icrophone hanger dete ...
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E.F. Johnson Company 761X - page 56
6-1 Nove mber 1998 Part No. 0 01-7600- 001 ADJUSTMENT PROCEDURE Figure 6-1 T est Setup Prog rammi ng Cab le P ar t No . 5 85-7500-03 1 T est Cable (F abr ica ted) 13.6 Vol t, 17A Power Supply Wa ttme ter Load 50 Oh m, 50W Frequ ency Monitor 4.0 Oh m Speaker Load 6.1 GENERAL 6.1.1 SUGGESTED T EST EQ UIPMENT The equip ment tha t should be used to ad ...
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E.F. Johnson Company 761X - page 57
ADJUSTMENT PROCEDURE 6-2 November 19 98 Part No. 0 01-7600- 001 Figure 6-2 Screen Displa y Example Figure 6-3 T est Cable Schematic DTCS Bal Le vel Squelch Le vel Selected Channe l Inf o RF P ower Outp ut FM De viation DTCS Balance Ref erence F requency Supply V oltage Internal T emp PLL Loc k V oltage RSSI IC5/IC12 D/A Outpu ts NOTE: The above val ...
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E.F. Johnson Company 761X - page 58
ADJUSTME NT PROCEDURE 6-3 Nove mber 1998 Part No. 0 01-7600- 001 T able 6-1 VHF T est Frequencies T est Channel Tx /Rx Fr eq (MHz) Power Call Guard Squelch Bandw idth [1] 1 174. 050 Low1 None Narrow or wide 2 146. 050 Low1 None Narrow or wide 3 160. 050 High None Narrow or wide 4 160. 050 Low2 None Narrow or wide 5 160. 050 Low1 None Narrow or wide ...
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E.F. Johnson Company 761X - page 59
ADJUSTMENT PROCEDURE 6-4 November 19 98 Part No. 0 01-7600- 001 in the uppe r par t of th e scr een is for th e cu rr ent ly select ed channel . 5. T o move the cu rsor be tween the parameters on the left side of the b ar gr aph , pres s th e ↑ ↓ arrow keys. T o change a paramet er , press the ← → , PgUp/PgDn, backspac e, or space bar keys. ...
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E.F. Johnson Company 761X - page 60
ADJUSTME NT PROCEDURE 6-5 Nove mber 1998 Part No. 0 01-7600- 001 Figure 6-4 VHF Adjustment P oints 4. Press (Enter ) again to select th e second adju st chan - nel. Key the transmitt er and adjust for t he display ed frequ enc y . Un ke y th e t ran smit ter a nd pre ss (E nter ) again t o exit thi s functi on. 6.4.2 OUTPUT P OWER ADJUST 1. Select ...
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E.F. Johnson Company 761X - page 61
ADJUSTMENT PROCEDURE 6-6 November 19 98 Part No. 0 01-7600- 001 2. Select the low power cha nnel in t he middle of the band (T est Ch. 5 - 160.050 MHz) . On th e comput er scr ee n, s croll to “M OD N ” if se ttin g na rr ow ba nd deviati on or “MOD W” if s etting wideb and deviati on. 3. Monitor the tr ansmit devi ation wit h a communica- ...
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E.F. Johnson Company 761X - page 62
ADJUSTME NT PROCEDURE 6-7 Nove mber 1998 Part No. 0 01-7600- 001 3. Co nne ct an R F sign al g enera tor to the a nten na ja ck. Set it to th e chan nel frequen cy wit h an out put mod- ulated with 1 kHz at the f ollowing de viation: W ideband (30 kHz) Models - 3.5 kHz Narrowband (12.5 kHz ) Models - 1. 75 kHz 4. Scroll to “SQL” o n the co mput ...
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E.F. Johnson Company 761X - page 63
ADJUSTMENT PROCEDURE 6-8 November 19 98 Part No. 0 01-7600- 001 UHF ADJUSTMENTS NOTE: Perfor m the pr eliminary s etup de scribed i n Section 6.2 befor e proc eeding with these adjustmen ts. 6.6 PLL ADJUSTMENT (UHF MO DELS) 1. Remove the bot tom cover by remov ing four screws. Connect a DC vo ltmete r to c heck po int CP1 sho wn in Figur e 6-6. 2. ...
