Shure T2 Service Manual
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Shure T2 Service Manual

Wireless handheld transmitter
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See also: Owner's Manual , User Manual
Service Manual CHANGE NOTICE
T2 WIRELESS HANDHELD TRANSMITTER
Changes and corrections have been made to the Service Manual for the T2 handheld Transmitter. To update
your Service Manual, remove the pages identified in the tables below and replace them with the pages at-
tached to this Change Notice. Note that there are no changes to pages not specifically identified in the tables
below.
T2 HANDHELD TRANSMITTER SERVICE MANUAL REVISION HISTORY
Release
Original
Revision 1
Revision 2
Revision 3
Revision 4
Revision 5
Revision 6
Revision 7
CHANGES EFFECTIVE
REMOVE
these pages from Revision the
T2 Service Manual
E1999, Shure Incorporated
25–1018–1 (CC)
Part Number
25A1018
25B1018
25C1018
25C1018
25C1018
25C1018
25C1018
25C1018
MARCH 17, 2003
31 & 32
Shure Incorporated
222 Hartrey Avenue
Evanston IL 60202-3696 U.S.A.
T Wireless System
Date Code
QH
SB
SI
TF
TL
AF
BA
CC
these new Revision pages into the
T2 Service Manual
Color
White
Pink
White
White
White
White
White
Red
INSERT
31 & 32
Printed in U.S.A.

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  • Page 1 SERVICE MANUAL CHANGE NOTICE T2 WIRELESS HANDHELD TRANSMITTER Changes and corrections have been made to the Service Manual for the T2 handheld Transmitter. To update your Service Manual, remove the pages identified in the tables below and replace them with the pages at- tached to this Change Notice.

  • Page 2: Service Manual

    T2 Vocal Artist Microphone-Transmitter Service Manual 25C1018 (CC) Characteristics General This section tells how to service and align the Shure Vocal Artist T2 Microphone-Transmitter (Figure 1). The single-channel, crystal-con- trolled transmitter operates in the 169 z to 216 -approved models) or 173–240 -approved models) band.

  • Page 3: Circuit Description

    Shure T2 Vocal Artist Microphone Transmitter Circuit Description This unit contains two interconnected circuit boards that comprise the audio and sections, respectively. It is intended for use with the matching T3 and T4 receivers. -Approved vs. -Approved Models: Models approved by ETSI the Federal Communications Commission (assembly number 90–8690,...
  • Page 4 Shure T2 Vocal Artist Microphone Transmitter z region. Fundamental-mode crystal Y201 is tuned 10 kHz below series resonance by the series combination of frequency-netting coil L209, diode D201, capacitor C214, and capacitor divider C224 and C230. Frequency and Temperature Stability: To ensure frequency sta- bility despite changes in the battery voltage, regulated 5 Vdc bias is ap- plied to the varactor diode and to the base of Q201.
  • Page 5 Shure T2 Vocal Artist Microphone Transmitter The output power is +16.5 dBm (44.7 mW) into a 50 Ω load, at a fre- quency of 169.4445 z. At the lowest acceptable battery voltage of 6 Vdc, the final collector current drops to 15 mAdc and the output power to +13.9 dBm (24.4 mW).
  • Page 6 Shure T2 Vocal Artist Microphone Transmitter circuit (L203 and C213) capacitively coupled to a low-pass filter (C219, L206, and C218). C213 and C219 provide a capacitively tapped voltage divider for matching into the low-pass filter. Final Output ( -Approved Models) ETSI Transmitter: This can deliver up to +11.5 dBm (14 milliwatts) to the...
  • Page 7 Shure T2 Vocal Artist Microphone Transmitter Notes Notes 25C1018 (CC)
  • Page 8 Tests 1. Install a fresh 9 V battery in the T2, mute its audio, and turn it on. 2. Measure current drain: it should not exceed 35 mA. 3. Maximize the signal received on the spectrum analyzer by at- taching a telescoping whip antenna to it.
  • Page 9 Make sure the receiver’s Volume control is at its maximum setting. 2. Replace the microphone cartridge on the T2 with the test head. Set the unit’s Gain control to minimum and unmute the audio. 3. Inject a 775 mV, 1 kHz signal from the audio analyzer into the adapter cable and verify the following: the amplitude from receiver’s unbalanced output equals...

  • Page 10: Disassembly And Assembly

    Shure T2 Vocal Artist Microphone Transmitter Disassembly and Assembly To access the printed circuit (pc) boards, disassemble the transmitter (refer to Figures 2 and 3 on pages 9 and 10). CAUTION Observe precautions when handling this static-sensitive device. Disassembly 1. Turn off the Power switch.
  • Page 11 Shure T2 Vocal Artist Microphone Transmitter Reassembly 1. Insert the transmitter subassembly (audio, , and head circuit boards) into the internal guides of the handle (Figure 3). 2. Orient the retaining ring so its gap will fit over the flat edge of the head board (to avoid shorting the board).

