lexicon 300lserv电路图.pdf

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1、300L Digital Effects Processor Service Manual RadioFans.CN 收音机爱 好者资料库 Lexicon This triangle, which appears on your component, alerts you to the presence of uninsulated, dangerous voltage inside the enclosure. voltage that may be sufficient to constitute a risk of shock. CAUTION This triangle, which

2、appears on your component, alerts you to important operating and main- tenance instructions in this ac- companying literature. RISK OF ELECTRIC SHOCK DO NOT OPEN RISK OF ELECTRIC SHOCK DO NOT OPEN This equipment generates and uses radio frequency energy and if not installed and used properly, that i

3、s, in strict accordance with the manufacturers instructions, may cause interference to radio and television reception. It has been type tested and found to comply with the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of FCC Rules, which are desi

4、gnated to provide reasonable protection against such interference in a residential installation. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause interference to radio or television reception, which can be determined by turnin

5、g the equipment OFF and ON, the user is encouraged to try to correct the interference by one or more of the following measures: Reorient the receiving antenna Relocate the computer with respect to the receiver Move the computer away from the receiver Plug the computer into a different outlet so that

6、 the computer and receiver are on different branch circuits. If necessary, the user should consult the dealer or an experienced radio/television technician for additional suggestions. The user may find the following booklet prepared by the Federal Communications Commission helpful: How to identify a

7、nd Resolve Radio/TV Interference Problems. This booklet is available from the U.S. Government Printing Office, Washington, DC 20402, Stock No. 004-000-00345-4. Notice The Lexicon 300L is a rugged device with extensive electronic protection. However, you should observe the same reasonable precautions

8、 that apply to any piece of audio equipment. Always use the correct line voltage. Refer to Chapter 1 of this manual for power requirements. Dont install the unit in an unventilated rack, or directly above heat-producing equipment such as power amplifiers. Maximum ambient operating temperature is 35C

9、 (95F). Never attach audio power amplifier outputs directly to any of the units connectors. Before turning the unit on or off, mute your monitor speakers to avoid possible damage from transients. To prevent fire or shock hazard, do not expose the unit to rain or moisture. Precautions Lexicon Inc. 3

10、Oak Park Bedford, MA 01730 Tel 781-280-0300 Fax 781-280-0499 Copyright 1996 All Rights Reserved. Lexicon Part # 070-11474Printed in the United States of America RadioFans.CN 收音机爱 好者资料库 300L Service Manual 300L Digital Effects Processor Service Manual RadioFans.CN 收音机爱 好者资料库 300L Service Manual Table

11、 of Contents 1.300L Controls and Connectors Mounting. 1-2 Power Requirements . 1-2 Rear Panel. 1-3 Connectors and Cables . 1-4 About the LARC. 1-6 How to Interface the LARC. 1-7 Setting Analog Audio Levels. 1-8 Periodic Maintenance . 1-10 Ordering parts. 1-10 Returning units for service . 1-10 2.Per

12、formance Verification Introduction. 2-2 Initialization and Inspection . 2-3 Power Supply . 2-4 Power Fail. 2-5 Timecode Tests . 2-5 Listening . 2-6 Audio Proof of Performance . 2-7 Level Test Frequency Response Noise THD Crosstalk Power Up Shock DSP Board Troubleshooting. 2-10 Cable Connections . 2-

13、10 Audio Problems . 2-11 One Channel Bad Both Channels Bad No Output No Output with no relay click on power up Effects dont sound the same as when stored The LARC control head will not light Touching a LARC slider resets unit Audio Precision ATE Test Descriptions. 2-13 3.Circuit Description Architec

14、tural Overview. 3-2 Host Board. 3-3 68008 Bus Interface . 3-5 Interrupts . 3-6 Memory. 3-6 The DUART . 3-7 Duart Interrupts DUART Input/Output Ports DUART Input Ports DUART Output Ports Time Code Chip Select. 3-9 Limits of Operation . 3-9 System Clock Generation Circuits. 3-11 Master Clock Clock Sou

