service manual change notice t4 diversity receiver
Contents
1.2.
3. EI Li L107 82A8004 49 9 kQ mi gl 162A12 al oy C Line T C pel 390 oon 047 uF m A101 TPA C8 ETT T499k0 o 20 0 5 pF aa amp por ee n R8 csl Log 20 Tx d C14 035 SE 13 A 1 Q2 CFR 499kQ 047 uF 470 uF c12 c13 cb G2 cios cn Geo nad ACC 32 47 pF T 86A8910 18303 8648910 i 16v EE GI d LI sn dis 150pF GIL 183412 34 ai im L Ceramic R12 we e C16 5348322 1pF ell a 9V Rig LA lc 4 R2 is D C15 Ceramic 825 Q R13 Filter 332 Q 3 LA1235 7 c19 dicc 183A23 4 n zs rs C17 TPA 1 270 pF Fig 100 01 uF gig CW C19 E AA ma 3 20kQ gaz uF e 14 PM Detector ca d Ge o 4i In d 2 620 C21 R173 eau 7022 TE R193 Tcog Tiso d Ri82 ca C23 ATi 13 Muting TPA2 sl t 100O0 001 uF 001 uF Riss 100 of C26 isop 499 Q 047 uF 047 uF 12 A L s l4 1 20kQ cool 1000 L cal TPMO L L 047 uF c27 av 047 uF H SE 047 uF 4 ale L C75 1 18 82A8003 os mi 001 uF T 828003 vers EH Usos 1 182kQ 1 82kQ cael 40 32 dn R172 C37 E Jil 10 pF R 499kQ 01 uE i pos 39 49 9kQ R51 499 Q ud ee 1 05183403
4. G if P Channel A 49 9k mil ol 162A12 all C4 N4 R5 3927 047 T A opt zR6 N7 P N6 dte nm oor 047 E A101 TPA1 C8 N12 499 di 332 N10 5 pl SS 8 L L lee EE i Ni5 C9 N16 DO na N24 s N19 ER G2 y 2D ct 1 82A8003 4 Nt C14 Not Q32 N14 OT N13 I 4 Q2 EFL N17 047 470 uF 1 c12 C13 C77 wg N20 o en Te 3 33 2 47 pF 86A8910 183A03 2 86A8910 I 16V 53A8322 1g hF 1 pF 33 s teel igp g dpa wes 150pF GIU SA 183A12 44 FL3 SRM Zus L L Ceramic pm AB El cig eer urs a NE RM 5 711 Ct7 cte Dieu 12 TH r 1 Ceramic 82 R13 Filter 3327 3 ECH 1 455 nas Sta m n Gu cr au w Ze Teas 20k cos cisci PE miter CS Oigo N28 14 FM Detector cgo mp KS ot 43110104 C20 R17 lt ca 102 R193 To 8 L g Riss ca C23 27115 i TPA2 L IE i pe 100 001 o vt asi 100 10 Tiso pF Ng1 4997 R 047 wae i w i Muting L 1 ewe L 25 20k cool 100 d cl TPA40 N202 047 047 C27 NO gy a 047 Love cmi LD s 828009 T R24 we Ai 42248003 1 82k C36 3 dg C32 037 15 pF et 10 pF 1001 ms NAP Nao 49 9k z 499 N85 Crystal N44 Q5 183A03 040 N45 Y100 R26 20 pF 1 xxMHz 40 8003 24 94 P R282 DTD Te L Ze 601 ov L10 N51 Channel B t w ii cas 1162412 c46 1210
5. g dl aldl Ved Vidl oR SS E Geeks i gm A102 E L DN A A 5 5 ER TA Am 5 Sem En ES m R126 e E y100 D Se Cep Gs C51 EI E EE Bier RST C R9 L6 RI ce Tas C58 SE ee e 978 ka t5 r L5 E77 He m E Si E SS sqm mm Di Ei LM C55 C50 le SH al ei a Q3 Ip at E E SS ER E er N a ig y RS m B 3 E S C28 024 azd L 24 m EN 3 EUA o GC ES RIZ L Vedl j RER SS GER 6dL 37 T UB Lux RAI C65 C86 R43 L 3 R106 5 RI68 a UI e g Es 38 188 ERR c6 8 B up 8 3 GR N 7 q 6 GEI 388 RZ R33 c63 8 i fara ix D GER E si a S EIS Vidi HSE EIS ela E 2 El Gei RE E mm 8 20 m ee dech Ben E RET Saus RE 4 qe Gu eee CIS CS Ss C057 RIS E ei esa BERB E MRE e ES e gbdl mz SE ca Elle ua E E E RES z 1106 5 E LEBU RE C44 Ele enl C49 2 ch L Ce S E EER TASES 1818 SS ita Pe Te e s Bs E Els RIS v CH VSdL TES B i em El HE al ES e mem d Vldl e Ese uy mm G Gees y 5 E H Er pio Se S RGAE B So 159 5 c15 5 due Biz RE gZdL e oa a e ci RTI 8 BS E KE 2 f in 3 E C140 Sieg M csa L103 E E e E B c53 1105 E m 8SdL Lo 89d V9dL 98d NO SI SUUByO OPA 6 JI PL Uld 9OLN gZd L OPA OVO JO pue eAnisod J9dL oipny Z Uld 80LN asd juawuBiy Je EL uld zn ard julod 1S9 Ju gEdL egeo 1ndu 6 0S ged L ejgeo 1ndu y 0S ald gue OPA 6 Uld LOLN Gdl OPA G Uld en 8d
6. C102 N36 sv 38 T Mio TPSA Riot yore 188120 n RC4156M 100K N102 N103 U105C ol ol o Note Net name must be equal at GE Ge each B Channel bias point 8 YX Pin 7 Channel A 5 2 Pin 2 of R16 9i 9v N34 N106 R104 N107 D10 pM Wun mer Weg B Channel bias 00k 20mV Ref 150pF n111 R108 Imm 1M RUN 4 Move 150 pF 20k uosa SU N115 CIOB N118 num Ge 2 BR Rt Juan Wy R112 Nios close topin8 N116 i th Ji 100K of NES71 33pE 499 10M 3 8 R114 N123 5V tz ennen 290 ens w it 3 H84A08 Ciel 10M N121 A Tas LP839MX P BEEN Mute Drive R119 330pF U107 C gt RC4156M p 200K 100K 20mV Ref C114 Voli 475K 124 LOSA 9v N125 LN mt vu yrogd gt TI UNE we CUM N133 1 u105 D gt gt 14 We oss pov AN WG 270 196004 50V elen 99 i 10uF x 35V an J3 C118 was R125 J101 vi Kc Ni34 221 P339MX cng 9V R126 T2127 1884120 F 001 L 001 M use 0120 BER A R 4 ov sia 0039 8 ue cw 1 RC4156M MES TP7A R131 182 N137 e U106A 4 9v Di EN N139 J L101 R135 A 88A04 24 9k 16 5K R134 N140 CY 162A03 100K P 12 une Dag R136 Ni41 Ji 1 0K T gv ban d D10 oic R138 188A04 H Nam C123 Lt 9 7 188A04 1M 7 ike N144 41 LP339MX 21 5V C124 1N143 Si Ps 0125 f Tutos N146 Ci26 001 U102C oV 4 T U106C 4 188A120 t LP339MX sou ee 7 0 Yellow lel 5l 18 z 13 8 C161 3 U107B nae 12 1 ER Sek 10 188804 a Ni4S 1 N147 0197 R142 TA 15 par Die 0017
7. Replacement Parts and Drawings 24 Grp C55 C60 C61 C64 C65 C77 C78 A 12pF 15pF 1 pF 0 1 12 pF Not used 3 3 pF 0 1 B 12pF 15pF Not used 10 pF 1 pF 0 1 3 3 pF 0 1 C 10pF 12pF 1 8 pF 0 1 10 pF NA 1 8 pF 0 1 D 10pF 12pF 1 pF 40 1 8 2 pF 0 25 1 pF 0 1 1 8 pF 0 1 E 20pF 12pF Not used 8 2 pF 0 25 1 pF 40 1 1 pF 30 1 F 20pF 10pF 1 pF 0 1 8 2 pF 0 25 Not used 1 pF 0 1 G 20pF 10pF NA 6 8 pF 0 25 Not used 1 pF 0 1 H 18pF 8 2pF 0 25 1 pF 0 1 6 8 pF 0 25 Not used 1 pF 0 1 J 18pF 18pF Not used 15 pF 1 8 pF 0 1 3 3 pF 0 1 K 15pF 15pF 1 8 pF 40 1 15 pF 1 pF 0 1 3 3 pF 0 1 L 12pF 15pF Not used 12 pF 1 8 pF 0 1 3 3 pF 0 1 Frequency Dependent Parts IV L3 L4 L6 Grp L5 L14 L12 L13 L15 R24 R26 A 82A8003 82A8003 1 82 kQ 24 9 kQ B 82A8003 82A8003 1 82kQ 24 9kQ C 82A8003 82A8003 1 82kQ 24 9kQ D 82A8003 82A8003 1 82kQ 24 9kQ E 82C8003 82A8003 1 82kQ 24 9kQ F 82C8003 82A8003 1 82kQ 24 9kQ G 82C8003 82A8003 1 82kQ 24 9kQ H 82C8003 82A8003 1 82kQ 249kQ J 82C8003 82C8003 1kQ 12 1 KQ K 82C8003 82C8003 1 kO 12 1 KQ L 82C8003 82C8003 1 kO 12 1 KQ 25C1020 EA Shure T4 Diversity Receiver
8. IVdLZVdL 4GZOQV YE LT 5 m 010 E om 5 son Zeg 519 e ENE B5 m 2 e los SS vaa 2018 NES 6 8 2019 El LS LAS eo 22 ERI SE AE ais E 6 GC Eis els s BE qe E ae Im 3 E S B ez EN El E 060 E FL r1 IN ICH ES es S 8 S ES E an 28 Ej 5 Ce 8210 0j s us HA Hu D E z 83 E 5 er nia TI 5 log ke cones E CH LZ S 5 E Els FA Kiss E 2 T S G E m B e Si S eu El a EE a a se Es e e Yr d ERE 0619 vig ED T1 zon dE A um e E S zu SCH 5 5 VIN 3 te a BRE Eta al a d HBE e m 0c m s Gd 0 Set 5 Ermm son 4 H s STE z gt El i 2 2 st ENE cl m 5 1 ro 8 cud y fu oa 030 E el a coir ap 3 93 ei D z e oua CC 699 y El 3 als E d 5 B II a 3 2 a g E 7E m E Eom 192 E TIERE e a E 5g 900 s 8 859 rr n ES on I 2 LE SC 5 E 2 3 Gs 3 a Elle ZEN s EJ 3 GIS 5 Ed ERE LE Z O Em E 1 5 A E suo 58 Z Bg Cat Ex rer El SS ll 8519 5618 1618 a G e t Es AO BE E S sw 4g iat EP A rp i 3 S El aisen real zor ioir SR EIS 2 Zon 5 be d 6010 E yon LR x E e m a E Ca sia E ua er EIE ela E ji le Ge eg a 3 SIS fa O aw c5 ws em 5 Figure 5 74 Heceiver Pc Board Component Side 25C1020 EA 25 Replacement Parts and Drawings Iver ty Rece IVer si Shure TA D
