Sansui-TU70-tun-sm 电路图 维修手册.pdf

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1、OPERATING INSTRUCTIONS . . . . . . . . . . . . . 9 HINTS ON USE . 10, 11, 12 SERVICE NOTE . 13, 14, 15 PARTS LIST . 16, 17, 18 ALIGNMENT. . . . . . . . . . . . . . . . . 19, 20 SCHEMATIC DIAGRAM . 21 PARTS LAYOUT/DIAL CORD STRING. 22 RadioFans.CN 收音机爱 好者资料库 SUI AM /FM MULTIPLEX STEREO TUNER * MODEL

2、TU-70 RadioFans.CN 收音机爱 好者资料库 FEA TURES SPECIFICATIONS CHARACTERISTICS FEA TURES FM HIGHLY SENSITIVE TWO-STAGE RF AMPLIFIER USING TWO NUVISTORS AND THREE-GANG VARIABLE CONDENSER This top-quality, super-sensitive tuner fully in- corporates the best of Sansuis techniques as demonstrated by the RF ampl

3、ifier consisting of two Nuvistors. Read these instructions carefully before you use the tuner for the first time. The TU-70 tuner has an extremely compact, high-gain RF amplifier for FM which uses two cascade- coupled, low-noise Nuvistor tubes with a three- gang variable condenser. Therefore, the tu

4、ner outperforms conventional single-stage grounded- grid RF amplifiers by 10 db in amplification and assures stable, high-selectivity, high fidelity reception. The TU -70 tuner has sensitivity characteristics of 1.2 microvolts at 20-dB quieting 100% mod- ulation and 1.8 microvolts at 30-clB quieting

5、 100% modulation. Unwanted radio waves are so neg- ligible that they do not interfere with TV and other receivers. DOUBLE-LIMITER SHUTS OUT NOISES The TU-70 tuner is equipped with a two-stage noise limiter, which works effectively even where the field intensity is weak. It reliably eliminates a wide

6、 variety of noises such as annoying ignition sounds and other interference. MUTING SWITCH SUPPRESSES NOISE DURING CHANNEL SELECTION Unlike conventional FM receivers, which produce loud noise in the absence of input because their limiters require a certain level of input voltage to perform their nois

7、e-limiting function, the. TU- 70 tuner produces no noise even when not tuned to any station. This is because it has a built-in -3- muting switch (squelch circuit) which discon- nects the audio amplifier stage automatically when tuner input drops below a certain leveL. AMAZING CHANNEL SEPARATION OF 3

8、7DB AND MORE ENSURED BY ADVANCED FM MULTIPLEX CIRCUIT The adoption of the most advanced switching matrix method for the multiplex circuit has amazingly improved the performance of the TU -70 tuner. Channel separation is minimum 37 dB at 1 kc and distortion is maximum 1% at 1 kc. FULL-FLEDGED AUTOMAT

9、IC FREQUENCY CONTROL (AFC) The TU-70 has a full-fledged AFC, which can be switched off if you like. The AFC enables you to enjoy a stabilized reception of FM broad- casts for many hours once you have tuned to. EASY-TO-SEE FM MULTIPLEX STEREO INDICATOR The FM Multiplex Stereo Indicator actuated by pr

10、ecision transistors helps you tune to FM stereo stations easily and reliably. AM SINGLE-STAGE RF AMPLIFIER WITH THREE-GANG VARIABLE CONDENSER The addition of a single-stage RF amplifier to the AM tuner has improved its sensivity remark- ably. This makes it particularly useful for DX reception. Moreo

11、ver, it has such an excellent image ratio that no beat is produced between your station and another neighboring station. BUILT-IN, HIGH-SENSITIVITY FERRITE ANTENNA The built-in, high-sensivity ferrite antenna adds to your listening pleasure by reducing noise to less than that of conventional tuners.

