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1、RadioFans.CN 收音机爱 好者资料库 - TABLE OF CONTENTS SECTION PAGE Introduction . 1 Service Notes . 1 AM Tuner . 1 FM Tuner . 2 Phono and Pre-Amplifier . ;. 4 Power Amplifier . 5 Power Supply Unit . 5 Audio Trouble Analysis . 5 Test Equipment Required for Servicing . 6 AM Alignment Procedure . 6 FM Alignment
2、Procedure. 7 Audio Adjustment . . . . . . . . . . . 8 Automatic Voltage Regulator Adjustment . 8 Parts List . . . . . . . . . . . . . . . . . 21 -34 Technical Specifications . 34 -35 LIST OF ILLUSTRATIONS FIGURE NO. PAGE 1. Dial Stringing . 8 2. Front Panel Adjustment and Component Locations . 9 3.
3、Main Chassis Component Locations (Top View) . 9 4. Rear Panel Adjustment and Component Locations . 10 5. Main Chassis Component Locations (Bottom View) . 10 6. FM Front End Assembly P100 Component Locations . 11 7. AM Tuner Assembly P150 Component Locations . 11 8. FM IF Amplifier Assembly P200 Comp
4、onent Locations . 12 9. MPX Stereo Decoding Amplifier Assembly P300 Component Locations . 13 10. Pre, Tone Amplifier Assembly P400 Component Locations . 13 11. Noise and DC Amplifier P470 Component Locations . 14 12. Vari-Matrix Unit Assembly P500 Component Locations . 15 13. Loudness, Hi-Filter and
5、 Speaker Switch Unit Assembly P550 Component Locations . 15 14. Temperature Compensation Unit Assembly P580 Component Locations . 15 15. Power Amplifier Assembly P600 Component Locations . 16 16. Phono Amplifier Assembly P700 Component Locations . 17 17. Tone Control Unit Assembly P750 Component Loc
6、ations . 17 18. Power Supply Unit Assembly P800 Component Locations . , . 18 19. AC Rectifier Assembly P850 Component Locations . 18 20. Balance Control Unit Assembly P900 Component Locations . 18 21. Schematic Diagram . . . . . . . 19 -20 RadioFans.CN 收音机爱 好者资料库 INTRODUCTION This service manual was
7、 prepared for use by Authorized Warranty Stations and contains service information for Marantz Model 4430 Quadradial 4 RE!ceiver. Servicing information and voltage data included in this manual are intended for use by the knowledgeable and experienced technician only. All instruction should be read c
8、arefully. No attempt should be made to proceed without a good understanding of the operation in the receiver. The parts list furnish information by which replacement part may be ordered from the Marantz Company. A simple description is included for parts which can be usually be obtained through loca
9、l suppliers. 1. SERVICE NOTES As can be seen from the circuit diagram, the chassis of Model 4430 consists of following units. Each unit mounted on a printed circuit board is described within the square enclosed by a bold dotted line on the circuit diagram. 1. FM Front End . . . . . . . . . . . . . .
10、 . . . . . . . . . . . . . . . . . mounted on P. W. Board, P100 2. AM Tuner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P150 3. FM IF Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P200 4. MPX Stereo Decoding
11、Amplifier . . . . . . . . . . . . . . . . . mounted on P. W. Board, P300 5. Pre, Tone Amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P400 6. Noise and DC Amplifier . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P470 7. Vari-Matrix . . . .
12、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P500 8. Loudness, Hi-Filter and Speaker Switch Unit . . . . . . . mounted on P. W. Board, P550 9. Temparature Compensation . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P580 10. Power Amplifier . .
13、. . . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P600 11. Phono Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P700 12. Tone Control Unit . mounted on P. W. Board, P750 13. Power Supply . . . . . . . . . . . . . . . . . . . .
14、. . . . . . . . . . . mounted on P. W. Board, P800 14. AC Rectifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P850 15. Balance Control Unit . . . . . . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P900 16. Indicator Lamps . . . . . . . . .