9. SJUIO y 1591 dL NO S 8UUByO OPA 6 JI EL Uld 90LN vidl OPA L LLLO Jo pue SANISOH VIAL oipny 8 uld GOLN v dl yu wu ily Je L Uld LU Wed jutod Sat 4H VEdL egeo indu G 0S VZdL ejqeo indu 6 0S Ytd L vm Earlier Version of T4 Receiver Pc Board Side 1 Figure 6 25C1020 EA 26 Replacement Parts and Drawings 19 Li
10. B LED should be off whether or not an RF input 16 25C1020 EA Audio 25C1020 EA Shure T4 Diversity Receiver signal is present If you obtain different results compare the dc voltages at U106 U107 earlier units only U103 and U105 U108 with those of a prop erly working unit or replace the pc board If the muting circuit works but has insufficient adjustment range set the RF generator for a 95 dBm signal and check TPA4 TPB4 for 1 2 Vdc as de scribed in the preceding Tuning subsection If you get a lower reading consider the following e Low RF levels at the input of U1 U2 will cause inadequate noise at the output of U105D U108A e n order for the noise squelch circuit to function the detector portion of U1 U2 must also be functioning properly see the following Audio subsection f necessary check the component values and dc voltages versus those of a known working unit of the following Noise amplifier U105A U108C High pass filter U105D 108A If there is no audio at the output of the receiver e To verify that the receiver is not squelched defeat the squelch circuit by rotating R16 R41 fully CCW There should be 9 Vdc at TPA7 TPB7 and the yellow A B Diversity LED should be on e fthe preceding test does not yield the proper results check for a prob lem in the squelch circuitry see the Muting subsection immediately above Next check pin
11. Table 3 Frequency Dependent Parts Grp Desig C8 C51 C10 C11 C12 C56 C17 C18 A R210 Not used 1 pF 0 1 12pF 18pF 15 pF Not used B R211 1pF 0 1 Notused 12pF 15pF 12pF 1 8 pF 0 1 C R212 Not used 1 pF 0 1 10pF 15pF 12pF 1pF 0 1 D R213 1 8pF 40 1 NA 10pF 12pF 12pF Not used E R214 1pF 0 1 1pF 0 1 20pF 12pF 10pF 1 pF 40 1 F R215 Not used Not used 20pF 12pF 10 pF Not used G R216 Not used Not used 18pF 10pF 10pF Notused H R217 1pF X01 1 8pF 0 1 15pF 8 2pF 2 p 1 pF 0 1 J R218 1pF 0 1 1 8pF 0 1 15pF 18pF 15pF 1 8 pF 40 1 K R219 Notused 1 pF 40 1 15pF 18pF 15pF 1 8 pF 0 1 L R220 1pF 01 1 8pF 0 1 12pF 15pF 15pF Not used Frequency Dependent Parts II Grp C19 C63 C20 C21 C33 C36 C40 C42 C54 A 56pF 12 pF NA 15 pF 20pF 20pF 1 pF 40 1 B 56 pF 10 pF 1pF 0 1 15pF 20pF 20pF NA C 56pF 10 pF NA 12 pF 20pF 20pF 1 pF 40 1 D 56pF 8 2 pF 40 25 1pF 0 1 12pF 20pF 20pF NA E 56pF 8 2 pF 40 25 1pF 40 1 10pF 20pF 20pF 1 pF 40 1 F 56 pF 8 2 pF 0 25 NA 10 pF 20pF 20pF NA G 47pF 6 8 pF 0 25 NA 8 2 pF 0 25 20pF 20pF NA H 47 pF 5 6 pF 40 25 1pF 0 1 10pF 20pF 20pF NA J 56pF 15 pF 1pF 0 1 6 8 pF 0 25 10pF 10pF NA K 56 pF 15 pF NA 6 8 pF 40 25 10pF 10pF 1pF 0 1 L 56pF 12 pF 1 8 pF 40 1 5 6 pF 0 25 10pF 27pF 1pF 40 1 25C1020 EA 23 Replacement Parts and Drawings Shure T4 Diversity Receiver Frequency Dependent Parts III
12. 18949 L Output i ower 12 18Vdc D10 TP9 Frequency dependent parts see Table 7 near the end of 100k0 T 8 C149 V C517 J103 L103 D108 9v the manual Ries U109B q 49 10 uF 35V 120 pF ot 0 ji C156 a 10 uF L104 Ries 3 H a e mE x 1 D109 14 ne 3 7 R170 R174 and R175 are only used with the Harris FM Detector i 10 k R167 35V 162A12 7 L UA7809C l pu Ou Be Gd C153tL 8688944 Los 1K N S not stuffed Leave off R134 R136 C123 C126 10kQ B 10 uF 100uF Green g A L105 D C155 35V Loga 16V 5 U104A On first production 162412 i B E 95A8519 C el la IC Es E db R17 R45 49 9 Q A R7 R36 33 2 Q C40 10 pF from 90 8550F 11 Ceramic Discriminator 9v L1 Ni DOT N27 H N2 P9 1 Channel A R1 162403 wl R2L 1 86A8920 49 9K Gla Es 875 R3 370 Sle 8 287 2p N4 392 379 R4 N3 c4 Lg re R
13. L9 Inductor SMD 1008 22uH 220nH 162C06 L107 108 Quadrature Coil 10 7MHz 82A8004 Q1 6 MOSFET metal oxide semiconductor field 183A23 effect transistor SOT 143 35K131 Q2 4 5 7 Transistor UHF VHF RF SOT 23 NPN 183A03 MMBTH10L Q3 8 Amplifier 2 Gate Hi Gain Lo Noise SOT143 183A12 3SK177 R16 41 106 Potentiometer Linear Taper 5 kQ 46C84 168 R112 Potentiometer Linear Taper 100 KQ 46A8008 Squelch R126 Potentiometer Log Taper 10 KQ Volume 46A8046 U1 U2 Integrated Circuit FM IF SO 16 LA1235 86A8877 U3 Compandor SOL 16 SA571D 188A01 U101 9 V Regulator MC7809CT 86A8944 U102 106 Comparator Quad Low Power SO 14 188A123 LP339M U103 Switch Multiplexer Quad SO 14 188A19 HEF14066 U104 LED Bar Green Yellow Yellow Red 95A8519 U105 108 109 Quad Op Amp SO 14 MC33179D 188A49 Y100 Crystal 40 8003A In the underlined space insert the appropriate Crystal Code from Tables 2 and 3 p 10 Note The tables on the following pages list frequency dependent parts Replacement Parts and Drawings 22 25C1020 EA Shure T4 Diversity Receiver In the following four part table Grp is the board s frequency group and Desig is the number of the resistor that designates the Group Number The parts are listed across the tables in alphanumeric order All capacitor tolerances are in picofarads
14. N193 Mu 5K EM zu 162A03 dd C153 86A8944 UA7809c 4 C152 1 0K First production assembled with d N197 10K R168 I dag 199 N198 R17 R45 49 9 ohms and 1 Soe N196 Ri Si y uU Green o R7 R36 33 2 ohms RC4156M 162403 Y C155 ple V o Utoaa C40 10 pF I d 001 SS E 9 4999 Shure Brothers Inc 27C1020 SB T4 Earlier Version Schematic page 2 of 2
15. the test points controls and tuning components 2 Tack solder the cable to the pc board as follows Channel A Center conductor to the antenna input TPA1 and shield to ground TPA2 Channel B Center conductor to the antenna input TPB1 and shield to ground TPB2 11 Service Procedures Shure T4 Diversity Receiver Display Check Presettings Most field units should already be tuned closer to the desired settings than these approximations However you may need to preset units when you are changing the frequency or an RF coil or when an unskilled person has attempted to retune them Minimum inductance occurs when the core is level with the top of the can Turning the core further counterclockwise or even removing it will not appreciably affect the inductance Maximum inductance occurs when the core is about two turns less than its full clockwise rotation about 3 2 mm is in below the top of the can Never screw the core against the board The manufacturer s setting of the two smaller IF coils L2 and L11 is close to their ideal setting so you generally would not preset them For coils L3 L8 and L12 L15 refer to Table 2 or 3 page 10 to determine where the desired fre quency lies within the board s group For frequencies near the bottom of a group use the maximum inductance settings for frequencies near the top of the group use the minimum inductance settings 1 Connect an external 12 15 Vdc supply to
