Arcam-Alpha7old-tun-sm 电路图 维修手册.pdf

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1、ALPHA 7/8 FM/AM TUNER SERVICE MANUALALPHA 7/8 FM/AM TUNER SERVICE MANUAL Arcam Alpha 7/8 FM/AM Tuner Service Manual Issue 1 Serial Number beginning AT . - (Paul Newton Sept 96) Circuit Description The Alpha 7 and 8 tuners share the same printed circuit board and technical specification but the main

2、functions of the Alpha 8 tuner can also be operated by remote control. Power Supply Mains voltage selection is made by placing a fuse, of appropriate value, in the 115V or 230V position. The single secondary is rectified and regulated and supplies four regulators. Z7 is always powered when the mains

3、 is connected and keeps the preset memory of the microcontroller intact. The high-value capacitor (C84) will keep this data safe, for a limited time, in case of mains power failure. Z5 provides the main 12V supply rail for the RF and audio circuits. This is always connected, except for the supply to

4、 the FM front end, which is disabled by Q2 when the unit is turned off. Z4 powers the LED backlight on the display PCB. Z6 is the 5V digital supply for the microcontroller. FM Tuner & IF The FM aerial input is mixed in the front end FE1 which provides a 10.7MHz IF output. This is filtered and amplif

5、ied by ceramic filters CF1 & CF2 and the circuit based around Q9 & Q10. The LA1266 (Z9) demodulates the IF at pin 1 into an audio output at pin 12. The quadrature coil is a single-tuned device for low-cost and adequate distortion performance. When a station is tuned correctly the On Tune signal goes

6、 low and drives a green LED on the display PCB. This signal is also used by the auto-stop detection and muting circuits. AM Tuner & IF The LA1266 (Z9) contains the AM RF amplifier, oscillator and mixer circuitry. Switching between FM and AM modes is controlled by the FM signal from the microcontroll

7、er which disables the AM circuitry of Z9 and switches the path of the audio signal through Z8. MW/LW switching is performed by the CMOS switches of Z11. This device is controlled by the LW signal. Each band has its own oscillator and aerial tuning coils, tuned via varicap diodes D23 and D24. The 450

8、kHz IF signal is filtered by coil and ceramic filter combination T5. Birdie Filter The Birdie Filter based around Q12 is a three-pole low-pass filter with a cut-off frequency of about 55 kHz. This is designed to reduce co-channel interference in FM Stereo and cut down on irritating birdie noises. St

9、ereo Decoder Stereo decoding is performed by LA3401 (Z8). The 38kHz reference signal is accurately created by ceramic resonator X3 and does not require adjustment. Stereo separation is adjusted for maximum by preset RV1. This IC also contains FM/AM audio switching and muting functions. Audio Filters

10、 & Output The left and right channel audio outputs from Z8 are filtered by the deemphasis network of R1, C1 etc. The correct deemphasis network is selected by means of jumpers on SK6. C2 & C102 (220pF) are selected for 50us and C3 & C103 (560pF) for 75us deemphasis. The final filter, based on Z3, is

11、 a two-pole low-pass circuit with a cut-off frequency of around 20kHz. Also included is a 19kHz notch filter, L1 & C4, that removes most of the residual pilot tone. Muting When the power switch is turned off Q5 is switched off, enabling the mute circuitry of the stereo decoder (Z8) via diode D9. Thi

12、s removes the need for output muting transistors and eliminates switching clicks and pops. At switch-on the mute is enabled while C21 is charged via Z8. In normal use the mute inside Z8 is enabled in three other ways: The AMUTE signal from the microcontroller is active at power-on and for a short ti

13、me when a preset is changed. When the band is changed the output is muted by charging C52. RadioFans.CN 收音机爱 好者资料库 ALPHA 7/8 FM/AM TUNER SERVICE MANUALALPHA 7/8 FM/AM TUNER SERVICE MANUAL The audio output must be muted whenever the tuner is in stereo mode and is also off-tune. This is to eliminate n

14、oise during tuning and is provided by Q8 and the MONO and OFF TUNE control signals. In Mono mode this mute is disabled so that even weak stations can be heard, despite the noise. Microcontroller Control of the Alpha 7/8 tuners is performed by a single microcontroller Z10, LA7230. This also provides

15、keypad input and drives a LCD directly. At power-on a matrix of diodes is scanned to set-up the controller for the correct options: D11 selects FM/AM operation and the correct channel spacing for European operation. D7 selects the correct frequency ranges. D_LW enables Long Wave oparation and is omi

