Alesis 4 Service manual
Contents
1. Description PCB Ref Designator Comment n n ae ASY M4 PROCESSOR MIDIVERB 4 1 ASY 979 0100 ASSY PCB MAIN M4 1 ASY 9 96 1246 ASIC POT 4 CHANNEL DIGITAL M4 TESTED 1 MAIN U6 9 79 0112 ASSY PCB PANEL FRONT M4 1 FP PCB ASSY 4 18 1003 CABLE DIL 12 PIN 90MM 1 M4 1 4 18 1675 CABLE DIL 16 PIN 210MM 1 M F M4 1 4 19 1403 CABLE 3 LEAD 20 STRIPPED amp TINNED 1 F P ENCODER CABLE 4 193417 CABLE 2 PIN SIL 12 2MM 1t 4 19 1418 CABLE 2 PIN SIL 35MM 1 l CAP 1 08 0101 CAP 10 MF ELEC 16V 11 MAIN C1 4 6 7 10 14 15 17 20 1 08 0228 2200 ELEC 16V 1 C5 1 08 0474 47 MF ELEC 16V 4 C8 9 13 16 1 09 0221 220 MF ELEC 25V 4 MAIN C11 12 18 19 DIO 2 01 4003 DIODE POWER 1N4003 5 MAIN D2 6 DIO 2 02 5231 DIODE ZENER 1N5231B 1 MAIN D1 4 14 0012 HEADER 12 PIN DIL XR 1 F P Ji 4 14 0116 HEADER 16 PIN DIL 0 1 SHROUDED 1 42 HDW 5 00 0020 SCREW 3 x 7 PHIL SLOT 9 HDW 5 00 0016 SCREW 6 32 x 1 4 PP ZNC 1 HOLDS REGULATOR 7805 TO PCB l HDW 5 02 6320 NUT KEP 6 32 1 HOLDS REGULATOR 7805 TO PCB IC 2 31 0060 IC SOFTWARE VER 1 03 EPROM M4 1 MAIN U2 IC 227 0032 POT 4 CHANNEL DIGITAL IC 2 11 7805 REG 7805 5V TO220 NATIONA 1 MAIN U3 IC 2 13 7812 _ REG 78L12 12V T2. 5 7Z00 Test PrOGBOdUl BS oet tpud Rei lk Roko ai ete tet 7 310 Self TOS ss mno tand ke d teet oj aL 7 7 20 Further eC AIS E Fi 8 00 Tro bleshoo tirlgzu amp e ad uda do da 8 TAV SES Gg TT TETTE TET TT TET 9 10 00 Software History 02004000000 13 11 00 MIDI 15 OVERVIEW e a eo uapa tna ka ook da 15 THE CHANNEL BY TE a Tala a 15 THE OPGODE BY TE Ss S d deca de M OO o ae ce 15 SYSTEM INFO 16 PROGRAM TABLE DATA ra 17 EDIT BUFFER DATA 17 ALL USER PROGRAMS DAT ncn rin 17 SINGLE PROGRAM DATA 17 STORE PROGRAM DATA ii i 17 NOTES mE 17 12 00 Service Parts LIS sss san oka 18 13 00 Service Manual 20 INDEX os eS M SM te NAE Led ed 21 Alesis MidiVerb IV Service Manual vi 03 05 99 1 00 General Description The MidiVerb IV is continuation of the Alesis line of quality studio signal processors As is the tradition at Alesis much of units complex functions are incorporated into an LSI ASIC reducing parts count and cost as well as increasing reliability and serviceability The MidiVerb IV pushes the concept
3. 99 A188 q48AIpIII SIS V VAJN x 9 Ll 8919S Al H AIPIN SIS IV 66 40 60 mu mmm i z be E E 8 V A y m m m 4 E 3 y Y oan x eee 5 eee a o s o 5 853 e siko e e e e n ind e e o e e e e LO 5 7 BATI 2222222 J9 9 7 dj d 3 Q5 0 IS CORP AIN PCB 40 1103 REV 5 19 94 ALI P R C27 09 40 1103 TOPTRACE REV B 03 05 99 12 09 40 1103 BOTTRACE REV B Alesis MidiVerb IV Service Manual 10 00 Software History V1 02 02 17 95 Checksum 1B39 NOTE If you are upgrading from V 1 00 V1 02 will force a hard reset when you first install it 1 e your User Programs will be re initialized A hard reset is necessary because some of the Configurations have changed and are no longer compatible with older versions If you are upgrading from V1 01 V 1 02 will not force a hard reset Fixed a bug which was causing the MIDI Channel to be off by 1 after cycling the power Fixed a problem which caused Pitch Shi
4. 16 03 05 99 PROGRAM TABLE DATA The Program Change Table data consists of 256 transmitted bytes This results in 128 actual bytes since the data is nibblized and transmitted as follows 0000dddd first byte contains high nibble bits 4 7 0000dddd second byte contains low nibble bits 0 3 Values 0 127 correspond to Preset Programs 00 127 values 128 255 correspond to User Programs 00 127 EDIT BUFFER DATA The Edit Buffer data consists of one Program Data Block defined below Program Data Block Reserved Always zero Configuration 0 31 8 Byte Name 16 Parameters nibblized so transmit as 32 bytes ALL USER PROGRAMS DATA The All User Programs data consists of 128 Program Data Blocks defined above SINGLE PROGRAM DATA The Single Program data is defined as follows Program number 0 127 selects User 00 127 Program Data Block STORE PROGRAM DATA This message has no corresponding request and contains a single byte of data It instructs the MidiVerb 4 to store the current contents of the Edit Buffer into a specified User memory location The data byte contains the User Program number 0 127 NOTES When you send MIDI Sysex from the MidiVerb 4 s Util Mode this sends four messages total System Info Program Table Edit Buffer and All User Programs Alesis MidiVerb IV Service Manual 17 03 05 99 12 00 Se rvice Parts List QNTY