16. F S D N123 5 us SC 137 4 200k ov N125 20 mV ref 15k C163 ZC Va En RE 7 N28 R120 wa 40114 Ni2 Volume 14 188A04 1 10 4F 35V 3 EE U105D R122 1 10 210 E 499 LF C118 R125 SW A 88A49 W i 2 21k C158 Cu R123 R171 LP339MX 50V oV R12622 N132 MES J101 min 001 eeh 9 paag tid 47 HE EN oyl 332 3 N134 N1354 X13 E R1303 001 1 L U106A gt UD M obj 100k iQV NI J tor T f2 R139 aS 162A12 188A04 tk L LP339MX N201 CLS Yellow 5V U104B 4 9 V106 13 haos yenes d vue C126 9v e n N145 Hooks r Y 5 Ca Heer BH k be uweer AM pi Ae R143 01 LIT s DEG rA 1 F p Wan 2 18801 j 4k Pin 7 U2 Channel B lge gt me em Es AM SE Corpandor A See ZS i D T 4 4 Red pin 2 of R41 Ts 100 pF AIME A 9 49 9 047 P 158 TS a 95A8519 4N80 Ni R148 we RER t 9 N154 Ll e 2 R147 Ni57 L cl E A mal gi zu L we vod et Ein me A a A C134 Wer om N168 5 cun gt 8n AA08 1 3 sv T y TP8 1 db 33 pF ca EI LP339MX f Mp 390 PF Gag R151 R152 170 C138 Je 01 N164 R1542 330 pF N173 A Yellow js Channel B TOR C140 NUS ma out sue l 1 12 p 188A49 i 5V 50V g N200 E A Pin 6 of U2 ug Ut03B d ERSO eny gn U108D 4 A 188A19 tk sov PL A 18 1619 z as 184A08 gj Ro Geer Ge n179 C145 N178 gt N180 R159 TPB5 Jg four 750 a7 UF y N93 n 5r 188A49 A Ow u 102 71106 16212 i Wei 7 ECN 5V 100K e E 35V W I egy CM6L 162 t2 va R162 D1 t z N176 E 100V Zon J102 6 81k 1 R164 miel caL Output N
17. L R143 ut T 12 d asaos Uroap 01 T 7 LP339Mx 2 Du Bc oxsov 0 Wa JL E wan Jump ve X Ed 5 Lol LP339MX U106B Uea gpm 129 N155 3 Compandor IC i 188A04 U102B N153 188A19 E 2 4 TuF x 35V 4 nTe 10 R146 pas QRT rel iy Red Pin 7 U2 Channel B 6 188A04 N158 N157 49 9K i y U104D Pin 2 of R41 R148 or LP339MX E EEN ER 8 1 Ngo N160 N161 2 a ciae R147 L C136 D 141 1 0 150pF R149 100K pioz F niee U 06D T 50V Nig 188A04 95A8519 3 n we N165 gok U108C ES Mer C135 me ve L P s cnr e wen x sv TP8 po o 5v 188A120 330PF C139 S9PF Rist R152 oa N171 o EA n164 1 1 T M 4156M pur 330pF aX 200K 499 1 igaaos R155 40140 E Yellow Ya toic 10 E Ke M73 yiog ze N1473 49 9K 50V Dig 5 9548519 er N83 5V 4 E RC4156M R156 ow N200 C141 ibian C162 3 la 188A120 49 9K ZN Len R150 10 x om C143 g 2 1 0K sov Flat 4 0144 N77 we 33 we 2d 5 184A08 Ut098 4 2 RIS7 wg 0145 N180 Cros 1884120 poe St R158 Nng x63V OA 5V R159 5 RC4156M TP5B L C160 iOuFK35V 750 47uF x L102 C 162A03 001 12 162A03 s 5V 100K 11 R160 C146 Nido 100K U1088 gt t RC4156M N176 68 1 La a Ries 11 Ll oa T 2 3 1 z om L IR R163 Dio R164 Ni84 op 1884120 100v J102 WE POWER 12 18VDC TP9 C149 R165 C150 N189 Output iouF Ti 3103 L103 162A03 ev o 100K Rigg U109B t F 35V 220pF yn A86 N187 D109 N188 o 4 C156 S 1OUFX3SV 780 47UF x68V S Men N194 2 XQ if dl 1 Tt Bo Leave off R134 R136 C123 1 10K R167 N195
18. Note Shure recommends that all service procedures be performed 1999 Shure Inc by a factory authorized service center or that the product be returned directly Printed in U S A to Shure Brothers Inc 25C1020 EA 1 Characteristics Shure T4 Diversity Receiver Circuit Description RF Stages The Shure Model T4 is a single conversion superheterodyne diversity FM receiver operating in the 169 238 MHz band It is intended for use with the matching Shure T Series wireless transmitters Two complete independent RF sections provide diversity reception Signals enter via the single element quarter wave antennas Channel A The signals pass through a double tuned filter L3 and L4 be fore entering MOSFET amplifier Q1 The output of this stage is double tuned by L5 and L6 which also provide impedance matching to Gate 2 of GaAs MESFET gallium arsenide metal semiconductor field effect transistor mixer Q3 Gate 1 receives the local oscillator signal from transistor Q5 A third overtone quartz crystal in the 50 70 MHz range provides frequency control The collector circuit of the oscillator is tuned by L8 to the third harmonic of the crystal 160 230 MHz to provide the proper injection frequency for a 10 7 MHz intermediate frequency IF Channel B This channel is identical in design to channel A The signals from the antenna pass through a double tuned filter L12 and L13 before enter ing MOSFET amplifier Q6 The output of this
19. Quad Coil i 24 9kQ L108 827 um S fe 828004 1 82 kQ XxMHz 40 8003 R283 c43 AE L 4990 001 uF L10 Cte Gut AV SC i l id Ch L9 16212 J D annel B 33 pF 220 nH C45 C46 49 9 KQ 047 uF 047 uF Carl RAL wi n oro AW T Si uF TPB1 T i S o Pu C50 2 1 82 kQ DOT 1 U2 t dev A102 c51 AP i DOT 1 e oF gs R39 86A8877 5 C53 fo cse 057 cre GAT oe ren 4955 dee c58 I3 188A03 2 Ceramic 3320 4 LA1235 ON HA 81 Sis Fall a 150 pF q He SR 2 l Filter FM Detector Lo HF Raid 53A8322 1pF ZU A Li C60 x C59 Ceramic 825 Q R42 86A8910 Get 5kQ Muting 1 ce3 PE 183 3 _ a R43 oxi Li5 C61 270pF Filter 100 C627 24 15 12 13 6 M6 150 pl 304 C03 I 9V100 0 m 86A8910 047 ui TPB4 TPB2 0 4 id TE4 Teea TO Rass L ceg T6606 Hs R46 C69 crt al nia 2 Ey 4 10027 001 uF 001 uF 9v 499 Q 047 uF 047 uF C67 4 99 kQ Tri us m R49 4 SS SCH 14 047 uF Lil Ly 1 En 100 2 SS em Audio 4 18849 9v 001 yl Pin 6 of U1 sh 7 14 E 4 1058 10 C102 d 12 U103D sv T O33 uF 6 L di 188A19 R101 tor 188A49 TPAS 188A19 L 7 100 k2 8 9 U105C 8l I R103 Pin 7 Channel A Ke ep Pin 2 of R16 eus y p D101 9v 4 R104 35V R105 COT prgg y 200K2 me L ITH tas B Channel Bias e kO 90 mV ret 150 pF 5 1 C107 C108 R109 Ct d 2 gil D R112 gy U105A i e ek i remm 2 3 100 ko R114 acens OPF DO Rus 499 0 1 ur 184408 y A n Sa CIEL 1 oie ER KO 188449 Mute Drive R1193 C113 49 9 kQ
20. by shutting off compandor U3 The audio signals from the two channels pass through analog switches U103C and U103D are buffered by U109A and enter U3 which provides a 2 1 logarithmic expansion An additional IC amplifier U109D operates in conjunction with U3 to provide a lower noise floor The output of this stage passes through the Volume control R126 to the Output connector J101 A bridging amplifier formed by U109B and U109C provides the Balanced Low Z output This red indicator warns the user when the transmitter deviation is approach ing the limit of 15 kHz This function is implemented by a window comparator U102C and U102D and a pulse stretcher U102B that makes short transients more visually apparent The green Power LED indicates when the external power converter or a battery pack is supplying power to the receiver The circuitry operates normally with an input of 12 18 Vdc D10 provides reverse polarity protection and U101 supplies voltage regulation The Dc Input audio Output and Balanced Low Z output connectors are filtered to prevent local oscillator radiation from the cables 3 Characteristics Shure T4 Diversity Receiver Notes Notes 4 25C 1020 EA Shure T4 Diversity Receiver Preliminary Tests Listening Tests Before disassembling the unit operate it to determine whether it is function ing normally First and most important Review the customer s complaint if avail abl