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E.F. Johnson Company 761X - page 64
ADJUSTME NT PROCEDURE 6-9 Nove mber 1998 Part No. 0 01-7600- 001 Figure 6-6 UHF Adjustment P oints 6.7.4 DTCS W AV EF OR M ADJUST 1. Select the channel on the lo w end of the pro- grammed for DTCS code 007N (T est Ch. 5). 2. On the computer sc reen, scr oll to “DTCS N” if set- ting a narro w band channel or “DTCS W” if setting a wideband ch ...
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E.F. Johnson Company 761X - page 65
ADJUSTMENT PROCEDURE 6-10 November 19 98 Part No. 0 01-7600- 001 6.8 RECEIVER ADJUSTMENTS (UHF MODELS) 6.8.1 BANDPASS FILTER ADJUST 1. Select th e ch annel on t he low end of the ba nd (T est Ch. 1). 2. Connect an RF s ignal gener ator to the antenna jack . Set the o utput f or the cha nnel freq uency at a level o f 3.2 µ V (–97 d Bm), modulated ...
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E.F. Johnson Company 761X - page 66
7-1 Nove mber 1998 Part No. 0 01-7600- 001 PA R T S L I S T SECTION 7 P ARTS LIST 5HIý1Rï 'HV FULSWLRQ 3DUWý 1Rï æçìíýõ9 +)ôý0$,1ý 81,7 &ííì &HUDPý*50é ëðçý&.ýí ëí&ýèíí3 7 íëëðêäíçðæä è &ííê &HUDPý*50é ëðçý&+ýìåí- ýèíí3 7 íëëðêäíçðæä ä &íí? ...
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E.F. Johnson Company 761X - page 67
PARTS LI ST 7-2 November 19 98 Part No. 0 01-7600- 001 &íäç &HUDPLFý&ì çíåý-%ýì+ ýìíë.ð7ð$ íë ëðêäíçðíç í &íäæ &HUDPLFý&ì çíåý&+ýì+ ýìíì-ð7ð$ý íë ëðêäíçðíæ ë &íäå &HUDPLFý&ì çíåý&+ý ì+ýíçí%ð 7ð$ý íëëðêäíç ðçìè &í ...
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E.F. Johnson Company 761X - page 68
PART S LIST 7-3 Nove mber 1998 Part No. 0 01-7600- 001 &ìäë &HUDPLFý&ì çíåý-%ýì (ýìíê.ð7ð $ íëëðêäíç ðíçê &ìäé 7 DQWDOXPý(&67ì $ <ëëè5 íëëðêäíç ðçëç &ìäç &HUDPLFý&ì çíåý-%ýì &ýìíé.7ð 1 íëëðêäíç ðçìé &ìäæ &HUDPLFý&ì ç ...
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E.F. Johnson Company 761X - page 69
PARTS LI ST 7-4 November 19 98 Part No. 0 01-7600- 001 &ëäí &HUDPLFý&ì çíåý-%ýì(ýìí ê.ð7ð$ íë ëðêäíçðíç ê &ëäì &HUDPLFý&ì çíåý&+ýì+ ýéæí-ð7ð$ íë ëðêäíçðçí í &ëäë &HUDPLFý&ì çíåý&+ýì+ ýéæí-ð7ð$ íë ëðêäíçðçí í &ëäê ...
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E.F. Johnson Company 761X - page 70
PART S LIST 7-5 Nove mber 1998 Part No. 0 01-7600- 001 /ëæ &RL Oý0/)ìçí å$ýì5í.ð7 íëëðêäíçðçè ç 03ì ýìäëë ý9&2ýFDVH íëëðêäíçðæìé 03ë ýìäëë ý9&2ýFRYHU íëëðêäíçðæì ê 03ê ýëíèè ý)LOWHUý FDVH íëëðêäíçðååí 03é ýëíèè ý)LOWHUýFRYHU í ëëðêäíç ðå ...
