Alesis-QuadraVerbPlus-ep-sm维修电路原理图.pdf

Alesis QuadraVerb Service Manual- 1 Alesis QuadraVerb Service Manual Revision 1.00 6/28/94 RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- 2 PREFACE This document is intended to assist the service technician in the operation, maintenance and repair of the QuadraVerb digital effects processor. Together with the QuadraVerb Reference Manual, this document provides a complete description of the functionality and serviceability of the QuadraVerb. Any comments or suggestions you may have pertaining to the document are welcome and encouraged. READ THIS! In addition to any purchase price that Alesis may charge as consideration for Alesis selling or otherwise transferring this service manual (“Manual”) to you, if you are not a service and repair facility (“Service Center”) authorized by Alesis in writing to be an authorized Service Center, Alesis sells or transfers the Manual to you on the following terms and conditions: Only Service Centers authorized by Alesis in writing are authorized to perform service and repairs covered by an Alesis warranty (if any), and transfer of the Manual to you does not authorize you to be an authorized Service Center. Therefore, if you perform, or if the Manual is used to perform, any service or repairs on any Alesis product or part thereof, any and all warranties of Alesis as to that product and any service contract with Alesis for that product shall be voided and shall no longer apply for such product, even if your services or repairs were done in accordance with the Manual. All service or repairs done by you or with reference to the Manual shall be solely your responsibility, and Alesis shall have no liability for any such repairs or service work. All such service or repairs are performed at the sole risk of the person performing the service or repairs. You agree that all such work will be performed in a competent, professional and safe manner at all times and to indemnify and fully hold Alesis and its successors and assigns harmless in the event of any failure to so perform. Your purchase of the Manual shall be for your own ultimate use and shall not be for purposes of resale or other transfer. As the owner of the copyright to the Manual, Alesis does not give you the right to copy the Manual, and you agree not to copy the Manual without the written authorization of Alesis. Alesis has no obligation to provide to you any correction of, or supplement to, the Manual, or any new or superseding version thereof. Alesis shall have the right to refuse to sell or otherwise transfer repair parts or materials to you in its sole discretion. You shall not use, sell or otherwise transfer spare or replacement parts supplied by Alesis to you (i) to repair or be used in products manufactured for or by third parties or (ii) to any third parties for any purpose. You shall not make any warranties or guarantees with respect to the products of Alesis or the use thereof on behalf of Alesis or in your own name. The foregoing describes the entire understanding related to sale or transfer of the Manual to you, and no other terms shall apply unless in a writing signed by an authorized representative of Alesis. RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- 3 WARNINGS TO REDUCE THE RISK OF ELECTRIC SHOCK OR FIRE, DO NOT EXPOSE THIS PRODUCT TO WATER OR MOISTURE. CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN The arrowhead symbol on a lightning flash inside a triangle is intended to alert the user to the presence of un-insulated dangerous voltage within the enclosed product which may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point inside a triangle is intended to alert the user to the presence of important operating, maintenance and servicing instructions in the literature which accompanies the product. CAUTION Danger of explosion if battery is incorrectly replaced. Replace only with the same type or equivalent type recommended by the equipment manufacturer. Battery Manufacturer: Tadiran Type: TL-5101 Rating 3.6V REPAIR BY ANY PERSON OR ENTITY OTHER THAN AN AUTHORIZED ALESIS SERVICE CENTER WILL VOID THE ALESIS WARRANTY. PROVISION OF THIS MANUAL DOES NOT AUTHORIZE THE RECIPIENT TO COMPETE WITH ANY ALESIS DISTRIBUTOR OR AUTHORIZED REPAIR SERVICE CENTER IN THE PROVISION OF REPAIR SERVICES OR TO BE OR MAKE REPAIRS AS AN AUTHORIZED SERVICE CENTER. ALL REPAIRS DONE BY ANY ENTITY OTHER THAN AN AUTHORIZED ALESIS SERVICE CENTER SHALL BE SOLELY THE RESPONSIBILITY OF THAT ENTITY, AND ALESIS SHALL HAVE NO LIABILITY TO THAT ENTITY OR TO ANY OTHER PARTY FOR ANY REPAIRS BY THAT ENTITY. RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- 4 SAFETY SUGGESTIONS Carefully read the applicable items of the operating instructions and these safety suggestions before using this product. Use extra care to follow the warnings written on the product itself and in the operating instructions. Keep the operating instructions and safety suggestions for reference in the future. 