21. preset position and adjust coil L11 Adjust coils L11 L7 L12 L14 L13 and L15 in that order for maximum voltage at TPB4 Use a hex tuning wrench for all adjustments except L11 which requires a non metallic screwdriver like a Toray driver Reduce the generator output as required to keep the signal voltage under 3 Vdc Perform the final adjustments with a generator output of approximately 85 dBm Note For coils other than L11 the sharpness of the tuning depends on the operating frequency within the frequency group At the upper and lower edges of a group a distinct peak may be difficult to observe In this case adjust the core for maximum indication D Channel B Audio Note Before making the following adjustments power up the circuit board for at least one minute This allows the FM detector to stabilize 1 Set the signal generator for an output level of 60 dBm a modulation of 1 kHz and a deviation of 15 kHz 2 Version E and later boards only With the probe of an ac voltmeter on TPB5 pin 7 of U108 adjust L108 for peak output Adjust R168 for 0 dBu 775 mV 0 1 dB at TPB5 4 Reset the signal generator to its minimum output level or Off Check that both Diversity LEDs turn off Level 50 dBm Ext Modulation 50 kHz Deviation 15 kHz 5 Setthe RF signal generator as follows Adjust R41 for 1 Vdc 0 5 Vdc at TPB6 the positive end of C140 6 Turn off the modulation of the signal generat
22. yellow LD Power green Antenna A Service Procedures Shure T4 Diversity Receiver Coil Adjustments Service Procedures Each channel has to be adjusted separately Channel A RF and IF 1 Disconnect the power to the receiver Mute Channel B by grounding TPB7 pin 14 of U106 Reconnect the power Adjust the signal generator s RF output so that you obtain a reading of approximately 2 Vdc at TPA4 If this is unattainable even with the full 20 dBm generator output adjust IF coil L8 until you obtain a reading above 2 V If you cannot get more than 1 25 V return L8 to its preset position and adjust coil L2 Adjust coils L2 L8 L3 L5 L4 and L6 in that order for maximum volt age at TPA4 Use a hex tuning wrench for all adjustments except L2 which requires a non metallic screwdriver like a Toray driver Reduce the generator output as required to keep the signal voltage under 3 Vdc Perform the final adjustments with a generator output of approximately 85 dBm Note For coils other than L2 the sharpness of the tuning depends on the operating frequency within the frequency group At the upper and lower edges of a group a distinct peak may be difficult to observe In this case adjust the core for maximum indication Channel A Audio Note Before making the following adjustments power up the circuit board for at least one minute This allows the FM detector to stabilize Set the RF signal gener
23. 185 e z Power 12 18Vdc D10 Niga 1018849 Se A Cibi 0148 J103 L103 Dios gv E Leave off R134 R136 C123 100k migg Ut098 9 08193 IR 3 we N189 10H 35V wa 120 pF od N186 N187 N188 0 4 i s C156 7 2 gut 750 N191 47 uF L104 iea E wer gt ie o H 3 HIS On first production e tok 97i 35V 63V 162A12 5k Ft ou D I Cugat H Er Minos R17 R45 49 90 w oq W a ue AT K ID ye DL osnesio EE A O A e o EE T4 Schematic 001 l E R174 and R175 are only used with the Harris FM Detector from 90 8550E 11 Channel A
24. 50V U102A 150p n bid 13 4200 kQ ay M 20 mV t A 1 5kQ 150pF Lone leas R120 gia valime o uod 49 9 KQ C158 49V 10 GE RIT BE IM et 499 0 04 CE C118 R125 J101 PEA 188A49 Wil Loi uF 100 M i sul 100 0039 uF R128 CST E ae KOR 4 47 uF 63V 01911332 kQ 2 3 S13 Wis R1303 001 uF 1 9V 1MQ H 2L Jm 2 TPAT V 100 kc2 1001 L101 o R139 162A12 188A04 DO 1kQ R138 LP339MX 4 el MQ 9v Hs 13 mb Im NN Utozc 4 UE 1844081 Y 95A8519 C126 NS Sp La a 28904 19V 1 E SE LP339MX 188AQ4 C161 C128 LP339MX 145 Y Rioko Ut09A gt ak 3 188A01 8 13 PLENAS orak F i00ko gt atasa siv ert NEST wll 10k 2 SE vg me GT Lem Ve a T n imus Dx Dat t a Red AB8A04 T 4 7 uF 35V 5 e pin 2 of R41 LP339MX IER r 49 9 kQ E re UIDAD 95A8519 4 R148 yg 01251 1 gt Beem Ciao R147 E zn C136 ggg y 200K2 5 Op vied 4 2 piza TF 301kQ J 150 pF a Cm eius UL 18804 184 08 1 3 sov I sy TP8 20 kQ V up i T 8 C137 LP339MX f E 10 DET Z cios R152 C138 js lut f p 200kO 4992 04 uF Yellow 5V H C140 NA A Channel B 4 75 KQ iu pn uie 95A8519 ov 188A49 i 7 3 1 EE 14 Pin 6 of U2 i qf 188A49 U103B 9 t2 Am CH C162 oot uF U108D gt 14 188A19 1kQ sv PL 137 4 0143 V z 184408 14 C144 R157 18 au 33 9 4r 5g 9v R158 U109C E er i R159 o 188A49 TPB5 C160 tae fi mut 7509 L102 106 162A12 t 79 001 uF 5V 100 kQ 35V L 162A12 100kO U1088 H 188A49 rai D1 t H Ee HUE 68 ka 1 P V R164 10
25. 6 of U1 U2 for an audio signal of approximately 15 dBV If there is no detected audio e Check C1 C44 and the components connected to pins 7 10 of U1 U2 e On earlier units only Make sure that FL1 FL4 is an 86A8920 ceramic discriminator and not an 86A8910 ceramic filter which is similar in ap pearance e Check the dc voltages at U1 U2 against those of a known working unit If no other problem is found replace the IC e f audio is present at pin 6 of U1 U2 but not at the output of the receiver trace the signal through signal amplifier U105C TPA5 U108B TPB5 and expander U3 U109D When measuring at audio TPA5 TPB5 use a 1 kQ resistor in series at the test pointto prevent loading the amplifier e Check the Volume control R126 and the components going to the au dio output jack J101 e On vocal models check for a signal at the Low Z microphone level out put J102 If no signal is present check U109B U109C and associated components e Check the dc voltages on any stage that is not working properly then look for wrong or missing components Replace the ICs in the faulty stage if no other problem is found 17 Bench Checks Shure T4 Diversity Receiver Bench Checks f you cannot set the audio level properly with R106 R168 make sure that the other diversity channel is squelched only one channel should be acti vated during this adjustment If you can set the audio levels properly for each
26. 7 ng ns Ns rss C5 C6 Antenna ES e dia NT 499 no DI NIE C9 IZ 3 D N8 ES R8 047T Tune N12 Qiip T RETEA TP3A N14 R9 Ni5 Y N16 por Nis L a2 36A8910 n 8 9 10 221K oun tev TP1A N19 N87 G2 2 C10 ctt 1 594 0 5pF L d 332 DES 11 3 86A8910 183A03 5 FL2 N17 1 im NT c12 c13 C77 S BW fau N21 3 EJ RH 2 26 7k id Lg E77 Neo 3SK131 V12 G1 1 8pF LN f Jr 7 N23 QM NA sos al L2 d Jana Rm ee L ceramic Fiter nu rech 15 Mes A101 18pF 1pF 3 3pF Tan Sus Rid EN L C17 C18 150pF i a T 270pF Ceramic Filter R13 332 LA1235 ji N25 N24 cig AH a Gel 82AB003 82A8003 15pF RIS NS d Y 10 N28 3 FM Detector IC c30 0 1621 CW 56pF 3 if T 3 l C20l ca AS av 100 Gop L cS 7 5K we ai oca Ges 150pF 5K Ken 35 0154 12pF RITZ T 601 Tom gt R193 C26 va z 409 T 047 0477 12 13 e 16 Muting TP2A SE J L 499 047 S TAA Je 7 nes v L z m cool pog 9Y a ES 82A8003 82A8003 7 047 100 i c27 R22 047 ov AH 37 4K JL lev co gt T om 18 e 7 N38 R23 R24 N39 001 482A8003 8248003 infla C38 L C84 ag 382 css cael au oi d 14 15pF 1 C37 15pFT 1 T 1pF pa AU Be Bre N86 001 mo N40 N41 1 0K E R25 iu N43 o 1 499 PS c39 N85 1pF 183403 3 Q5 N46 183A03 2 R273 041 vio do 424k 1 0K Tom C43 XxMPZ Crystal 001 40 8003 m EL AE l9 Ceramic Discriminator I 220nH dag EIN 1 9v T 8 86A8920 FL4 N50 Channel B i 378 378 j C471 c48 R33 N51 N52 R32 047 470uF Antenna N57 N56 C E D 1 C51 M
