shure_t_1 电路图.pdf

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1、Shure Incorporated 222 Hartrey Avenue Evanston IL 60202-3696 U.S.A. T Wireless System ?1999, Shure Incorporated Printed in U.S.A. 2510161 (CC) SERVICE MANUAL CHANGE NOTICE T1/TC1 WIRELESS BODY-PACK TRANSMITTER Changes and corrections have been made to the Service Manual for the T1 Body-Pack Transmit

2、ter. To up- date 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. T1 BODY-PACK TRANSMITTER SERVICE MANUAL REVISION HISTORY Rele

3、asePart NumberDate CodeColor Original25A1016QHWhite Revision 125B1016SBPink Revision 225C1016SIWhite Revision 325C1016TLWhite Revision 425C1016AFWhite Revision 525C1016BAWhite Revision 625C1016CCRed CHANGES EFFECTIVE MARCH 17, 2003 REMOVE these pages from the T1 Service Manual INSERT these new Revis

4、ion pages into the T1 Service Manual Page 22Page 22 RadioFans.CN 收音机爱 好者资料库 1Characteristics25C1016 (CC) T1/TC1 Body-Pack Transmitters 25C1016 (CC) Characteristics General This section tells how to service and align the T1G, T1, TC1, and the discontinued T1P Body-Pack Transmitters (Figure 1). These

5、single-chan- nel, crystal-controlled units operate in the 169 MHz to 216 MHz VHF Band. Guitarist T1G and TC1 Trans- mitter Presenter T1 Transmitter Presenter T1P Transmitter (discontinued model) 1 2 3 4 Figure 1. 1. Phone jack 1/4? (guitar or headset input) 2. Antenna 3. Tini “Q-G” (Lavalier, headse

6、t, WA302 input) 4. Lavalier microphone Service Note: Shure recommends that all service procedures be performed by a factory-authorized service center or returned directly to Shure Brothers Inc. Licensing: Operation may require a user license. Frequency or power-output modifications may violate this

7、products approvals. Contact your countrys communications authorities. ?1999, Shure, Inc. Printed in U.S.A. RadioFans.CN 收音机爱 好者资料库 Shure T1 Body-Pack Transmitters 2Characteristics25C1016 (CC) Circuit Description The T1 transmitter contains one circuit board which comprises an audio and an RFsection.

8、 It is intended for use with the matching T3 and T4 receivers. Audio Section Input: Audio signals enter via a 1/4-in. phone jack, with the signal on the tip and the ground on the ring (T1G), an attached microphone (the discontinued model T1P), or a four-pin, Tini Q-G, connector (T1): ?Pin 1: Ground

9、?Pin 2: Supplies regulated 5 Vdc bias for electret condenser mi- crophones ?Pin 3: Audio input ?Pin 4: 20 k load resistor connected to pin 3 for Shure electret microphones Preamplifier Stage: This is centered in one section of the operation- al amplifier (U102C). An externally accessible potentiomet

10、er (R125) ad- justs the voltage gain of this stage over a 40 dB range. Passive Pre-emphasis Network and Compandor: The network (R145, C110, C111, R112, and R115) has a pole at 63 microseconds and a zero at 1 microsecond. The NE571D integrated circuit compandor (U101A) provides a 2:1 logarithmic comp

11、ression of the audio signal. Noise and Distortion: U102A lowers the noise floor, and an internal potentiometer (R130) nulls the system audio distortion. Operational am- plifier U102B, operating as a two-pole, active, low-pass filter, restricts the bandwidth of the system to audio frequencies. Limiti

12、ng: PNP transistors Q103 and Q104 limit the level of the audio signal leaving the audio section via U102B. Beginning in July 1995, this section was removed from the “A,” “B,” and “C” boards but left in a newly designated “T” board. 5 Vdc Bias and LED Drive Circuits: The NE571Ds identical second chan

13、nel (U101B) supplies regulated, low-noise 5 Vdc bias to various audio and RF circuit points. Transistor Q105 provides “reverse battery protection” to the circuit. Q106 drives LED D101 (“Power On”), and Q107 drives LED D102 (“Low Battery”). RF Section Audio Input: Processed audio enters R217, an inte

14、rnal potentiom- eter that is adjusted for 15 kHz deviation (100% modulation) when the audio section provides a 2.2 dBV, 1 kHz tone. Oscillation: The audio then goes to varactor diode D201, which is part of the modulated oscillator-tripler stage (Q201). The latters base- emitter circuit operates as a

15、 crystal-controlled Colpitts oscillator in the 20 MHz region. Fundamental-mode crystal Y201 is tuned 10 kHz below series resonance by the series combination of frequency-netting coil RadioFans.CN 收音机爱 好者资料库 Shure T1 Body-Pack Transmitters 3Characteristics25C1016 (CC) L209, diode D201, capacitor C214