1. Power Source. The product should only be connected to a power supply which is described either in the operating instructions or in markings on the product. 2. Power Cord Protection. AC power supply cords should be placed such that no one is likely to step on the cords and such that nothing will be placed on or against them. 3. Grounding the Plug. This product has a 3-wire grounding type of plug (a plug with a grounding pin) for safety purposes. This plug can only be used in a grounding power outlet. If the plug does not insert into the outlet you are using, the outlet probably is not a grounding type of power outlet. Contact your electrician to replace the obsolete outlet with a grounding type of outlet instead of defeating the safety feature of the grounding type of plug. 4. Periods of Non-use. If the product is not used for any significant period of time, the products AC power supply cord should be unplugged from the AC outlet. 5. Foreign Objects and Liquids. Take care not to allow liquids to spill or objects to fall into any openings of the product. 6. Water or Moisture. The product should not be used near any water or in moisture. 7. Heat. Do not place the product near heat sources such as stoves, heat registers, radiators or other heat producing equipment. 8. Ventilation. When installing the product, make sure that the product has adequate ventilation. Improperly ventilating the product may cause overheating, which may damage the product. 9. Mounting. The product should only be used with a rack which the manufacturer recommends. The combination of the product and rack should be moved carefully. Quick movements, excessive force or uneven surfaces may overturn the combination which may damage the product and rack combination. 10. Cleaning. The product should only be cleaned as the manufacturer recommends. 11. Service. The user should only attempt the limited service or upkeep specifically described in the operating instructions for the user. For any other service required, the product should be taken to an authorized service center as described in the operating instructions. 12. Damage to the Product. Qualified service personnel should service the unit in certain situations including without limitation when: a. Liquid has spilled or objects have fallen into the product, b. The product is exposed to water or excessive moisture, c. The AC power supply plug or cord is damaged, d. The product shows an inappropriate change in performance or does not operate normally, or e. The enclosure of the product has been damaged. RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- 5 General Troubleshooting While this manual assumes that the reader has a fundamental understanding of electronics and basic troubleshooting techniques, a review of some of the techniques used by our staff may help. 1. Visual Inspection - A short visual inspection of the unit under test will often yield results without the need of complex signal analysis (burnt, or loose components are a dead giveaway). 2. Self Test - Alesis products that utilize microprocessor control contain built in test software which exercises many of the units primary circuit functions. Self test should always be done following any repair to ensure basic functionality. 3. Environmental Testing - Applying heat and cold (heat gun/freeze spray) will often reveal thermally intermittent components (Clock crystals, I.C.s, and capacitors are particularly prone to this type of failure). 4. Burn in Testing - Leaving a unit running overnight often reveals intermittent failures such as capacitors that begin to leak excess current after a significant amount of time. 5. Cable Checks - Wiggling cables can reveal intermittent failures such as loose cables or poorly soldered headers. Remember to check power supply cables as well. 6. Flexing the PC Board - Poor solder joints and broken traces can often be found by pressing the PC Board in various places. 7. Tapping Componants - Somtimes tapping on a component (particularly crystals) will cause it to fail. 8. Power Down/up - Turning the unit off and back on rapidly several times may reveal odd reset and/or power supply failures. 9. Reset Threshold - A Variac (variable transformer) can be used to check reset threshold levels. This can be particularly useful in helping customers with low line problems. 10. Compressors - Using a compressor/limiter is often helpful when attempting to solve low level noise problems, as well as assisting with DAC adjustments. 11. Sweep Tests - Sweep generators are very useful in checking the frequency response envelopes of anti-aliasing filters. 12. Piggybacking - Piggybacking I.C.s is particularly useful when troubleshooting large sections of logic. This is especially true when working with older units. RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- 6 Table of Contents PREFACE . ii READ THIS! . ii WARNINGS . iii SAFETY SUGGESTIONS . iv General Troubleshooting . v 1.0 QuadraVerb General Description . 