27. 910 R210 N212 al 220 nH 047 047 El x R44 R34 B33 ap C47 C48 p 211 Nott R211 N213 N203 T 20k 1 82k wee 047 d n ATI A102 mei C51 N56 C50 we TPB304 9 N54 DOT 1 e C RAI N73 N61 DAET PULETE Nos R38 N64 C52 N65 DOT Ng 1 a7 I M R39 15 A 10K S G f Gel Lir 0 5 pR t194 47 pF ig 183A03 ic 332 SECH 7 C53 ve D pels 1 1 C56 ONU m88 Nes e Q6 Cor AA 300 fg Q8 i p Co ng na Ceramic 3 LA1235 t J OW To sde wat v r sage askai Aas t wesch ESN STE n e S Ceramic 7825 pag Y dl N72 FM Detector 7073 7 R4t Whiting Ge Los 4112 113 183423 lg R43 82A8003182A8003 S PF Low 10 0625 24 15 12 T e He 150pF Sk Eo Natt 1216 56 pF 3 1 E IC64 1 C65 pgs bet 9V 100 Ge cies ii 86A8910 m N79 047 N77 TPB4 e RT p 215 MSL Bets N217 47 Tl2p T S Get H SE SCH cia zu ET 1007 Ton 601 v 150 pFNB2 9v 4997 M aT cor M e ZC R19 0 JL Gaam L is ES l Fg ce d L CA SEH Seel i R217 S BV L E E rfi Audio H o 188M9 9v D Pk SR o 7 U103A 1218 No1g R218 N36 U105B gt Tm ms s J V E N101 Ve ES Do Ae AC W A Riot 49 188449 TPAS wo 188A19 l ZC 100k N102 N103 22 1220 we mm Es Pin 7 Channel A 3V we rg Pin 2 of R16 4i 9v D101 INS wollt N107 Nio CA T y y R105 CHO iy R108 9 200K ale vi bu Rigg BOhamelBlas wg Soe me Ta A uil DI ms Om wspm W N114 pu Mza CW ms Nis Wie UI oan Si cra Blus 499 N12 top 84A08 10M 10M Nias ep EN cn2l JN dads Mute Drive R11
28. Screw 30C1245A Antenna Mount Bracket 53A8322 Antenna Screw 30C1208A Hardware Kit 90VY1371 MP1 Case top 65B8198 MP2 Case bottom 65A8199 MP3 Knob for Volume control 65B8235 MP4 Screw Hi Lo Pan for case 30C1245A MP5 Nameplate Polycarbonate Rear Euro 39A8368 MP6 Nameplate Polycarbonate Rear Domestic 39B8368 Table 2 T4 PCB Replacement Parts Reference Designation Description Shure Part No C6 48 Capacitor Electrolytic 470uF 16V 20 865629 C105 114 144 Capacitor Electrolytic SMD 10uF 35V 151BF106MC 149 151 153 20 C111 116 127 Capacitor Electrolytic SMD 1 0uF 50V 151BG105KB 132 140 141 10 156 C118 145 150 Capacitor Electrolytic 47uF 63V 20 86BE629 C129 Capacitor Electrolytic SMD 4 7uF 35V 151BF475MB 20 C152 Capacitor Electrolytic SMD 100uF 16V 151BD107MD 20 25C1020 EA 21 Replacement Parts and Drawings Shure T4 Diversity Receiver D101 107 110 Diode Signal Switching SOT 23 100VDC 184A08 111 112 113 MMBD7000L D108 109 Rectifier Silicon 140VDC 184A20 FL2 3 5 6 Ceramic Filter 10 7MHz 86A8910 J101 Phone Jack Stereo Right Angle 1 4 inch 95A8329 J102 XLR connector Vocal units only 95A8400 J103 DC Power Jack 95A8328 L1 10 101 102 Ferrite Bead SMD 805 600 OHM 162A12 103 104 105 106 L2 L11 If Coil 4 7uH 82A8005 L7 8 Tunable 10 mm RF Coil Red 45nH 82A8003
29. Shure Incorporated 222 Hartrey Avenue Evanston IL 60202 3696 U S A T Wireless System A SERVICE MANUAL CHANGE NOTICE T4 DIVERSITY RECEIVER Changes and corrections have been made to the Service Manual for the T4 Receiver To update your Service Manual remove the pages identified in the tables below and replace them with the pages attached to this Change Notice Note that there are no changes to pages not specifically identified in the tables below T4 RECEIVER SERVICE MANUAL REVISION HISTORY Revision 1 25B1020 Pink Revision 2 25C1020 White Revision 3 25C1020 White 2507000 mon 8 amp RM CHANGES EFFECTIVE JANUARY 13 2005 REMOVE INSERT these pages from the these new Revision pages into the T4 Service Manual T4 Service Manual 21 amp 22 21 amp 22 1999 Shure Incorporated Printed in U S A 25 1020 1 EA SHURE 25C1020 EA T4 Diversity Receiver Characteristics General This manual tells how to service and align the Shure T4 Diversity Receiver Figure 1 This single channel crystal controlled unit operates within the 169 MHz to 238 MHz VHF FM band Figure 1 Controls and Connectors 1 DC Input jack 6 Audio Peak LED 2 Squelch control 7 Volume control 3 Antennas 8 Audio Output 1 4 phone 4 Power LED jack 5 Diversity LEDs 9 Balanced Low Z audio out put XLR Service
30. ator for an output level of 60 dBm a modulation of 1 kHz and a deviation of 15 kHz Version E and later boards only With the probe of an ac voltmeter on TPAS pin 8 of U105 adjust L107 for peak output Adjust R106 for O dBu 775 mV 0 1 dB at TPA5 pin 8 of U105 Reset the signal generator to its minimum output level or Off Check that both Diversity LEDs turn off Set the signal generator as follows Level 50 dBm Ext Modulation 50 kHz Deviation 15 kHz Adjust R16 for 1 Vdc 0 5 Vdc at TPA6 the positive end of C111 Turn off the modulation of the signal generator Set its output to the mini mum level then gradually increase the level until the Diversity A LED turns on This should occur with an RF input between 102 dBm and 87 dBm typically 95 dBm Disconnect power from the receiver Remove the jumper from TPB7 and the RF input from TPA1 and TPA2 C Channel B RF and IF 1 Make sure that the RF generator is connected to the antenna input for Channel B Mute Channel A by grounding TPA7 pin 13 of U106 14 25C1020 EA 25C1020 EA Shure T4 Diversity Receiver Connect power to the receiver Adjust the RF output of the signal generator RF output so that you obtain a reading of approximately 2 Vdc at TPB4 If this is unattainable even with the full 20 dBm generator output adjust IF coil L7 until you obtain a reading above 2 V If you cannot get more than 1 25 V return L7 to its
31. c voltage that varies with the amount of noise present on the detected signal 2 25C1020 EA Audio Output Peak LED Power 25C1020 EA Shure T4 Diversity Receiver Channel B This follows an identical scheme noise signals from U2 are ad justed by squelch level control R41 before being amplified by U108C filtered by U108A rectified by D107 and smoothed by C140 Comparator Circuits U106C and U106D compare the dc noise signals from the two channels When these signals are comparable U106C and U106D direct analog switches U103C Channel A and U103B Channel B to allow both channels to pass through The signals from each channel are correlated while the noise is uncor related which makes possible a theoretical signal to noise improvement of 3 dB When the dc noise signals are not comparable the channel with less noise is chosen U106A imposes an additional criterion on Channel A and U106B does the same for Channel B Each channel s dc noise voltage is compared to a threshold set by user adjustable R112 Squelch A channel whose noise exceeds this threshold is squelched If both channels exceed their thresholds the audio out put of the receiver is squelched Squelching is accomplished by tying together the outputs of U106A and U106C Channel A or U106B and U106D Channel B These outputs also control the yellow Diversity status indicators Compara tor U102 provides additional attenuation in the squelched state