12、 * All rights reserve specifications subject to change without notice. Can be switched on and off (-13.5dB,10kc) Can be switched on and off Can be switched on and off FM stereo indicator (actuated by transistors), Tuning indicator Power consumption 60 volt-amperes Power requirements AC 100, 117, 220

13、 or 240 volts, 50/60 cps Width 405 mm (15. 95) Depth 320 mm (12. 60) Height 142 mm (5. 59) 7.5 kg (16.5 Ibs) SPECIFICA TIONS Tubes and Diodes (14 tubes and 13 diodes) FM Tuner Frequency range Bandwidth Intermediate frequency Sensitivity Image ratio Frequency response characteristics Distortion AM Tu

14、ner Frequency range Bandwidth Intermediate frequency Sensitivity Image ratio FM Multiplex Frequency response characteristics Channel separatlon Distortion Output Level Accessory Circuits Noise filter Muting circuit AFC circuit Indicators Size Weight CHARACTERISTICS 6CW4 (Nuvistor) X 2, 6AQ8 x 3, 6AU

15、6 x 2, 6BA6 x 3, 6BE6 xl, 6Bl8x1, 6R-E13x1, 12AU7xl, OA-81 (Ge diode) X 10, MA-311 (VC) xl, SD-1 B (Si diode) FM MPX DISTJRTION CHARACTERISTICS 10 9 a 7 i 5 e , O2 , III TT. Iii COMPOSITE STEREO SIGNAL i V( rms) -lE FT CHANNEl- -RIGHT CHANNEL I- I- ,. 88108 Mc 230 kc (- 3 dB) 10 la FREQUENCY (Hz) 10

16、.7 Mc 1.8 microvolts at 30-dB quiet- ing IHFM 1.2 microvolts at 20-dB quiet- ing 100 % modulation (300 D) 1.1 microvolts at 30-dB quist- ing 100% m:dulation (75D) min. 52 dB FM MPX CHANNEL SEPARATION - COMPOSITE STEREO SiGNAL i V(rms) IIIIIIIII - LEFT CHANNL - RIGHT CHANNEL - -IO Z o -20 -3Q 10 10 F

17、REQUENCY (Hz) I:; :t2 dB, 30 cps-15 kc max. 1 % at 100 % modulation FM SIN RATIO ;30 20 455 kc 6 microvolts at 20-dB SIN ratio, 30 % modulation min. 75 dB 3pV10 IpV 0 a.spy -10 20 40 00 ao ANT INPUT (dB) FM 1FT CHARACTERISTICSDISCRIMINATOR CHARACTERISTICS :t2dB,30cps-15kc 37 dB at 1 kc . max. 1 % at

18、 1 kc min. 1.2 volts at FM stereo and monaural input of 10. microvolts or over, 30% modulation =-2 AM 1FT CHARACTERISTICSPRACTICAL AM SENSITVITY IMAGE FATIO 00 30 20 -4- CONNECTIONS ANTENNAS AM ANTENNA As ilustrated below, pull the ferrite bar antenna A toward you on the axis b. Observing the tuning

19、 indicator, set this antenna for the best reception place. If it is not possible to get a reasonable reception, untighten one of the screws which are fastened to the chassis, and turn the whole antenna for the best reception. (Fig. 3) This ferrite antenna is designed to be good enough for all recept

20、ions, except when the station signal js extremely weak due to excessively long distance from your desired station, topography, etc. For the ferrite antenna inadequate to the weak radio reception, connect the AM antenna (PVC wire) to the terminal AM-A and a ground wire to AM-E. To install, support it

21、 horizontally and apart from your building as shown in Fig. 2 and set it for the finest reception. Note that the antenna sensitivity depends largely on the position to which the antenna is installed. For safety reason, be sure to install a lightning arres- ter with the outdoor antenna. FM ANTENNA Co

22、nnect the FM antenna (fader wire) to the terminals FM:AI and -A2. If youlive near the station or the signal is strong, put it lip like T in your room. If you live in a thick-wall building or far away from your desired station and if the signal is too weak to recive with the indoor antenna, install a