  • Page 12: Service Procedures

    Each transmitter circuit board is marked with a group letter that iden- tifies the range of frequencies on which the transmitter can operate. Note that Table 1 applies only to T2 transmitters that are -approved, and Table 2 applies only to T2 transmitters that are -approved.
  • Page 13 (pcb marking 34A8538). Tables 3 and 4 provide information for identifying the system fre- quency. The Crystal Letter Code, when used with the appropriate Shure model number, identifies a specific operating frequency for both transmit- ters and receivers. Note that, although a Crystal Letter Code always des- ignates a specific frequency, it may be used with different Group Letters on other products.
  • Page 14 (pcb marking 34A8538). Changing the Frequency The operating frequency of the T2 transmitter may be changed with- in a specific Group by changing the crystal on the pc board. (For Group information, see the preceding subsection). Check the transmitter for proper operation before changing its operating frequency.
  • Page 15 Shure T2 Vocal Artist Microphone Transmitter 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 transmitter will operate with a given crystal: Carrier Frequency = (9 x nominal crystal freq.
  • Page 16 Shure T2 Vocal Artist Microphone Transmitter 2. Tack-solder the cable to side 1 of the circuit board as follows: Center conductor to the 50 Ω solder pad, I210 Shielding to (on older versions, IGND) ETSI-Approved Units 1. Obtain a 50 Ω coaxial test cable for connecting the circuit boards to various test equipment.
  • Page 17 Shure T2 Vocal Artist Microphone Transmitter Audio Board (top) Power Low battery (green) (red) R125 C107 D103 D101 U101 J102 Ç – Ç Ç Ç J101 Power U102 R130 On/Off On/Off S102 S101 Head Board (front view) +9 V (to cartridge)
  • Page 18 1. Make sure that the Mic switch (S102) is turned to ”Off.” 2. On the spectrum analyzer, set the center frequency to the fre- quency of the T2. Then make the following settings: Span: 1 MHz Reference level: +20 dBm Scale: 10 dB/div.
  • Page 19 6 (before antenna-matching). end of the 50 Ω cable into the spectrum analyzer. 4. Plug the 5. Set the center frequency to the frequency of the T2. 6. Adjust C216 and C222 for maximum (peak) output power on the spectrum analyzer.
  • Page 20 The audio board has changed relatively little in the history of the T2. Two examples of changes are the renumbering of the...
  • Page 21 H: Deviation Reference Voltage 1. Turn off the T2 Power switch. 2. Obtain a receiver set to the same frequency as the T2 (this will probably be the T3 or T4 that came with the T2). Note: Alternatively, use a modified 4 receiver for any transmit- ter.
  • Page 22 Shure T2 Vocal Artist Microphone Transmitter 4. Make sure that the receiver’s yellow lights. RF LED 5. Set the receiver’s Volume control to the maximum position (full clockwise rotation) and apply power to the receiver. On the T4, set the Squelch control to its midpoint.
  • Page 23 Shure T2 Vocal Artist Microphone Transmitter Notes Notes 25C1018 (CC)
  • Page 24 Shure T2 Vocal Artist Microphone Transmitter Bench Checks The tests for power and audio apply to all T2 units. Those involving board differ for -approved and -approved units; hence ETSI this section includes two separate sets of procedures for testing.
  • Page 25 Shure T2 Vocal Artist Microphone Transmitter n Check the connections from pin 14 of U102 to the next stage, to the limiter (Q103), and to pin 15 of U101. n Check the bias voltage (`4 Vdc) on pins 8, 9, and 10 of U102. If the correct voltage is not present: Make sure the Mic switch is set to “On.”...
  • Page 26 Shure T2 Vocal Artist Microphone Transmitter n Make sure the Board Group is the correct one for the desired frequency. n Stage 1: Make sure that rotating C217 360 degrees in either di- rection produces two separate peaks in the carrier output ampli- tude.
  • Page 27 Shure T2 Vocal Artist Microphone Transmitter Frequency Problem: -Approved Units ETSI n Make sure the carrier is at least 10 dB higher than the spuri- ous emissions, to allow the frequency counter to lock on. n Check L201 for the proper group and make sure its core is not cracked.
  • Page 28 Shure T2 Vocal Artist Microphone Transmitter n If the power is slightly low and the spurious level is high, check for wrong or open coils at L205, L207, and L210. n Check the collector bypass capacitors for the stages (C220,...