32. channel while the other is squelched but these levels change significantly when both channels are ac tivated check U103 If the audio level is correct but the unit exhibits high total harmonic distortion thd vary the RF input frequency 20 kHz above and below the operating frequency If the thd drops to an acceptable level check the local oscillator frequency If it is within specifications repeak the quadrature coil L107 L108 for maximum ac output at TP5 TP8 see step 1 of Channel A Au dio page 14 step 1 of Channel B Audio page 15 On earlier units only which do not have L107 replace ceramic discriminator FL1 FL4 If the audio circuitry works properly but the red audio peak LED either fails to light when the standard test signal is applied or remains on when there is no modulation check the dc voltages at U102B U102C and U102D against those in a known working unit Also check the peak LED itself Replace any defective components 18 2501020 EA Shure T4 Diversity Receiver Notes 25C1020 EA 19 Notes Shure T4 Diversity Receiver Replacement Parts and Drawings On the next page the parts are listed according to the designations from the pc board see Figure 5 page 25 and the schematics at the end of this manual Parts shown on the circuit diagram and not listed below are available through electronic parts distributors On the pages following the parts list are the drawings of the printed cir
33. cuit boards and the schematics Product Changes This section briefly describes significant changes to the T4 Op Amps The older part for U105 U108 and U109 manufactured by Ray theon was replaced No other component changes were involved E Revisions These revisions of the pc boards temporarily changed the IF detector deleted U107 changed a number of resistors and capacitors made eight coils and a resistor frequency dependent and changed Q3 and Q8 from bipolar mixers to GaAs MESFET gallium arsenide metal semiconductor field ef fect transistor mixers FM Detector A temporary shortage of the Sanyo chip caused the temporary substitution of a Harris FM detector It used two additional resistors R174 and R175 Should you replace the Harris detector with the Sanyo unit be sure to re move those two resistors Frequencies The G version of the pc board introduced many new Euro pean frequencies five additional board groups E J and a consequent reas signment of some frequencies to different board groups The revised board re ceived both some component changes and an altered layout Quadrature Coil The extensive changes on the G pc boards referred to in the preceding paragraph included the replacement of ceramic discriminators FL1 and FL4 with quadrature coils L107 and L108 Test Points On earlier versions of the pc boards the test points were desig nated as TP1A TP1B etc on newer boards
34. e and focus your tests on the problem If this proves inconclusive or you want somewhat more extensive checks perform the following functional tests Functional Tests The following tests require partial disassembly of the unit RF Test The following is the best fast test of a receiver s RF performance A receiv er that passes this test can be removed from the list of suspects for any drop out or range problem Initial Set up 1 Set the receiver s Squelch control to its middle position and the Volume control to its maximum position 2 Set the RF signal generator to the receiver s frequency 3 Remove the receiver s antenna see Disassembly page 7 Plug the BNC end of the 50 Q test cable into the RF signal generator Tack solder the cable s center conductor to the receiver s antenna input TPA1 or TPB1 and the shield to a ground plane as close as possible to the an tenna input TPA2 or TPB2 Test 1 Connect power to the receiver and turn it on 2 Verify that the unit unsquelches with RF signals greater than 89 dBm 3 When the unit unsquelches verify that the Diversity LED glows Audio Tests Initial Set up 1 Setthe RF generator as follows Level 60 dBm Deviation 15 kHz Modulation Ext 2 Set the audio analyzer as follows Amplitude 7 4 Ving Frequency 1 kHz 3 Using a 3 3 kQ load connect the receiver s unbalanced audio output to the input of the audio analyze
35. ei N59 50 N60 113 u2 N58 267k L Ama ER e T T TP3B ve Do neg GP we DOT N62 1 Langen gg 86A8877 IDs N67 N88 G2 C54 C55 ap He OSpE LIS N69 33 2 KS 1 8 s6A8910 183A03 FLS 332 ae C53 Nes 1 i Qse C57 C78 N68 3skt31 V12 gj Wero erc I ile Mi K 1 A esa 1 el ns oe ki Ceramic Filter i me cw t durs EI 1 rEa4 C59 FM Detector IC R41 A iBpF pF S 3pF 183A23 S t ae 4U 1 e Leen lost 150pF 9 FR Lu T 27opF Ceramic Filter R42 MINE 180pF a Muting N73 ces ANS 113 4 N74 4 82A8003 82A8003 15pF RAA N76 i 10 0471 2lahials 12 3 e he TPag 56pF 337 3 L664 1 ces 9V 100 75K lon Y 48 4 N79 N77 TP4B Nat In d ze R45 Cep 066 DIS een wl L R46 C69 of GH ES la Dap 1007 T 001 001 L 499 047 wel ye T 047 G als 0 4 4 9v 047 67 82A8003 T L LC72 R49 047 NA asian Y S5 R50 047 100 gt aE 37 4K rh T4 Earlier Version Schematic 1999 Shure Brothers Inc 27C1020 SB page 1 of 2
36. ests 6 25C1020 EA Shure T4 Diversity Receiver Disassembly and Assembly To access the printed circuit pc board disassemble the receiver A CAUTION Observe precautions when handling this static sensitive device Disassembly 1 Disconnect all power to the receiver 2 Collapse the antennas and rotate them until they lie flat against the case Place the receiver upside down Remove and set aside the four screws securing the bottom of the case Figure 2 G9 x Pd Case Case mounting mounting SEES screws Antenna Ne Volume knob Antenna mounting mounting screw screw Figure 2 Bottom View of Case 3 Place the receiver in its normal operating position and rotate the anten nas to their vertical positions Note that an adhesive backed nameplate at the at the rear of the unit holds the upper and bottom parts of the case together To open the case carefully separate the upper part from the bottom part at the front of the unit Carefully swing the bottom part of the case away until the two halves are at a 90 angle to allow removal of the circuit board and antennas Figure 3 4 After the circuit board has been removed pull off and retain the Volume knob 25C1020 EA 7 Disassembly and Assembly Shure T4 Diversity Receiver Antenna Case top d Circuit board be Case bottom 7 Es m AP e I Aa YO o e g U Volume knob Pd E b bow d a S gt oe Mo