1 2.0 Power Supply . 1 2.1 Battery Backup . 2 3.0 Analog Signal Paths . 2 3.1 Anti-Aliasing Filters . 3 3.2 Successive Approximation . 3 4.0 Digital Signal Paths . 4 4.1 80C31 Micro Controller Circuit . 4 4.2 Reset . 4 4.3 Memory Mapped I/O . 5 4.4 Analog Input and the 8031 . 5 4.5 DASP 24 ASIC . 5 5.0 Test Procedures . 6 6.0 Adjustments. 6 7.0 Updates and Revisions . 6 7.1 D15 . 7 7.2 Header Capacitor . 7 7.3 R66 . 7 7.4 SRAM Supply . 7 7.5 Battery Ground . 7 7.6 Cables . 7 7.5 LCD Contrast . 7 7.6 LCD Cable Header . 7 7.7 Wet VCA Removal . 7 7.8 DAC Adjustment Installation. 8 7.9 Increasing Output Gain . 8 7.10 QV I/P Filter Kit Installation . 8 8.0 Helpful Hints & Common Solutions . 12 9.0 Schematics . 14 10.0 Software History . 16 11.0 Quadraverb Plus MIDI Implementation/System Exclusive . 18 12.0 Quadraverb Service Parts List . 34 Index . 37 Service Manual History . 39 RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- 1.0 QuadraVerb General Description The QuadraVerb, and other digital reverbs, achieve their results by slicing analog signals into segments, and then converting them to a numeric value, corresponding to the amplitude of the signal at that particular instant. These values are then mathematically manipulated, and stored at various locations in a memory loop for eventual playback. By varying the placement and amplitude of incoming samples, discrete time delays are achieved. When mixed together, and converted back into analog, these delays simulate the reflections associated with natural reverbs, and delays, as well as non natural effects such as reverse reverbs, and gated reverbs. The added capabilities of an 80C31 micro controller allow for user manipulation and storage of algorithm parameters, as well as effects such as chorus, and flange, that require real-time manipulation of algorithms. Please note that there are several different main PCB revisions, so differences will be noticed from unit to unit. 2.0 Power Supply The power supply begins with the 9 Volt A.C., adapter. Input from J6 is R.F. filtered by C31 before on/off switch S1. From there it is split for the +12V, -12V, and +5V rails. The +12V rail consists of a voltage doubler (C22, C24, and D13, D14), a 7812 regulator (U31), and filter caps (C3, C14). The -12V rail is a mirror of the +12V rail, consisting of voltage doubler (C21, C23, and D10, D11), a 7912 regulator, and filter capacitors (C7, and C15). The +5V rail consists of a rectifier diode (D12), filter capacitors (C17-C20), a 7805 regulator, and a multitude of 0.1uF bypass capacitors. Note that the raw +10V line used by the microprocessor reset, and the SRAM power supply (when retrofitted), and is located at the input to the 7805 regulator. 2.1 Battery Backup Diagram 1 RadioFans.CN 收音机爱 好者资料库Alesis QuadraVerb Service Manual- Battery backup is actually more complicated than it might first appear, as it depends on a good system reset (see section 4.2 for details) in order to function properly. The actual backup circuit consists of a battery (3V - 3.6V Lithium), a 10K resistor (R61) for checking standby current (see below), a steering diode (D4), a filter capacitor (C16), and a transistor/resistor/diode combination that acts as a steering diode. This combination may be missing on older board revisions, and must be installed (see section 7.0) to prevent data corruption due to a significant difference between Vcc, and the amplitude of the data buss. SRAM standby current should always be checked. While the unit is off, check the voltage across R61. If the voltage is higher than 80mV (specification, although a 1 to 20mV range is more normal) then a problem exists. Usually it indicates a bad (or simply wrong) SRAM, or a short, somewhere along the MEM PWR line. Note, that for a short time, Sony 58256-PM (high power) SRAMs were being installed at the factory, and should be replaced with low power versions (58256-LP) when found (see section 7.0.), in order to eliminate excess battery drain. We are currently using Hitachi 62256ALPs as replacements. CAUTION:Danger of explosion if battery is incorrectly replaced. Replace only with the same type or equivalent type recommended by the equipment manufacturer. Battery Manufacturer: Tadiran Type: TL-5101 Rating 3.6V 3.0 Analog Signal Paths The inputs (stereo) have their impedances fixed at 1M by R3 and R6. While operating the unit monauraly (left input only) the input impedance fixed at 500K (R3, and R6, in parallel). From there, the inputs are buffered by U1, A.C. coupled (C1, C2), and passed through a variable (input level), X10, gain stage. The stereo signal is then sent to the outputs via the dry VCA (U5). It is also summed to mono (Via R17, R18) before being passed along to the anti-aliasing filter (discussed later), and the LED control circuit. The LED circuit consists of a rectifier (U4, D2), a fairly standard comparator ladder (U7 & associated resistors), and a one shot multivibrator (U24, D3, etc.) to provide a tim