16、tted for markets where this is not applicable. D10 enables the use of Auto tuning as well as manual tuning. D8 allows the Auto-tuning mode to use the IF Count method of searching. Z10 provides control signal outputs for the following functions: MONOTo defeat the stereo decoder AMUTETurns on the mute

17、 circuit when a button is pressed & during tuning. FM, MW & LWOnly one output active low at any one time. Used to switch on specific parts of the RF circuitry as appropriate. The microcontroller includes a Phase-Locked-Loop (PLL) circuit which compares the tuner local oscillator signals with a refer

18、ence frequency. Based on this information and the required tuned frequency the controller varies the tuning voltage to the FM and AM front ends. The tuning voltages (FMVt & AMVt) have to be filtered from the PLL by the circuitry around Z3. There is a filter each for FM and AM. The local oscillator s

19、ignals are input to Z10 by FMIN and AMIN. Display PCB The display PCB holds the keypad, LCD display, LED backlight module and On-Tune indicator. A remote control receiver pcb is included on the Alpha 8 tuner. This consists of the receiver RX1 and the PIC ic Z1 which decodes the incoming remote contr

20、ol codes and activates the appropriate line to operate the selected function. Test PointDescription TP1Unregulated supply 19v DC TP2Audio & RF supply12v DC TP3Backlight supply12v DC TP4Digital Supply5v DC TP5Back up Supply5.6v DC TP6Signal Strength3.2v with 10mV aerial input TP7AM local Oscillator45

21、0KHz above the tuned AM frequency. 0.6V pk-pk Disassembly For Servicing To remove the board within the tuner follow the instructions below. 1.Remove the top cover. 2.Remove the 4 screws holding the front panel to the chassis and release the locating tabs. 3.Unplug the 2 display board flexfoils where

22、 they enter the main pcb. 4.Remove the 2 screws holding the remote receiver pcb in place if it is an Alpha 8 tuner. 5.The front panel can now be pulled off the unit. 6.To remove the display pcb remove the 10 screws holding the board in place. To remove the main pcb remove the 7 pcb securing screws a

23、nd the screw holding the audio output and aerial sockets to the chassis. The main pcb can now be slid out of the case. RadioFans.CN 收音机爱 好者资料库 ALPHA 7/8 FM/AM TUNER SERVICE MANUALALPHA 7/8 FM/AM TUNER SERVICE MANUAL Alpha 7/8 Tuner Parts List Ref. No.DescriptionPart No. BL1LED BACKLIGHTL801ML BL1CON

24、N 20 WAY ELEV SCKT STRIP8K8020 C1PPRO 470P 63V 5% RA2D147N C2PPRO 220P 63V 5% RA2D122 C3PPRO 560P 63V 5% RA2D156 C4PPRO 4N7 63V 5% RA2D247N C5PPRO 680P 63V 5% RA2D168 C6PPRO 680P 63V 5% RA2D168 C7ELST 10U 50V2N610 C8ELST 10U 50V2N610 C9CERD 100P 63V2A110 C10ELST 100U 25V2N710 C12CERD 10N 100V 20%2A3

25、10 C13CERD 10N 100V 20%2A310 C14CERD 10N 100V 20%2A310 C15ELST 100U 25V2N710 C16ELST 10U 50V2N610 C17ELST 1U0 50V2N510 C18ELST 100U 25V2N710 C19PEST 15N 63V 5%2K315 C20ELST 100U 25V2N710 C21ELST 10U 50V2N610 C22ELST 10U 50V2N610 C23ELST 10U 50V2N610 C24ELST 10U 50V2N610 C25ELST 10U 50V2N610 C26PEST

26、47N 63V 5%2K347 C29CERD 10N 100V 20%2A310 C30CERD 10N 100V 20%2A310 C35PEST 470N 63V 5%2K447 C36PEST 470N 63V 5%2K447 C37ELST 100U 25V2N710 C38CERD 10N 100V 20%2A310 C39PCRB 100N 100V 5% RA 5mm2H410 C41PCRB 100N 100V 5% RA 5mm2H410 C42CERD 22P 63V2A022 C44CERD 47N 63V 10%2A347 C45CERD 47N 63V 10%2A3