15、rce Sample Clocks Phase-Locked Loop. 3-12 The Phase Comparator Loop Filter The VCO Input/Output Audio Level Strobe . 3-13 Z80 DMA Access. 3-14 Digital Interface Board . 3-17 AES/EBU Interface EIAJ CP-340 Interface Time Code Input EMI Considerations DSP Board. 3-18 DSP Slaves - Lexichips . 3-19 Lexic

16、on Z80 Control Processors . 3-19 Z80 DMA Interface Slave Control Status Registers Slave Status Registers . 3-21 Wait State Generation . 3-22 Audio Routing Data . 3-22 Routing Implementation Input Routing Output Routing Lexichip I/O. 3-24 Lexichip Input Lexichip Output Inter-Lexichip Communication Di

17、gital Filter. 3-25 Peak-Detect. 3-26 MIDI . 3-26 Audio RAM Boards . 3-26 Analog Boards . 3-27 Analog I/O Board Analog Motherboard Differential Input Circuitry Programmable Input Gain Circuitry Pre-Emphasis/ Input Offset Servo A/D Conversion D/A Conversion Output Filtering Programmable Output Gain Ci

18、rcuitry Balanced Output Driver Voltage Regulators and Relay Drivers Power Supply Board. 3-30 LARC . 3-31 Power Supply CPU Reset Logic Address Decoding Logic ADC Logic UART Logic RS-422 Logic Litronix Display Logic Buffered Bus and Sink Logic 4.Specifications 5.Parts List 6.Schematics and Assembly Dr

19、awings Controls and Connectors 1 Lexicon Controls and Connectors 1-2 MountingBefore rack-mounting the 300L, you may want to remove the four rubber feet attached to the bottom of the chassis. Gently pry off the black plastic buttons in the center of each foot, then remove the foot itself. The 300L me

20、asures 19W x 3.50H x 13.9D (483 x 90 x 353 mm). It uses two EIA-standard rack spaces and can be mounted on any level surface or in a standard 19 inch (483 mm) rack. Whatever mounting method you use, make sure that the 300L is securely screwed into the rack adapter. If the 300L is mounted in a rack o

21、r road case, support the rear of the chassis to prevent possible damage from mechanical shock and vibration. The 300L is equipped with a 3-pin IEC power connector and detachable cord, providing chassis grounding to the AC mains line. Plug the female end of the power cord into the 300, and the male e

22、nd into a wall outlet. The 300L is internally wired to operate at 100, 120, or 230 VAC. The operating voltage set at the factory is marked on a label attached to the rear panel. Check the label before applying power to the unit. Power Requirements Controls and Connectors 1-3 300L Service Manual OUT

23、MIDI THRUIN DODI DI DO EIAJ CP340 COMM PORT AES/EBUDOTIME CODE IN PUSH DI PUSH R OUTR IN PUSH L OUTL IN PUSH INPUT GAIN MIDI Connectors AC Power Standard 3-pin IEC power connector. Communications Port DE9 LARC connec- tor. Input Gain 2-position (In/Out) switch for matching in- put gain to the source

24、 being used. In = +16dB; Out = 0dB. Out: Transmits MIDI data to other equipment. Thru: Passes any MIDI data received without change. In: Receives MIDI information from other MIDI equipment such as master keyboard controllers, MIDI foot controllers, sequencers and synthesiz- ers. Analog Inputs and Ou

25、tputs Digital Inputs and Outputs Inputs Three connectors are provided for digital input: AES/EBU professional format (1): 3-pin female XLR S/PDIF EIAJ CP-340 consumer format (2): unbalanced coaxial RCA optical (fiber-optic) One of these connectors may be selected for digital input. Outputs Output fo

26、rmat can be AES/EBU or S/PDIF. Output always goes to all three digital outputs. Digital interfaces conform to AES 3-1992 (ANSI S4.40-1992). Input/output impedance levels of the AES/EBU connectors comply with the CCITT V.11 EIA RS-422A. Time Code In 3-pin female XLR con- nector for input of SMPTE (Dr

27、op or Non- drop), EBU, or FILM time code formats. (Electronically bal- anced, 100mV p-p minimum) 3-pin XLR connectors, electronically balanced. Either pin 2 or pin 3 can be used as high but, to maintain polarity when transferring data to the digital domain, pin 2 high convention is used by Lexicon.