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E.F. Johnson Company 761X - page 71
PARTS LI ST 7-6 November 19 98 Part No. 0 01-7600- 001 5íéé 5HVý(5-ê *(<-ýìííý 9ýõìíýRKPô íëëðê äíçðìêå 5íéè 5HVý(5-ê *(<-ýëëëý 9ýõëïëýNý RKPô íëëðê äíçðìèæ 5íéç 5HVý(5-ê *(<-ýìíêý 9ýõìíý NýRKPô íëëðê äíçðìçê 5íéæ 5HVý(5-ê *(<-ýìíëý 9ýõì? ...
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E.F. Johnson Company 761X - page 72
PART S LIST 7-7 Nove mber 1998 Part No. 0 01-7600- 001 5ìèé 5HVý (5-ê*(< -ýìíéý 9ý õìííý NýR KPô íëëðêäíç ðìæè 5ìèè 5HVý(5-ê *(<-ýìíêý 9 ýõìíý NýRKPô íëëðê äíçðìçê 5ìèç 5HVý (5-ê*(< -ýçåéý 9ý õçåíý NýR KPô íëëðêäíç ðìåê 5ìèæ 5HVý(5-ê *(<-ýìë ...
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E.F. Johnson Company 761X - page 73
PARTS LI ST 7-8 November 19 98 Part No. 0 01-7600- 001 5ëèë 5HVý(5-ê *(<-ýìèêý 9ýõìèý NýRKPôý íë ëðêäíçðìç è :ì -XPSHUý(5 '6ë7í íëëðê äíçðåææ :ç -X PSHUý (5- ê*(ý- 3: ý9 í ëëð êäíçð ìåè :æ &DE OHý2 3&ðéè ê íëëð êäíçð åæå ;ì &UVW DOý&5ðèæè ...
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E.F. Johnson Company 761X - page 74
PART S LIST 7-9 Nove mber 1998 Part No. 0 01-7600- 001 &íêì &HUDPLFý&ì çíåý-%ýì +ýìíë. ð7ð$ íëëðêäíç ðíçí &íêë &HU DPLFý &ìçíå ý&+ý ì+ýë5è %ð7ð$ý õéííðéêí ý0+]ô íëëðêäíç ðíæì &HUD PLF ý&ìçí åý&+ýì +ýì 5è% ð7ð$ý õéèíðéæí ...
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E.F. Johnson Company 761X - page 75
PARTS LI ST 7-10 November 19 98 Part No. 0 01-7600- 001 &íäé &HU DPLFý+0çí 6-ý&+ýí êí'ýèíí 9ý õéííðéêí ý0+]ô íëëðêäíç ðäêë &HUDPLFý+0çí6-ý&+ýíçí'ýèíí9ý õéèíðéæí ý0+]ô íëëðêäíç ðäêí &HUDPLFý+ 0çí6-ý&+ý íéí&ýè íí9ý õéæí? ...
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E.F. Johnson Company 761X - page 76
PART S LIST 7-11 Nove mber 1998 Part No. 0 01-7600- 001 &ìèí &HUD PLFý&ìçíå ý8-ýì+ýìí í'ð7ð$ý õéííðéêí ý0+]ô íëëðêäíç ðäìë &HUDPLFý&ì çíåý8-ý ì+ýíåí'ð7ð $ý õéèíðéæí ý0+]ô íëëðêäíç ðäíå &HUDPLFý&ì çíåý8-ý ì+ýìèí- ð7ð$ý õ ...
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E.F. Johnson Company 761X - page 77
PARTS LI ST 7-12 November 19 98 Part No. 0 01-7600- 001 &ëëä &HUDPLFý&ì çíåý-%ýì+ ýìíë.ð7ð$ íë ëðêäíçðíç í &ëêí &HUDPLFý&ì çíåý-%ýì+ ýìíë.ð7ð$ íë ëðêäíçðíç í &ëêì &HUDPLFý&ì çíåý-%ýì+ ýìíë.ð7ð$ íë ëðêäíçðíç í &ëêë &H ...