27、47 C46CERD 47N 63V 10%2A347 C47CERD 47N 63V 10%2A347 C48CERD 47N 63V 10%2A347 C49CERD 47N 63V 10%2A347 Alpha 7/8 Tuner Parts List Ref. No.DescriptionPart No. C50CERD 47N 63V 10%2A347 C51ELST 1U0 50V2N510 C52ELST 1U0 50V2N510 C53ELST 1U0 50V2N510 C54ELST 1U0 50V2N510 C55ELST 1U0 50V2N510 C56PPRO 1N0

28、63V 5% RA2D210 C57PCRB 100N 100V 5% RA 5mm2H410 C58ELST 3M3 25V2N833 C59CERD 1N0 63V2A210 C60CERD 1N0 63V2A210 C61CERD 1N0 63V2A210 C62CERD 1N0 63V2A210 C65CERD 1N0 63V2A210 C66CERD 1N0 63V2A210 C68ELST 100U 25V2N710 C69CERD 100P 63V2A110 C70CERD 100P 63V2A110 C72ELST 100U 25V2N710 C74ELST 100U 25V2

29、N710 C75PPRO 680P 63V 5% RA2D168 C76PPRO 680P 63V 5% RA2D168 C78ELST 100U 25V2N710 C80CERD 33P 63V2A033 C82CERD 33P 63V2A033 C84ELCAP 0F1 5V MEMORY BACKUP2X010 C85CERD 22P 63V2A022 C86PPRO 100P 63V 5% RA2D110N C87PCRB 100N 100V 5% RA 5mm2H410 C88PCRB 100N 100V 5% RA 5mm2H410 C89CERD 220P 63V2A122 C9

30、0CERD 100P 63V2A110 C91CERD 10N 100V 20%2A310 C101PPRO 470P 63V 5% RA2D147N C102PPRO 220P 63V 5% RA2D122 C103PPRO 560P 63V 5% RA2D156 C104PPRO 4N7 63V 5% RA2D247N C105PPRO 680P 63V 5% RA2D168 C106PPRO 680P 63V 5% RA2D168 C107ELST 10U 50V2N610 C108ELST 10U 50V2N610 C109CERD 100P 63V2A110 CF1CER FILT

31、SFE10.7MA8A RED7M001R RadioFans.CN 收音机爱 好者资料库 ALPHA 7/8 FM/AM TUNER SERVICE MANUALALPHA 7/8 FM/AM TUNER SERVICE MANUAL CF2CER FILT SFE10.7MA8A RED7M001R CV2TRIM CAP 10-60pF6T060 CV3TRIM CAP 10-60pF6T060 CV4TRIM CAP 2-20pF6T020 CV5TRIM CAP 2-20pF6T020 D1SSDIODE 1N4148 75V3A4148 D2SSDIODE 1N4148 75V3A

32、4148 D3SSDIODE 1N4148 75V3A4148 D4SSDIODE 1N4148 75V3A4148 D5SSDIODE 1N4148 75V3A4148 D6SSDIODE 1N4148 75V3A4148 D7SSDIODE 1N4148 75V3A4148 D8SSDIODE 1N4148 75V3A4148 D9SSDIODE 1N4148 75V3A4148 D10SSDIODE 1N4148 75V3A4148 D11SSDIODE 1N4148 75V3A4148 D13SSDIODE 1N4148 75V3A4148 D14SSDIODE 1N4148 75V3

33、A4148 D15SSDIODE 1N4148 75V3A4148 D16SSDIODE 1N4148 75V3A4148 D17RECTIFIER 1N4003F 1A 200V3B4003 D18RECTIFIER 1N4003F 1A 200V3B4003 D19RECTIFIER 1N4003F 1A 200V3B4003 D20RECTIFIER 1N4003F 1A 200V3B4003 D21RECTIFIER 1N4003F 1A 200V3B4003 D22RECTIFIER 1N4003F 1A 200V3B4003 D23VARICAP BB2123E212 D24VAR

34、ICAP BB2123E212 DISP1ALPHA 5.2 TUNER LCDE802MC D_LWSSDIODE 1N4148 75V3A4148 F1FUSEHOLDER 20mm PCB8S004 F1INS COVER PCB FUSEHOLDERF022 F1SPARE FUSE 20mm 100mA TC11106 F2FUSEHOLDER 20mm PCB8S004 F2INS COVER PCB FUSEHOLDERF022 F3SPARE FUSE 20mm 100mA TC11106 F3SPARE FUSEHOLDERF062 FE1TUNER HEAD FM TFFJ