15、 . . . . . . . . . . . . . . . . . . . . mounted on P. W. Board, P950 2. AM TUNER All components except tuning capacitor and ferrite bar antenna are mounted on a printed circuit board P150. The AM signals induced in a ferrite bar antenna are applied to the base of RF amplifier transistor H151 throug
16、h a capacitor of C151 and amplified to the level required for overcoming the conversion noises, thus giving good SIN performance. The tuned circuits inserted in both out and input circuit of the RF amplifier assure very high image and spurious rejection per- formance. Thus amplified and selected AM
17、signals are then applied to the base of converter transistor H152 through a coupling capacitor C156. While the local oscillator voltage is injected to the emitter of H 152 through a capacitor C157, both AM signals and oscillating voltage are mixed at the base-emitter junction and converted into 455K
18、Hz intermediate frequency. The resulting IF signal is applied to the first IF transformer L 153 consisting of one ceramic filter and two tuned circuits. The output of L153 is led to the transistor H 153 which in turn apply its output to the transistor of next stage H154. The fully amplified IF outpu
19、t is then applied to the diode H157 to detect audible signal through the detector transformer L154. The detected audio signal is filtered and amplified and the final audio output is obtained from the collector of H 155 and applied to the TAPE OUT jacks and the function switch. The DC component of th
20、e detected IF signal is used as a AGC voltage to control emitter RadioFans.CN 收音机爱 好者资料库 2 - current of H 153 which in turn control the bias current of the RF amplifier through the resistor R179 and R151. A part of IF signal output is also applied to the diode H158 through a capacitor C167 and recti
21、fied to obtain DC current for energizing the AM signal strength meter M010. 2.1 Suggestions for AM Tuner Trouble Shooting Check for broken AM bar antenna, next try to tune station by rotating fly-wheel tuning knob slowly and observe the AM signal strength meter whether it deflects or not. If the sig
22、nal strength meter gives a deflection at several frequencies received, no failure may exist in the stages at least preceding final IF transformer L154. Next connect a oscilloscope to the pin terminal J162 or J 157 and check for audio signals with the tuning meter deflected. If the signal strength me
23、ter does not deflect, check the local oscillator circuit. Normal oscillating voltage at the hot end of the oscillator tuning capacitor is about 2 or 3 volts, varying with tuning capacitor position. When measuring oscillating voltage use a RF VTVM, no circuit tester gives correct indication. If the l
24、ocal oscillator voltage is normal, check all voltage distribution in the AM circuits by using a DC VTVM and compare the measured values with those given in the schematic diagram. 3. FM TUNER The FM Tuner section of Model 4430 is divided into four functional blocks: FM Front End, IF Amplifier and Det
25、ector, Muting Control and MPX Stereo Decoding Circuit. FM signals in- duced by a FM antenna are led to FM antenna coil L101 through ATTENUATOR switch and a balun coil. These signals are then applied to the FET RF amplifier which in turn applies its output to the next FET Mixer H102 through the doubl
26、e tuned high selective circuits. The FET Mixer convert its input signal into 10.7MHz intermediate frequency and amplifies it at the same time. The H 103 is a local oscillator and its output is injected into the source of the FET Mixer, the injection voltage is about 700mV. The 10.7MHz front end outp
27、ut is led to the next IF amplifier unit through a coaxial cable. The IF amplifier unit consists of five stages of IF amplifier and one stage of AGC amplifier. Three pieces of dual elements ceramic filters are also used to obtain high selectivity, four stages of symmetrical diode limiters are also em
28、ployed for the best limiting characteristics, improved capture ratio and good AM suppression. A part of FM Front End output is applied to the AGC amplifier H201 and rectified its output is fed back to the gate of FET RF amplifier to decrease the gain with increased signal strength. The IF signal suf
29、ficiently amplified through every stage of IF amplifier is finally applied to the transistor limiter. The detected audio output is led to the buffer amplifier H208 and its buffer- ed output is led to; (a) noise amplifier H471 through resistor R471 and capacitor C471, (b) OUADRADIAL jack on the rear
30、panel through resistor R484, (c) MPX stereo decoding circuit through R483. 3.1 Audio Muting and Stereo Mode Auto-Selecting Circuit The muting circuit consisting of all solid-state electrical switching has been incorporated in the Model 4430. Three inputs control the muting function. The first is rel
31、ated to singal strength, the second to the noise condition at the detector and the third is derived from the DC com- ponent of the detector output. These inputs are properly matrixed and gated to provide muting free from noise and transients. The first input of DC voltage obtained by rectifying a pa
32、rt of IF output signal from the H206 is applied to the base of H306 and turns on it, if the IF output is greater than predetermined level (muting threshold level). When the H306 is turned on the H307 is turned off, allowing the emitter-collector resistance increasing and the collector voltage rises
33、about 9V. The increased collector voltage increases the gate bias voltage and turns on the switching FET H308, decreasing the source-drain resistance to near zero ohm and allowing the audio signal applied to the source to flow to the center of 38KHz switching transformer through the source-drain pat
34、h. When the input signal is lower than predetermined level, the DC output obtained is small and can not turn on the H306, thus the H306 keeps its turn-off stage and this makes H307 turn on, decreasing the collector voltage and turning off H308. Thus no audio signals can pass through the F ET. This i
35、s the fundamental principle of the muting operation but for more elaborate mut- ing operation the second and the third inputs are necessary. The second input is used to protect the muting operation and MPX stereo beacon lamps from misoperation due to undesirable noises. The high frequency noises inc
36、luded in the detected audio signals are separated by a small capacitor C471 and amplified by the noise amplifier tran- sistor H471 and its output is rectified by the two diodes. The rectified DC output is proportional to the noise components in the audio signals. When there are excessive noises in t
37、he audio signals such as obtained with a station incorrectly tuned in, the rectified DC output turns on the transistor H472, decreasing the emitter-collector resistance to zero. This means the collector of H307 is short-circuited to the ground, therefore the H308 is turned off and any audio signals
38、having excessive high frequency noises can not go through the FETs source-drain path. The transistor H303 connected in series with the 19KHz pilot signal amplifier transistor H302 is also turned off (when the transistor H472 or H307 are turned on.) and no current flows in the H302, resulting in turn
39、ing off the stereo beacon lamps. Thus misoperation due to undesirable noises is also avoided. The third input is obtained from the FM discriminator circuit. The DC output so called S curve is applied to the gate of H478 through a resistor R273 and dividing network (R485 the input right and left chan
40、nel signals are fed directly to the LF and RF channels, while the signals to the LR and RR channels are synthesized from the 2-channel input signals under the control of the dimension control. The LR and RR channel signal components are controlled by the dimension control as shown below. Dimension C
41、ontrol Setting LR Output RR Output Minimum (FCCW) LF +RF RF+ LF Center LF RF Maximum (FCW) j_ LF-RF RF-LF When the dimension control is set to the minimum position the LR and RR channel signals - become monophonic, to the center are stereophonic, and to the maximum are out of phase, thus providing vanished sound image positioning. In the _SQ DECODER position, signal sources
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