23、n outdoor antenna exclusively for FM reception as shown in Fig. 1. Remember that the proper height and direction (not length) of the antenna are vital to the best reception. -5- AMPLIFIER OR STEREO SET This tuner alone cannot reproduce FM signals it receives. It must be connected to an amplifier, or

24、 a stereo set which has no FM or AM tuner. L Connecting to a Control Amplifier Connect the OUT terminal of your TU-70 to the TUNER or AUX terminal of the preamp/power amplifier-e.g. Sansui AU-70-with a shieldwire. 2. Connecting to a Pre-amplifier Connect the OUT terminal of your TU-70 tuner to the T

25、UNER or AUX ter- minal of the pre-amplifier with a shieldwire. In this case, you have to connect a power amplifier to the pre-amplifier. 4. POWER AMPLIFIER 3. Connecting to a Stereo Set or Radio Connect the OUT terminals of your TU -70 to the AUX or TUNER terminals of the stereo set with shield wire

26、. If the stereo set has neither TUNER nor AUX ter- minal, use the PHONO terminal (for iys- tal player input): 4. Connecting to a Power Amplifier Connect the OUT terminal of your TU70 tuner to the input terminal . of the power amplifier (the pre-amplifier section which has no tone control circuit) e.

27、g. Sansui Q-55- with a shieldwire. In this case, you might not get satisfactory results when the output level of the TU-70 tuner does not match the input level of the amplifier. Moreover, an amplifier without a 1. CONTROL AMPLIFIER .Au.iii rAU-70 -6- CONNECTIONS tone control or filter circuit might

28、not be us- able, particularly when the noise level is high. N.B.-Read the instructions for the stereo set, amplifier; or other equipment you use so that there can be no error in connection or operation. If the input terminal of the stereo set or other equipment is not the pin-jack type, make the nec

29、essary connections as follows: Connect the conductor with the shield wire to (+) of the input terminals or to the PU terminaL. Connect the metal sheath of the shieldwire to (-) of the input terminals or to the E terminaL. In case of monaural opera- tion, you can use either L or R terminal for the co

30、nnection. FM LOCAL /DISTANT SWITCH (Item HINTS ON USE in the catalogue) LEVEL ADJUSTMENT (Item HINTS ON USE in the cataiogue) -7- CONNECTING TO A TAPE RECORDER You can use the tuner for recording by connecting its output terminals to a tape recorders input terminals. To do this, connect the output t

31、erminals of the TU -70 to the LINE in -puts of a tape recorder. With a monaural tape recorder, you can use either L or R terminal for the connection. With a stereo tape recorder, use both Rand L terminals. In this case, you can get the same signals from both Rand L even when tuned to a monaural broa

32、dcast. Tope recorder SWITCHES AND CONTROLS CD FM MULTIPLEX STEREO INDICATOR When the tuner receives signals from an FM Station broadcasting multiplex, this indicator lights up to show that it is receiving a stereo broad- cast. The indicator never lights when the tuner is receiving a monaural FM broa

33、dcast. CI TUNING INDICATOR This closes when you have tuned to a station, whether FM or AM. Set the tuning dial at the point where the indicator closes as much as pos- sible. CI DIAL SCALE The upper figures are for FM and the lower for AM. For tuning, turn the TUNING knob. SELECTOR Use this switch to

34、 set the tuner to the broadcast of your choice. AM: for reception of medium-wave broadcasts. FM: for rception of FM broadcasts. MPX: for reception of FM multiplex stereo broadcasts. CI NOISE FILTER Turn this switch on to eliminate the noise when using your tuner in a ferroconcrete building, a block

35、occupied by such buildings Or an area of weak field intensity where you are likely to suffer from noise. CI MUTING Turn this switch on to eliminate the noise you hear when not tuned to any station. Keep it on while tuning. However, if the muting switch is kept on when you receive weak signals, the s