  • Page 29 Shure T2 Vocal Artist Microphone Transmitter Distortion: -Approved Units ETSI n Make sure the analyzer’s 400 Hz high-pass and 30 kHz low- pass filters are pressed in. n Pin 9 of U101 should read about 1.8 Vdc. n As you turn R139, the dc level on its wiper should change from about 1.5 V to 3.5 V.
  • Page 30 Shure T2 Vocal Artist Microphone Transmitter Replacement Parts and Drawings On the next page, the parts are listed according to the reference designations from the pc boards and schematics. Parts shown on the circuit diagram and not listed below are available at most electronic parts distributors.
  • Page 31 Shure T2 Vocal Artist Microphone Transmitter Parts Designations The following comments apply to the parts list and the schematic: Resistors: All are surface-mount, W rating, and 1% tolerance. Capacitors: Unless otherwise noted, non-polarized capacitors are surface-mount dielectric types with a 100 V capacity and 5% toler- ance;...
  • Page 32 Shure T2 Vocal Artist Microphone Transmitter Table 1 T2 Replacement Parts Reference Designation Description Shure Part No. -approved pro- T90__8690 RF/Audio grammed circuit board assembly [in the underlined space, insert the proper frequency code-letters from Table 3 page 12, —e.g., T90CA8690]...
  • Page 33 Shure T2 Vocal Artist Microphone Transmitter Reference Designation Description Shure Part No. Audio Circuit Board (both models) D101 LED, red (low battery) 184A18 D103 green (power) 184D18 LED, Q103, Q104 transistor, MMBT5087L 183A01 Q105 transistor, 2SA1252 183A07 Q106, Q107, transistor, MMBT5089L...
  • Page 34 Shure T2 Vocal Artist Microphone Transmitter Audio Board (top) Audio Board (bottom) Figure 6. T2 Audio Board -Approved Board (top) -Approved Board (bottom) Figure 7. T2 -Approved Board 25C1018 (CC) Replacement Parts and Drawings...
  • Page 35 Shure T2 Vocal Artist Microphone Transmitter -Approved Board (top) ETSI R252 R253 R256 R257 Group “K” is indicated by resistors at “G” and “H” (R256 and R257). -Approved Board (bottom) ETSI Figure 8. T2 -Approved Board ETSI Replacement Parts and Drawings...
  • Page 36 Shure T2 Vocal Artist Microphone Transmitter Older Version Audio Board (top) Older Version Audio Board (bottom) Older Version Board (bottom) 50 Ω cable IGND Older Version Board (bottom) Figure 9. T2 Older Version Boards 25C1018 (CC) Replacement Parts and Drawings...
  • Page 37 Shure T2 Vocal Artist Microphone Transmitter Schematics (Note to Printer: do not print this page) Please print the attached schematics in the order they are listed: T2 Earlier Version Audio Board (letter size) T2 Earlier Version Board (letter size) T2 Audio Board (ledger size) –approved...
  • Page 38 I47 = +5V DC TO RF BOARD J102 188A01 1.8uH I40 = Vcc INPUT (+9V DC) C128 Q106 Q107 I45 = GROUND 150pF 183A02 183A02 R138 R139 U101 C129 150pF AUDIO GROUND E 1999, Shure Brothers Inc. T2 Earlier Version Audio Board 27B1018 (SB)
  • Page 39 D101 R145 18.2K 188A01 60.4K 183A02 C128 150pF Q108 U101 183A02 C129 183A02 150pF Q107 Q110 Q106 183A02 183A02 150pF R139 R138 C132 R146 6.81K 4.99K 6.81K E 1999, Shure Brothers Inc. T2 Audio Board I1GN Audio Ground 27B1018 (SB)
  • Page 40 150DA150JA GROUP B 184.000 – 199.000 MHz 152D01 4–20 150DA150JA 150DA220JA 150DA509CA 150DA100CA –– 150DA120JA GROUP C 199.000 – 216.000 MHz 152D01 4–20 150DA120JA 150DA180KA 150DA108CA 150DA688CA –– 150DA828CA E 1999, Shure Brothers Inc. T2 Earlier Version Board 27B1018 (SB)
  • Page 41 150DB220JA 150DB509BA 150DB828CA 150DB478CA 150DB150JA GROUP B 184.000-198.975 MHz 152D02 4-20 150DB150JA 150DB220JA 150DB509BA 150DB100JA 150DB120JA GROUP C 199.000-215.975 MHz 152D02 4-20 150DB120JA 150DB180JA 150DB108BA 150DB688CA 150DB828CA T2 FCC -Approved RF Board 1999, Shure Brothers Inc. (from 90_8690D-11) 27B1018 (SB)
  • Page 42 Frequency Groups E 1999, Shure Brothers Inc. T2 ETSI -Approved RF Board 27B1018 (SB)
  • Page 43 2. Electrolytic capacitors are shown in mF  volts unless otherwise specified. 3. All voltages shown are dc. Rf ground is indicated by the symbol 4. The “K” Group is marked by R256 and R257 (“G” and “H” resistors). T2 ETSI -Approved RF Board E 1999, Shure Brothers Inc. (from 90_8705D-11)

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