16、, 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. Temperature com- pensation is provided by C224, C230, and C214. Tuned C

17、ircuits Stage 1: The collector circuit of Q201 is tuned to the third harmonic of the oscillator frequency (approximately 60 MHz) by L205, C225, C234, L202, C217, and C233. (The latter components also form a capacitively- tapped voltage divider for matching the signal to the base of Q203.) The output

18、 is double-tuned to provide high-spectral purity. Regulated dc bias is again employed to minimize changes in loading on the oscillator stage and to stabilize the drive levels. Stage 2: Q203 operates as a frequency tripler, with its collector cir- cuit tuned to the output frequency (for example, 180

19、MHz). In this case, L204, C215, C237, C236, L207, C235, and C222 perform tuning and impedance-matching functions. As in the preceding stage, regulated dc bias is applied to the base circuit to stabilize the drive level, and the output is double-tuned to provide spectral purity. Stage 3: Q204 operate

20、s as a tuned amplifier. Resistive loading on the input provides stability. The output circuit consists of a resonant tank 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-pa

21、ss filter. Transmitter Output Transmitter: This can deliver up to +17 dBm (50 mW) to the an- tenna. No user adjustment permits this value to be exceeded. The unit should be powered exclusively by a 9 Vdc dry battery (an alkaline type, such as a Duracell MN1604, is recommended). Voltage Measurements:

22、 With 9 Vdc applied to the unit, the fol- lowing voltages should appear at the terminals of the output transistor; ?Vc = 8.88 Vdc ?Vb = .450 Vdc ?Ve = .473 Vdc. ?Base current = .29 mAdc ?Emitter current = 21.5 mAdc ?Collector current = 21.8 mAdc ?Power input = 183 mW The output power is +16.5 dBm (4

23、4.7 mW) into a 50 load, at a fre- quency of 169.445 MHz. At the minimum acceptable battery voltage of 6 Vdc, the final collector current drops to 15 mAdc and the output power declines to +13.9 dBm (24.4 mW). Shure T1 Body-Pack Transmitters 4Characteristics25C1016 (CC) Antenna: This is a quarter-wave

24、length, permanently attached, flex- ible wire. The ground plane of the circuit serves as an untuned counter- poise capacitively coupled to the body of the user. Spurious Emissions: To minimize the production and radiation of spurious emissions and harmonic energy, and to promote stable opera- tion,

25、the collector of each RF stage is separately decoupled from the 9-volt supply by ferrite chokes, resistors, and bypass capacitors. The base circuits are similarly decoupled except that they use resistor-capac- itor (R-C) networks, whose higher-impedance levels are more appropri- ate. Shure T1 Body-P

26、ack Transmitters 5Preliminary Tests25C1016 (CC) Preliminary Tests Listening Tests Before disassembling the unit, operate it to determine whether it is functioning normally. Focused Testing: First and most important: Review any customer complaint or request and focus your listening and functional tes

27、ts on any reported problem. For example, for “short range” and “drop-outs” com- plaints, perform only the RF tests in this section. If the unit passes these, there is a strong indication that the customer is using the product incor- rectly (e.g., not keeping the transmitter in the receivers line of

28、sight, not avoiding metal enclosures or TV interference). Return the unit to the cus- tomer together with an explanation of the proper set-up procedures. For complaints of distortion or other audio problems, try a “standard” lavalier or headset microphone (you should have one of each micro- phone on

29、-hand for testing) and perform the audio tests in this section. Functional Tests RF Tests 1.Remove the case top, mute the audio, and apply 9 Vdc to the battery terminals. 2.Measure the current drain: it should not exceed 35 mA. 3.Maximize the signal received on the spectrum analyzer by at- taching a

30、 telescoping whip antenna to it. Then measure the near-field output power: it should be ?7 dBm. (If you are unsure of the results you obtain here, measure the output power conductively by soldering a 50 cable to the out- put of the transmitter. Verify that the output power is 15 dBm, ?2 dBm.) 4.Veri

31、fy that the carrier frequency of the transmitter varies from its nominal value by no more than ?6 kHz. 5.Check for an intermittent problem by shaking the transmitter and tapping on it. As you do so, try to keep it at a constant distance from the spectrum analyzer. Verify that the output power on the

32、 spectrum analyzer shows no large and sudden drops in power level (it will, however, vary a few dB with hand position). 6.Turn off the transmitter. If the transmitter passes the above tests, its RF circuits are working as designed. Audio Tests A: Verify the Matching Receiver 1.Connect the signal gen