36、ound may be distorted or reception may become impossible. In such a case, switch off the muting circuit. (j FM-AFC This prevents signals from an FM station from drifting. This is likely to happen because of the very high frequencies used. If it occurs, the tonal quality deteriorates or you cannot he

37、ar the program at alL. To avoid this, switch on the FM-AFC after tuning in the station of your choice. If you switch on the FM-AFC before tuning, you may not be able to tune in accurately. If the FM-AFC is kept on even when there are a number of stations nearby, you may suffer from their interferenc

38、e. In such a case, switch off the FM-AFC. CI POWER This pushbutton is used to switch the tuner on and off. Push to switch on and push again to switch off. CI TUNING This knob is used to tune in FM or AM station:;. -8- OPERA TIONS AM BROADCAST RECEPTION 1. Set the SELECTOR switch at AM. 2_ Adjust the

39、 amplifier, stereo set or other equipment so that it can operate with the tuner. 3. Set the mplifier, stereo set or other equip- ment to monaural operation. 4. Tune to the station of your choice by means of the TUNING knob using the dial and the Tuning Indicator. 5. Use other switches according to y

40、our needs. FM BROADCAST RECEPTION i. Set the SELECTOR switch at FM. 2. Adjust the amplifier, stereo set or other equip- ment so that it can operate with the tuner. 3. Set the amplifier, stereo set or other equip- ment to monaural operation. 4. Tune to the station of your choice by means of the TUNIN

41、G knob using the dial and the Tuning Indicator. 5. Use other switches according to your needs. FM MPX STEREO RECEPTION . 1. Set the SELECTOR switch. at MPX. 2. Adjust the amplifier, stereo set or other equip- ment so that it can operate with the tuner. 3. Set the amplifier, stereo set or other equip

42、- ment to stereo operation. 4. Tune to the station of your choice by means of the TUNING knob using the dial and the Tuning Indicator. The moment you are tuned to an FM stereo station, the FM Stereo Indicator lights up. It does not light up in other cases. -9- 5. Use other switches according to your

43、 needs. N.B.-Read the instrU:ctions for the amplifier, stereo set or other equipment before you use it in combination with the tuner. TAPE RECORDING When you use a tape recorder to record broad- casts, connect it to the tuner as described before. When you want to monitor the recording, connect earph

44、ones to the tuner in the same way. It is better to make recordings through the tuner than through the connected amplifier. HINTS ON USE HOW TO ELIMINATE UNPLEA- SANT RADIO NOISE A) AM BROADCASTS An AM radio noise is often eliminated simply by replacing the antenna. Usually the noise is heard in the

45、area where the station signal is too weak due to topogra- phy, buildings etc. To eliminate it, connect PVC wire to the AM antenna terminal of this tuner and put it up on the wall of your listening room. If the noise is stil heard or the sensitivity of the tuner is stil poor, an outdoor antenna shoul

46、d be installed. A noise may be heard depending time, fre- quency, station etc. To eliminate such a noise, ground the tuner or turn the power plug upside down. B) FM BROADCASTS There are two trouble-sources in the FM radio noises: one is caused by the insu6cient anten- na input and the other is cause

47、d by other electrical appliances placed near the amplifier. The poor antenna input is due to badly in- stalled antenna or remoteness from the station. In the latter case, set the FM sensitivity switch at DISTANT. Change the height and direction of the FM antenna (supplied). If the noise is stil hear

48、d, use an outdoor antenna exclusively for FM reception. Note that an excessively long antenna may rather cause a noise. The sensitivity of the tuner varies depend- ing on the transmitting conditions of the sta- tion. It happens, therefore, that one station signal is well received but the other stati

49、on . signal is il received. C) NOISE COMMON TO FM AND AM BROADCASTS If you live in a closely built-in area, noses may be caused by some outside factors. To eliminate, install a noise arrester with the electrical appliances or the power source of the amplifier. D) FM MPX STEREO When you are tuned to an FM multiplex program, you may notice a