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E.F. Johnson Company 761X - page 78
PART S LIST 7-13 Nove mber 1998 Part No. 0 01-7600- 001 &êëç &HUDPLFý&ì çíåý&+ý ì+ýéæí- ð7ð$ íëëðêäíç ðçíí &êëæ &HUDPLFý&ì çíåý&+ý ì+ýéæí- ð7ð$ íëëðêäíç ðçíí &êëå &HUDPLFý&ì çíåý&+ý ì+ýéæí- ð7ð$ íëëðêäíç ðçíí &? ...
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E.F. Johnson Company 761X - page 79
PARTS LI ST 7-14 November 19 98 Part No. 0 01-7600- 001 /íë &RLOý/$ðêå ëýõéäíðèì ëý0+]ýRQOô íë ëðêäíçðäè ë &RLOý/$ ðëêëýõRWKHUýE DQGVô íë ëðêäíçðäè ì /íê &RL Oý/$ðêåë íë ëðêäíçðäè ë /íé &RLOý êê&6ð< çèè/ <ðíë0 3êý õéäíð èìëý0+]ý ...
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E.F. Johnson Company 761X - page 80
PART S LIST 7-15 Nove mber 1998 Part No. 0 01-7600- 001 4êæ 7 UDQVLVWRUý'7&ìé é(8ý7ìíæ íëëðêäíçðíêå 4êå 7 UDQVLVWRUý'7&ìé é(8ý7ìíæ íëëðêäíçðíêå 4êä 7 UDQVLVWRUý'7&ìé é(8ý7ìíæ íëëðêäíçðíêå 4éí )(7ýë6- ìééð*5ý õ7(åè5ô íëëðê äíçðææê 4? ...
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E.F. Johnson Company 761X - page 81
PARTS LI ST 7-16 November 19 98 Part No. 0 01-7600- 001 5íæé 5HVý(5-ê *(<-ýëëìý 9ýõëëíýýR KPô íëëðêäíç ðëåå 5íæè 5HVý(5-ê *(<-ýìíìý 9ýõìííýýR KPô íëëðêäíç ðìéê 5íæç 5HVý(5-ê *(<-ýëëíý 9ýõëëýýRK Pô íëëðêäíç ðçåè 5íææ 5HVý(5-ê *(<-ýêêëý 9ý? ...
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E.F. Johnson Company 761X - page 82
PART S LIST 7-17 Nove mber 1998 Part No. 0 01-7600- 001 5ìçå 5HVý (5-ê* (<-ýì íéý 9ýõìí íýNý RKPô íëëðê äíçðìæ è 5ìçä 5HVý(5-ê *(<-ýìíëý 9ýõìýNýRKPô íëëðê äíçðìèé 5ìæí 5HVý(5-ê *(<-ýçåëý 9ýõçïåýNýRKPô íëëðê äíçðìçë 5ìæë 5HVý(5-ê *(<-ýì íêý9 ...
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E.F. Johnson Company 761X - page 83
PARTS LI ST 7-18 November 19 98 Part No. 0 01-7600- 001 5ëæì 5HVý(5-ê *(<-ýìíêý 9ýõìíý NýRKPô íëëðê äíçðìçê 5ëæë 5HVý(5-ê *(<-ýìíëý 9ýõìýNýRK Pô íëëðêäíç ðìèé 5ëæê 5HVý (5-ê* (<-ýå ëéý9ý õåëíýNý RKPô íëëðê äíçðäåç 5ëæé 5HVý(5-ê *(<-ýìíëý 9ý ...
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E.F. Johnson Company 761X - page 84
PART S LIST 7-19 Nove mber 1998 Part No. 0 01-7600- 001 &çè &H UDPý&ìçíåý&+ ýì+ýéæí-ð7ð$ íë ëðêäíç ðçíí &çç &H UDPý&ìçíåý&+ ýì+ýéæí-ð7ð$ íë ëðêäíç ðçíí &çæ &HU DPý&ìçíåý-%ýì +ýìíë.ð7ð$ íë ëðêäíçðíç í &çä &HU DPý ...