35、4EB005 HS1HEATSINK TO220 CLIP 30F007 JP1JUMPER SOCKET 0.18K004 JP2JUMPER SOCKET 0.18K004 L1INDUCTOR VAR 15mH CLNS35-051487E008 L3INDUCTOR VAR 15mH CLNS35-051487E008 L5FM QUAD DET A5PTL805CL L101INDUCTOR VAR 15mH CLNS35-051487E008 L20133UH IND 34-483307D033 Q1TRANS LF SS P BC557B4A557 Q2TRANS LF SS P

36、 BC557B4A557 Q3TRANS LF SS P BC557B4A557 Q4TRANS LF SS N BC547B4A547 Q5TRANS LF SS N BC547B4A547 Q6TRANS LF SS N BC547B4A547 Q7TRANS LF SS N BC547B4A547 Q8TRANS LF SS N BC547B4A547 Q9TRANS LF SS N BC547B4A547 Q10TRANS LF SS N BC547B4A547 Q11TRANS LF SS N BC547B4A547 Q12TRANS LF SS N BC547B4A547 Q13T

37、RANS LF SS N BC547B4A547 Q14TRANS LF SS N BC547B4A547 Q17TRANS LF SS N BC547B4A547 Q18TRANS LF SS N BC547B4A547 Q19TRANS LF SS P BC557B4A557 R1RES MF W4 1% 68K1H368 R2RES MF W4 1% 82K1H382 R3RES MF W4 1% 12K1H312 R4RES MF W4 1% 22K1H322 R5RES MF W4 1% 12K1H312 R6RES MF W4 1% 4K71H247 R7RES MF W4 1%

38、10K1H310 R8RES MF W4 1% 22K1H322 R9RES MF W4 1% 22R1H022 R10RES MF W4 1% 10K1H310 R11RES MF W4 1% 82K1H382 R12RES MF W4 1% 82K1H382 R13RES MF W4 1% 10K1H310 R14RES MF W4 1% 4K71H247 R15RES MF W4 1% 2K71H227 R16RES MF W4 1% 22K1H322 R17RES MF W4 1% 10K1H310 R18RES MF W4 1% 10K1H310 R19RES MF W4 1% 33

39、0R1H133 R20RES MF W4 1% 330R1H133 R21RES MF W4 1% 2K71H227 R22RES MF W4 1% 4K71H247 R23RES MF FU W3 5% 100R NFR251G110 R25RES MF W4 1% 10K1H310 R26RES MF W4 1% 4K71H247 R27RES MF W4 1% 4K71H247 R29RES MF W4 1% 1K51H215 ALPHA 7/8 FM/AM TUNER SERVICE MANUALALPHA 7/8 FM/AM TUNER SERVICE MANUAL R30RES M

40、F W4 1% 4K71H247 R31RES MF W4 1% 4K71H247 R32RES MF W4 1% 4K71H247 R33RES MF W4 1% 4K71H247 R34RES MF W4 1% 4K71H247 R35RES MF W4 100K 1%1H410 R36RES MF W4 1% 4K71H247 R37RES MF W4 1% 4K71H247 R38RES MF W4 1% 4K71H247 R39RES MF W4 1% 4K71H247 R40RES MF W4 220K 1%1H422 R41RES MF W4 1% 5K61H256 R43RES

41、 MF W4 1% 10K1H310 R44RES MF W4 1% 68K1H368 R45RES MF FU W3 5% 10R NFR251G010 R46RES MF FU W3 5% 10R NFR251G010 R47RES MF FU W3 5% 10R NFR251G010 R49RES MF W4 1% 22K1H322 R50RES MF W4 1% 10K1H310 R52RES MF W4 1% 22R1H022 R55RES MF W4 1% 22K1H322 R62RES MF W4 1% 10K1H310 R65RES MF W4 1% 10K1H310 R66R

42、ES MF W4 1% 18K1H318 R67RES MF W4 1% 39K1H339 R68RES MF W4 1% 4K71H247 R69RES MF W4 1% 3K31H233 R70RES MF W4 1% 1K51H215 R71RES MF W4 1% 2K71H227 R72RES MF W4 1% 330R1H133 R73RES MF W4 1% 100R1H110 R74RES MF W4 1% 1K01H210 R75RES MF W4 1% 2K71H227 R76RES MF W4 1% 330R1H133 R77RES MF W4 1% 15K1H315 R