37. ies User s Guide provides a description of the unit as well as operating instructions troubleshooting suggestions and tech nical data Special Equipment and Tools In addition to the standard items described in the Service Equipment manual you will need e a wireless microphone with the same frequency usually a T1 T2 or T11 to verify that the receiver is working properly e anaudio amplifier with a high impedance input gt 10 kQ and a monitor speaker for listening tests System Operating Frequencies Each receiver s circuit board has a resistor next to the group letter A H J L that identifies the range of frequencies on which the receiver can operate see Figure 4 Table 1 shows the Group Letter and its associated frequencies Note that this chart applies only to T4 receivers Table 1 Pc Board Groups O o c Le Frequency Range 169 000 173 975 MHz 174 000 179 975 MHz 180 000 185 975 MHz 186 000 191 975 MHz 192 000 197 975 MHz 198 000 203 975 MHz 204 000 209 975 MHz 210 000 215 975 MHz 216 000 222 975 MHz 223 000 229 975 MHz 230 000 237 975 MHz rN TIO mm OO Om gt Tables 2 and 3 provide information for identifying the system frequency The Crystal Code together with the appropriate Shure model number identifies a specific operating frequency for transmitters and receivers Note that although a Crystal Code always designates a specific frequency it may be
38. inally update the label to show the new frequency and letter identi fication code Alignment Test Conditions 25C1020 EA Note To ensure proper operation obtain the crystal from Shure and verify that it operates within the frequency range of the pc board Since crystals are marked with the nominal oscillating frequency not with a letter code you can use the following equation to determine the frequency at which a receiver will operate with a given crystal Carrier Frequency 3 x nominal crystal freq in MHz 10 71 The alignment steps must be done together as a single continuous proce dure Before beginning be sure to do the setup described in the following sub section Test Conditions The following are the standard test conditions for the T4 Receiver With a 1 Phillips screwdriver remove the antennas Load the the unbalanced audio output J101 with a 3 3 kQ resistor For RF adjustments connect a 33 kQ resistor between ground and the following points Channel A TPA4 pin 13 of U1 Channel B TPB4 pin 13 of U2 Set the potentiometers as follows Volume R126 Fully CW Squelch R112 Midrange Audio level R106 and R168 Midrange Mute level R16 and R41 Midrange Test Cable 1 Obtain a 50 O coaxial cable for connecting the circuit boards to various test equipment To construct this cable see 50 O Test Cable Assembly in the Service Equipment manual Refer to Figure 4 for the locations of
39. oltage reading at TPA4 TPB4 does not vary when the RF coils are adjusted check the operation of the local oscillator If everything is working properly you should obtain a reading of 1 2 Vdc with a 95 dBm RF input signal depending upon component parameters and receiver frequency If you do not obtain this reading try the following e With the RF generator turned off use a spectrum analyzer to measure the injection level at TPA3 TPB3 for approximately 15 to 20 dBm e fthe preceding level is correct use a frequency counter to verify that the local oscillator signal is 10 7 MHz 015 MHz below the operating fre quency of the receiver Example To receive 169 445 MHz the local oscillator frequency should be 158 745 MHz 015 MHz Crystal Y100 operates at a third of this frequency or 52 915 MHz The nominal crystal frequen Cy which is stamped on the part is 3 333 kHz lower 52 911667 MHz in this example This discrepancy arises because the load reactance of the oscillator is not precisely zero If any of the RF coils will not tune properly check for frequency dependent capacitors that are missing or have the wrong value If the IF coil will not tune check C9 C52 If all the coils tune but the RF signal is low compare the dc voltages and components at RF amplifier Q1 Q6 with those of a properly working unit With TPA7 TPB7 connected to ground the selected diversity channel should be squelched and the A
40. or Set its output to the mini mum position then gradually increase the level until the Diversity B LED turns on This should occur with an RF input between 102 dBm and 87 dBm typically 95 dBm 7 Disconnect power from the receiver Remove the jumper from TPA7 and the RF input from TPB1 and TPB2 E Final Steps 1 If you were unable to align the unit refer to the Bench Checks section which follows immediately 2 When you have finished working on the unit reassemble it as described in the earlier Reassembly subsection on page 8 15 Service Procedures Shure T4 Diversity Receiver Bench Checks DC Power Tuning Muting Bench Checks Note In this section test points for Channel A are given first and the corre sponding test points for Channel B are enclosed in square brackets Check for 9 Vdc 0 35 Vdc at TP9 pin 3 of U101 e Ifthe voltage is lower than normal but not zero Check for 15 Vdc at the input of U101 pin 1 a reversed electrolytic capacitor C152 or a stage that is drawing excessive current e Ifthe voltage is zero Check for solder bridges or shorted foil traces de fective pcb e Ifthe voltage is higher than normal or the other tests prove negative Re place U101 Check for 5 Vdc 0 25 Vdc at TP8 pin 10 of U3 First check that that the RF signal is being applied to the correct diversity channel and that the other channel is being muted with the jumper If the v
41. r and engage the 400 Hz and 30 kHz fil 25C1020 EA 5 Preliminary Tests Shure T4 Diversity Receiver Tests Units that Pass ters The receiver s Volume control should still be in its maximum posi tion Verify the following receiver measurements e Audio level is 400 mMV ms 90 mV Record your measurement as a reference level for the next two steps e Thd is lt 0 75 Change the audio analyzer s frequency to 100 Hz and disengage the audio analyzer s 400 Hz filter Verify that the receiver s unbalanced audio output is within 2 dB 1 dB of the reference level recorded in step 1 Set the audio analyzer s frequency to 10 kHz Verify that the receiver s unbalanced audio output is 7 5 dB to 10 5 dB of the reference level recorded in step 1 Model T4V only Place a 150 Q load across the receiver s balanced out put then connect this output to the audio analyzer Verify that the output is 65 MVims 15 mV Remove the 150 Q load If you are finished testing the receiver remove the test cable and rein stall the antenna see Reassembly page 8 If the receiver passes these tests then it is functioning as expected and shouldn t require alignment If you did not use the customer s microphone trans mitter for these tests check it for proper operation If it also checks out of it it was not sent in with the receiver inform the customer that the product has retested within specifications Preliminary T