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E.F. Johnson Company 761X - page 85
PARTS LI ST 7-20 November 19 98 Part No. 0 01-7600- 001 5éì 5HVý (5-ê*(<-ýë æéý 9ýõëæ íýNý RKPô íëëðêäíçðìæä 5éë 5HVý (5-ê*(<-ýê êéý 9ýõêê íýNý RKPô íëëðêäíçðìåí 5éê 5HVý(5 -ê*(<-ýì ëêý9ýõìë ýNýRKPô íëëðê äíçðìç é 5éé $UUDý (;%ð9å9ýìí ë-9 íëë ...
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E.F. Johnson Company 761X - page 86
7-21 Novembe r 1998 Part No. 001-76 00-001 MP2 (C) MP3 (C) MP2 (F) DS1 (F) EP2 (F) MP1 (F) FRONT UNIT W3 (F) J1 (F) MP7 (C) MP1 (C) MP7 (C) MP7 (C) MP4 (M) MP1 (M) MP2 (M) MP13 (C) MP7 (C) MP5 (M) MP6 (C) MP7 (C) MP11 (C) MP12 (M) W7 (M) J5 (M) MP6 (C) MP5 (C) MAIN UNIT (Bottom side) MP3 (M) MP7 (C) J1 (C) MP9 (C) SP1 (C) MP8 (C) MP7 (C) MP4 (C) WS ...
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E.F. Johnson Company 761X - page 87
UHF (7640) EXPLODED VIEW 7-22 November 1998 Part No. 001-7 600-001 ← ← ← ← FOLDOUT (VHF Exploded View) ...
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E.F. Johnson Company 761X - page 88
SECTION 8 - SCHEMA TIC DIA GRAMS A ND COMPONENT LA Y OUTS 5V 5V 8 7 6 5 4 3 2 1 BAL REF T4 T3 T2 T1 AF DTCS IC5 SCK SO PLST UNLK 5V x1 or x2 NWC R5 L26.L27 2nd Lo PLL IC REF OSC BAL REF FM DET IC3 NOIS SD FI3.FI4 or FI5 NWC CERAMIC BPF BPF x3 DISC IC2 LOOP FIL VCO 5V 5V C60.C61 Q7.Q8 D7.D8 L14 Q10 Q5 RIPPLE FIL BUFF BUFF BUFF Q4 Q6 5V TX/RX SW D5.D ...
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E.F. Johnson Company 761X - page 89
VHF (7610) T ransistor Basing Diagrams VHF (7610) Diode Basing Diagrams 8-2 November 1998 Part No. 001-7600 -001 ...
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E.F. Johnson Company 761X - page 90
8-3 Novembe r 1998 Part No. 001-76 00-001 VHF (7610) MAIN BO ARD BO TTOM VIEW FOLDOUT → ...
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E.F. Johnson Company 761X - page 91
8-4 November 1998 Part No. 001-7 600-001 VHF (7610) MAIN BO ARD TOP VIEW ...
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E.F. Johnson Company 761X - page 92
8-5 November 199 8 Part No. 001-7600-00 1 VHF (7610) MAIN BO ARD SCHEMA TIC 15.3MHz 3.6V 2.2V RX:1.2V RX:0V RX:0.63V RX:4.7V RX:0V 7.7V TX:0V RX:5.0V TX:5.0V RX:0V 13.2V 5.0V (PMR) LMR (only) 13.2V 5.0V 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 IC2 µPD3140GS VCC1 IN1 ENB CLK DATA T1 LOK CP1 FI1 FO1 GND1 IN2 VCC2 XB XI XO GND2 CP2 FI2 FO2 ...
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E.F. Johnson Company 761X - page 93
8-6 November 1998 Part No. 001-7600-001 FOR REV D1 T8V R8V Q1 Q2 RFATT T1 T2 D3,D4,D5 D7 D8 R8V R8V Q3 Q4 D13 N/W SW N/W SW N/W SW T3 T4 D9 D10 FI1 46.35MHz X1 FI2 FI3 NWC D12 Q5 DET AFOUT IC6C,D Q22 5V 5V B IC4A 8V RMUT TXC IC12 IC11 IC11 Q32 IC9 HV J1 1 2 J2 HG MIC AFO MICIN MICOUT 5V IC8B A MMUT AFATT IC6B IC11 IC11 BEEP IC8A IC7A MOD AFON 24 23 ...