43、78RES MF W4 1% 22K1H322 R79RES MF W4 1% 5K11H251 R80RES MF W4 1% 1K01H210 R81RES MF W4 1% 2K71H227 R83RES MF W4 1% 10K1H310 R85RES MF W4 1% 22K1H322 R86RES MF W4 1% 10K1H310 R87RES MF W4 1% 4K71H247 R88RES MF W4 1% 10K1H310 R89RES MF W4 1% 2K71H227 R90RES MF W4 1% 2K71H227 R91RES MF W4 1% 10K1H310 R

44、92RES MF W4 1% 4K71H247 R93RES MF W4 1% 220R1H122 R94RES MF W4 1% 4K71H247 R101RES MF W4 1% 68K1H368 R102RES MF W4 1% 82K1H382 R103RES MF W4 1% 12K1H312 R104RES MF W4 1% 22K1H322 R105RES MF W4 1% 12K1H312 R106RES MF W4 1% 4K71H247 R107RES MF W4 1% 10K1H310 R108RES MF W4 1% 22K1H322 R109RES MF W4 1%

45、22R1H022 R201RES MF W4 1% 470R1H147 R202RES MF W4 1% 220R1H122 R203RES MF W4 1% 220R1H122 R204RES MF W4 1% 220R1H122 R205RES MF W4 1% 1K01H210 R206RES MF W4 1% 1K01H210 R207RES MF W4 1% 1K01H210 R208RES MF W4 1% 1K01H210 R209RES MF W4 1% 1K01H210 R210RES MF W4 1% 1K01H210 R211RES MF W4 1% 1K01H210 R

46、212RES MF W4 1% 1K01H210 R213RES MF W4 1% 1K01H210 R214RES MF W4 1% 1K01H210 R215RES MF W4 1% 1K01H210 R216RES MF W4 1% 1K01H210 RV1PRES 100K LIN HORIZ6F410 SK122-WAY FFC CONN8K8022 SK222-WAY FFC CONN8K8022 SK322-WAY FFC CONN8K8022 SK4PHONO SKT 4-WAY EMC8D224 SK5IEC MAINS 2-PIN PCB8A014 SK66-WAY VER

47、T DIL PIN HEADER8K6306 SK7COAX PCB SKT & TWIN CLIPS8H115 SK20122-WAY FFC CONN HORIZ8K8122 SK20222-WAY FFC CONN HORIZ8K8122 SW1SW PUSH 2PCOA1008 SW201SW TACT SINGLE POLE 2-PINA1504 SW202SW TACT SINGLE POLE 2-PINA1504 SW203SW TACT SINGLE POLE 2-PINA1504 SW204SW TACT SINGLE POLE 2-PINA1504 ALPHA 7/8 FM

48、/AM TUNER SERVICE MANUALALPHA 7/8 FM/AM TUNER SERVICE MANUAL SW205SW TACT SINGLE POLE 2-PINA1504 SW206SW TACT SINGLE POLE 2-PINA1504 SW207SW TACT SINGLE POLE 2-PINA1504 SW208SW TACT SINGLE POLE 2-PINA1504 SW209SW TACT SINGLE POLE 2-PINA1504 SW210SW TACT SINGLE POLE 2-PINA1504 SW211SW TACT SINGLE POL

49、E 2-PINA1504 SW212SW TACT SINGLE POLE 2-PINA1504 SW213SW TACT SINGLE POLE 2-PINA1504 SW214SW TACT SINGLE POLE 2-PINA1504 T1ALPHA 5.2 TUNER MAINS TRANSFORMERL807TX T2MW AERIAL COIL A5PTL801CL T3LW OSC COIL A5PTL804CL T4MW OSC COIL A5PTL803CL T5FILTER CERAMIC AM IF7M008 T6LW AERIAL COIL A5PTL802CL X1CRYSTAL 4.500MHz PARALLEL7X017 X3CER RESON CSB456 456kHz7W003 Z3IC OPAMP DUAL NJM2114D5B2114 Z4IC VREG POS 78125D7812 Z5IC VREG POS 78125D7812 Z6IC VREG POS 78055D7805 Z7IC VREG POS 78055D7805 Z8IC RADIO LA34015C3401 Z9IC RADIO LA12665C1266 Z10IC TUNER LC72305C7230 Z11IC CMOS HEF4066BP5F406