33、erator to the receiver through a 50 cable. Tack-solder the center conductor to the antenna input and ground the shield of the cable to pcb ground. Shure T1 Body-Pack Transmitters 6Preliminary Tests25C1016 (CC) 2.Set the RF generator as follows: Amplitude: 20 dBm Modulation: 1 kHz Deviation: 15 kHz F

34、requency: T1 operating frequency 3.Connect the audio from the unbalanced output to the audio ana- lyzer with a 3.3 k load. Turn the Volume control all the way up. 4.For the associated T3 or T4, verify the following: ?audio level is 400 mVrms (?90 mV) ?thd = 0.75% B: Check the Transmitter 1.Disconnec

35、t the signal generator from the receiver. Monitor the receivers unbalanced audio output with a 3.3 k load and the audio analyzer. Check that the receivers Volume control is still at its maximum setting. 2.Unmute the transmitter and turn its gain to the minimum setting. Connect an input cable as foll

36、ows: T1 and T1G: Use adapter cables to input the audio to the body- pack input. T1P: Disassemble the case, remove the microphone, and attach the adapter cable to the four-pin header of the audio input. 3.Inject a 775 mV, 1 kHz signal from the audio analyzer into the adapter cable and verify the foll

37、owing: ?the amplitude from receivers unbalanced output equals 400 mVrms (?90 mV) ?thd = 0.75% 4.Change the frequency of the audio generator to 100 Hz and dis- engage the 400 Hz high-pass filter from the audio analyzer. Verify that the audio level is 1 dB (?0.7 dB) relative to the level measured in s

38、tep 3. 5.Change the frequency of the audio generator to 10 kHz and re- engage the 400 Hz high-pass filter. Verify that the audio level, relative to that measured in step 3, is 0 dB, ?1 dB. Units That Pass If the system components pass these tests and the microphone is good, then the system is functi

39、oning as expected and shouldnt require tuning and alignment. Inform the customer that the product has retested within specifications. Shure T1 Body-Pack Transmitters 7Disassembly and Assembly25C1016 (CC) Disassembly and Assembly To access the printed circuit (pc) board, disassemble the transmitter.

40、CAUTION Observe precautions when handling this static-sensitive device. Disassembly 1.Slide open the battery-compartment cover and remove the bat- tery. 2.With a #1 Phillips screwdriver, remove the four screws securing the back of the case, and set them aside. 3.Carefully separate the top and bottom

41、 halves of the case to ex- pose and lift out the pc board. (If you have trouble separating the case, carefully slit the label covering the case separation inside the battery compartment.) Reassembly Reassemble the T1 Transmitter as follows: 1.Presenter T1P transmitter only: Plug the lavalier microph

42、one connector into J104. 2.Place the pc board in the bottom half of the case. 3.Slide the battery-compartment cover into its slot. 4.Align the rubber grommets (antenna, lavalier) while positioning the top half of the case over the bottom half. 5.Make sure the two sections are properly seated before

43、securing them with the four Phillips screws. Shure T1 Body-Pack Transmitters 8Disassembly and Assembly25C1016 (CC) Converting a T1P to a T1 Because direct replacements for the lavalier microphones used in the T1P are no longer available, the best way of replacing the micro- phones in these earlier u

44、nits is to replace the lavalier header with a male Tini Q-G connector, which will allow the unit to accept a WL93 or other microphone that has a mating connector. Changing the connectors in effect converts the T1P into a T1 unit. Parts Needed Microphone with a female Tini Q-G connector (e.g., Shure

45、WL93). Part order RPW262 for all the following items: ?male Tini Q-G connector with a pcb assembly ?spacer ?nut Conversion Procedures 1.After separating the two halves of the case, remove the pc board and the microphone. Pull the female connector wired to the mi- crophone from the pcb header, J104.

46、2.Remove the header by unsoldering its four pins from the bottom of the pcb (the side with fewer components). Make sure the four holes in the pcb are open. 3.Orient the pcb assembly with the top (major-component) side up, the switches and LEDs to the left, and the antenna to the right. 4.Pull off th

47、e pre-cut insulation from the ends of the connector as- semblys ribbon cable. From the top of the transmitter board, insert the cable wires into the four holes vacated by the header: the black coded lead goes into the hole nearest the right edge of the pcb (towards the pcb number). 5.Solder the wire

48、s to the bottom of the pcb and cut off the exces- sive leads. 6.After replacing the transmitters pcb in the bottom half of the case, insert the connector into the front slot. Place the spacer and start the nut on the part of the connector that protrudes from the case. 7.After completing the reassembly, tighten the nut on the Tini Q-G connector. Shure T1 Body-Pack Transmitters 9Service Procedures25C1016 (CC) Service Procedures Reference Material The Shure Wireless Systems: T Series Users Guide provides a de- scription, information on operation and troubleshooting, and technical data. Sp