28、Pin 1 and either pin 2 or pin 3 of each output must be grounded for unbalanced operation. Input impedance is 50k unbalanced, and 100k balanced. Inputs accept input levels from -14dBu to +20dBu. Output impedance is 75, and levels up to +18dBu are possible. The Rear Panel Lexicon Controls and Connecto

29、rs 1-4 SignalMating ConnectorDescription L and R AnalogXLR A3MActive balanced, pin 2 high Audio Input+2dBu min; +20dBu max at 0dB setting L and R AnalogXLR A3FActive balanced; pin 2 high Audio Output-2dBu to +18dBu at full scale output AES/EBUXLR A3MBalanced RS-422 Digital Inputpin 2 high AES/EBUXLR

30、 A3FBalanced RS-422 Digital Outputpin 2 high SPDIFRCAUnbalanced 75 EIAJ CP340 Consumer Digital Input and Output SPDIFSee belowEIAJ Consumer Digital EIAJ CP340Audio format Consumer Digital Audio Optical Input and Output Time CodeXLR A3MActive balanced; pin 2 high Input-12dBm to +8dBm operating range

31、MIDI In5-pin DINStandard MIDI Interface MIDI Out MIDI Thru Pin 2 high by convention. 2 = high 3 = low 1 = ground 1 = ground 3 = low 2 = high Female Male Connectors andCables Connectors Controls and Connectors 1-5 300L Service Manual Below are recommended manufacturers part numbers for cable and cabl

32、e assemblies. In some cases, two types are specified: one with an overall braid shield for heavy use, and one with a foil shield for permanent installation. Analog Audio and Time Code Belden 8412 (microphone cable with braided shield) Belden 9461(foil shield) AES/EBU Belden 9860 (braided shield) Bel

33、den 9271 (foil shield) Maximum recommended length: 100 ft (30M) SPDIF (EIAJ CP340) Consumer Digital Audio Belden 9259 (22 AWG conductor, .242 O.D.) Belden 8218 (27 AWG conductor, .150 O.D.) Maximum recommended length: 32 ft (10M) SPDIF (EIAJ CP340) Consumer Digital Audio Optical Toshiba TOCP174y Son

34、y POC-15 Maximum recomended length: 16 ft (5M) Analog Audio I/O and Time Code AES/EBU Digital Audio I/O SPDIF (EIAJ CP340) Consumer Digital Audio I/O MIDI IN, OUT and THRU For best performance, maintain balanced connections, and use high-quality, low-capacitance, twisted-shielded pair cable. When co

35、nnecting to a single-ended, unbalanced device, connect the low side to signal ground at the unbalanced piece of equipment. For mono connection, connect the left and right input channels in parallel. Be careful to keep input and output to all channels wired consistently. Out-of- phase wiring can prod

36、uce audible effects. This interface requires balanced connections using high-quality, low-capaci- tance, controlled-impedance, data communication, twisted-shielded pair cable. It will not work reliably if microphone cable is used. This interface is unbalanced but, because it carries digital signals,

37、 it requires the use of 75 RG-59 coaxial cable. Use commercially-available, consumer audio optical cable assemblies. Use standard 5-pin DIN MIDI cable assemblies, available from your local dealer. Cables SPDIF (EIAJ CP340) Consumer Digital Audio Optical I/O Lexicon Controls and Connectors 1-6 1 6 2

38、7 3 8 4 9 5 0 PROGREG MUTE ENTER PAGECTRLMACHSTOBANK SETUP VAR -24 18 12606 +12 ovld dB L R About the LARC Main Display Shows names and values for all selections. Headroom Indicator +12 dBm indicates analog or digital clipping. Proper input level is with +12 dB and ovld LEDs unlit. Program Select Press to enter Program mode. Press repeatedly to scroll through presets in a bank. Control Sliders Adjust parameter values. Function Keys Bank scrolls through groups of programs or reg- isters.