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E.F. Johnson Company 761X - page 94
8-7 Novembe r 1998 Part No. 001-76 00-001 UHF (7640) MAIN BO ARD BO TT OM VIEW FOLDOUT → ...
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E.F. Johnson Company 761X - page 95
8-8 November 1998 Part No. 001-7 600-001 C194 R65 R1 13 R112 Q17 R66 R69 C92 C91 MP1 0 D28 D16 J6 W6 W6 RED BLK C196 R173 C1 95 C84 Q18 Q1 4 IC 3 C81 IO C79 C101 L17 C304 L19 R7 0 C100 C80 C74 IC 2 IC 9 C76 C7 0 Q12 Q13 DET W12 CPU5 C298 R58 C77 R8 T8 TMUT C78 C67 C68 C3 25 C32 6 C327 8V C328 C206 C238 C7 5 C71 J2 C281 5V R206 R205 R204 C232 IC 13 ...
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E.F. Johnson Company 761X - page 96
8-9 November 199 8 Part No. 001-7600-00 1 UHF (7640) MAIN BO ARD SCHEMA TIC 5 6 7 8 9 10 15 14 13 12 OPT2 OPT1 AUX MIC IN SIG OUT OPV1 OPV2 OPV3 BUSY MIC OUT PTT OUT PTT IN 3 2 1 4 11 OPT3 GND 16 J4 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SCK SI SO OPINT OPCS AF OUT DET RXMUT AF ON MIMUT HV 5V GND TO OPTION UT-96 UT-105 NC NC BEEPO W6 DC CABLE EP ...
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E.F. Johnson Company 761X - page 97
8-10 November 1998 Part No. 001-7600-001 P2 P3 P1 P0 V-DN V-UP DN UP DS4 DS3 DS2 DS5 DS7 DS6 DS8 PWR DS9 DS1 DS10 J1 DS1 1 2 R60 1 2 7 8 J1 (To Microphone) 1 - 8V 3 - AFO 5 - MICE 7 - GND 2 - Clone 4 - PTT 5 - MIC 7 - Hanger R51 R52 C1 R61 C16 C73 C11 R53 R5 C18 C19 R7 R8 C13 R63 C21 C79 R64 R62 C14 C20 R6 R43 C17 C3 C2 R2 C67 C65 C66 C80 C62 C61 C ...
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E.F. Johnson Company 761X - page 98
8-11 November 1998 Part No. 001-7600- 001 LIGHT ON :7.5V LIGHT OFF:5.5V 5.0V 5.0V 4.9V 3.9V 1.7V 5.0V 7.6V 5.0V MEASUREMENT CONDITIONS DIGITAL MULTIMETER:50k Ω /VDC OSCILLOSCOPE :20MHz 3.2V 2.3V 1.4V 6.8MHz 4.2V 2.3V 0.4V DTCS 0.7V CTCSS 2.35V 4.0V 0mV -70mV 70mV 27.5mV BEEP IS SET -27.5mV 0mV 3.3V 0.5V 1.9V TX:5.0V RX:0.2V 5.0V 1 2 3 4 5 6 7 8 9 ...
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E.F. Johnson Company 761X - page 99
8-12 November 1998 Part No. 001-7600 -001 2SB1132 R (Symbol: BARB) 2SB1143 S 2SC4081 R (Symbol: BR) 2SC4215 O (Symbol: QO) 2SC4703 SE (Symbol: SE) • TRANSISTORS AND FET'S 2SC5107 O (Symbol: MF) 2SC5110 O (Symbol: MGO) 2SD1664 Q (Symbol: DA) 2SJ144 GR (Symbol: VG) 2SJ377 (Symbol: 4L) 2SK241 R (TX) 2SK272 (Symbol: K) 2SK536 (Symbol: BJ) 2SK880 ...
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