42. stage is double tuned by L14 and L15 and fed to Gate 2 of GaAs MESFET mixer Q8 Gate 1 receives the local os cillator injection from buffer transistor Q4 which is tuned by L7 The buffer stage helps isolate the diversity channels from one another by preventing crosstalk through the common local oscillator section IF and Audio Detection Stages Channel A L2 tunes the output of mixer Q3 to 10 7 MHz before the signal enters ceramic filter FL3 Transistor Q2 provides IF amplification to make up for the losses in the filters After passing through a second IF filter FL2 the signal enters amplifier detector U1 The detected audio from pin 6 is amplified by U105C Channel B L11 tunes the output of mixer Q8 to 10 7 MHz before the signal enters ceramic filter FL6 Transistor Q7 provides IF amplification before the signal passes through the second ceramic filter FL5 and enters amplifier detector U2 The detected audio from pin 6 is amplified by U108B Noise Operated Squelch Characteristics A noise operated squelch system provides both diversity channel selection and muting Noise signals are obtained from the additional detector outputs at pin 7 of U1 and U2 Noise Signals Channel A The squelch level control R16 adjusts the noise signal from U1 before it is amplified by U105A Active high pass filter UIOBD removes audio components that could cause false triggering The noise is then rectified by D101 and smoothed by C111 to provide a d
43. the dc input J103 The green Power LED should glow 2 Check for 9 Vdc 2x 0 35 at TP9 pin 3 of voltage regulator U101 Test Equipment Settings Service Procedures 1 Plug into the RF generator the BNC end of the 50 cable you soldered to the pcb antenna and ground Set the generator s controls as follows e 20 dBm on the receiver s operating frequency e 15 kHz FM deviation with 1 kHz modulation Activate the 400 Hz high pass and 30 kHz low pass filters on the audio analyzer 12 25C1020 EA Shure T4 Diversity Receiver UN r R Go R2 CH E Kies mu EE gt ei sou E mon C TPB2 TPB1 Group designator see Table 1 imum U101 XLR audio output connector J102 Note Used only on Presenter and Vocal Artist models L108 oj R41 e L12 B B cae Q C118 O B Power input J103 Note Use Shure PS20 or PS20E Channel B e L11 TPB3 We TP9 wm O CC ip U3 H On earlier Squelch control U107 units only R1 1 2 TPB7 09 TPA7 Channel A U1 ei f e TPA4 TPB5 e U106 1107 e TPB6 R1 6 A TP8 9 TPA5 e Note L107 and L108 are THAG Hi not found on earlier units U105 Figure 4 Major Components 25C1020 EA 13 P d A Antenna B 1 4 in Phone jack J101 Edge of case bottom Volume control Knob Crystal see Tables 2 and 3 Audio Peak red E U104 Diversity RF
44. the designations are TPA1 TPB1 etc J Frequency Code Starting in the summer of 1997 T Series transmitters and receivers tuned to 175 000 MHz have been labeled as BB rather than J The change was made to avoid confusion with the different meaning of the J designation in the LX88 and ELX88 units It is only a labeling change the units are physically the same L Frequencies The F pcb assembly mainly addresses the addition of a new L group with new European frequencies There were also a number of mi nor changes to capacitors partly small corrections mainly adaptations to simplify parts procurement and stocking Replacement Parts and Drawings 20 25C 1020 EA Shure T4 Diversity Receiver Parts Designations The following comments apply to the parts list and the schematic Resistors All resistors are surface mount with 1 40 W rating and 1 toler ance Capacitors Unless otherwise noted non polarized capacitors are surface mount NPO dielectric types with a 100 V capacity and a 5 tolerance and polar ized capacitors are tantalum types Table 1 T4 Hardware Replacement Parts Reference Designation Description Shure Part No A1 Printed Circuit Board Assembly 90 8550F In the underlined space insert the proper Group Code Letter from Table 2 or 3 page 10 E1 Antenna 95A8320 K1 Case Screws Antenna Mounts amp Antenna RPW612 Screw Kit Case
45. unting screw Figure 3 Reassembly 1 Slide the Volume knob back on note how it is keyed to the flat part of the shaft 2 Rotate the antennas to their vertical positions Place the pc board com ponent side up inside the top half of the case after feeding the anten nas through their holes make sure the notches in the case align with the Volume knob the LEDs align with the holes in the upper half of the case and that the board is fully seated on the studs Swing the two halves of the case together until they snap in place 4 Rotate the antennas until they lie flat against the case Turn the receiver upside down and secure the assembly with the four screws removed earlier Figure 2 page 7 Check that the Volume knob rotates freely Antenna Replacement The antennas can be replaced without disassembling the case Rotate the antenna you are replacing to its vertical position collapse it and remove the mounting screw through its access hole in the bottom of the case Figure 2 In sert the new antenna and start the screw from the bottom leaving it loose enough for you to rotate the entire antenna between your fingers Rotate the an tenna in this way as you lightly press it into the case until you feel the base seat in the slot of the bracket on the pc board Tighten the screw Disassembly and Assembly 8 25C1020 EA Shure T4 Diversity Receiver Service Procedures Reference Material The Shure Wireless System T Ser
46. used with differ ent Group Letters on other products 25C1020 EA 9 Service Procedures Shure T4 Diversity Receiver Service Procedures FCC Approved Operating Frequencies Table 2 ETSI Approved Operating Frequencies Group Crystal Code Freq MHz AVN 4146445 A W 171 845 B CA 176 200 B CC 177 600 C CE 182 200 C CF 183 600 D CG 186 200 E CL 192 200 F CQ 202 200 G CV 208 200 Table 3 Group Crystal Code Freq MHz A AQ 173 800 B AY 174 100 B AZ 174 500 B ZZ 174 500 B BA 174 800 B NB 175 000 B BB 175 000 B ND 176 600 B NE 177 600 C NH 182 000 C NK 183 600 C NL 184 600 C CS 184 800 C S 184 800 D NP 189 000 D NR 190 600 E NX 197 600 F NY 198 600 F NZ 200 350 F PU 201 650 F PB 203 000 G PD 204 600 J PP 217 000 J PR 218 600 J PS 219 600 L PV 232 825 L PX 233 125 L PY 234 625 L PZ 237 325 10 25C1020 EA Shure T4 Diversity Receiver Changing the Frequency The operating frequency of the T4 Receiver may be changed within a specif ic group by changing the crystal on the pc board for group information see the preceding section Check the receiver for proper operation before attempting to change its operating frequency After installing the new crystal perform the align ment procedures Then run an operational test to ensure the receiver is function ing properly F
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