5. Note that the data encoder is also scanned in this fashion and not all encoder failures are necessarily caused by a bad encoder 6 20 Display LEDs Should one or more front panel LEDs go bad they should be fairly easy to replace using the disassembly procedure outlined below If all of the LEDs are dead then the 74HC138 U3 is probably bad and should be replaced first Again this component is only accessible by disassembling the front panel 6 30 Disassembly Refer to diagram 1 which shows the locations of the critical elements of the front panel assembly Remove the front panel assembly from the main chassis and unplug the cables at J1 and J2 Detach the 4 metal clips from the extruded case Remove the nylon retaining strip freeing the plastic frame assembly Push the frame to the back of the front panel and it should be free to slide out of the side of the front panel To remove the PCB it will first be necessary to unsolder the ribbon cable connecting data encoder to the front panel PCB There are PCB retaining clips built into the plastic frame Gently push these away from the PCB and lift the PCB away from the frame When all six clips have been loosened the board should be free to remove from the frame To remove the data encoder it is necessary to remove the knob first In order to do this without tearing up the front panel use the holes in the back of the frame to push the knob off with a small screwdriver see diagram 2 Alesi
6. 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 Ales
7. problems Compressors Using a compressor limiter is often helpful when attempting to solve low level noise problems as well as assisting with DAC adjustments Sweep Tests Sweep generators are very useful in checking the frequency response envelopes of anti aliasing filters Piggybacking Piggybacking LC s is particularly useful when troubleshooting large sections of logic This is especially true when working with older units Alesis MidiVerb IV Service Manual V 03 05 99 Table Of Contents PREFACE ii READ A tue Sars ad valet ii WARNING SPA E TTT TTT asya saya iii SAFETY SUGGESTIONS ep etit iv General Troubleshooting ssp E EA d REPRE 1 00 General Description 1 2 00 Power Supply r 1 210 Battery BackUp d quiste 1 3 00 Analog Signal Paths 1 3 TO THDUE eere mee mme mim 1 SEAUS Fi 2 BOO 2 2 e u elem believers 2 5 00 Digital Signal Paths 3 SON izle 3 b 20 MA ASIO iiia na tea M na iain alui ius 3 6 00 The Front Patel iro ER Uere cece deseri nitide 5 6 10 The Keypad anon TK NN KN MA 5 6 20 DisblaV LEDS Es uy stono es eke eo fur A eer dE 5
8. program changes select the Program from the current bank Before they would select only User Programs MIDI Bank Select is now supported Controller 00 Value 0 selects the Preset Bank Controller 00 Value 1 127 selects the User Bank Controller 32 is ignored Tap tempo from footswitch is improved so it doesn t bypass right away Tap tempo from footswitch now changes the Configuration name to lowercase to indicate that the Program has been edited Tap tempo from audio thresholds changed to improve response The MULTI TAP DELAY Configuration now has a MFdbk Master Feedback parameter Mod X is routed to modulate it Now the audio doesn t crackle on program changes Now if you bypass while Dry Defeat is enabled the outputs are muted Preset 00 Bypass now uses a STEREOPITCHSHFT configuration with levels at 0 The old program didnt work when Dry Defeat was enabled Preset 08 TapeEcho changed the delay time to 400mS Renamed User 109 from 90212Chr to 90210Chr Alesis MidiVerb IV Service Manual 13 03 05 99 Renamed User 106 from Model147 to Model122 Now to finish the Switch Encoder Test you press Page A it used to be Input Output V1 00 11 19 94 Checksum 77C8 First Production Release Alesis MidiVerb IV Service Manual 14 03 05 99 11 00 MIDI Implementation System Exclusive Format Software Version 1 02 February 17 1995 OVERVIEW All MidiVerb 4 system exclusive messages have the f
9. to DACDATA Digital Analog Converter DATA 23 24 25 28 42 FROMADC gt FROM Analog Digital Converter SRAMAO 16 gt SRAM Address 0 16 Address buss of the SRAM directly under the control of the M4 ASIC 45 52 59 SRAMD0 7 gt SRAM Data 0 7 Data buss of the SRAM directly under the control of the M4 ASIC XTALIN gt XTAL IN 12MHz crystal oscillator 60 XTALOUT gt XTAL OUT 12MHz crystal oscillator LCDEN gt LCD ENable Enables the LCD s internal data latch Alesis MidiVerb IV Service Manual 03 05 99 6 00 The Front Panel Care should be taken any time that the front panel must be disassembled Some components i e LCD glass and heat seal cable are delicate and will not stand up to a lot of abuse while disassembled It should be noted that while the LCD assembly is accessible at this point field disassembly of the LCD is NOT recommended and front panel repairs in the field should be limited repairing keypad failures The front panel contains three key elements The LCD The Keypad Display LEDs 6 10 The Keypad The 8031 accesses the keypad via a standard row column polling matrix The actual switches are composed of gold plated contact points on the PCB and a carbon coating on the contact points of the rubber keypad The 8031 constantly scans the keypad for button press by sending a low to each row and checking for a corresponding low on any of the columns
10. 15 2 19 R19 2 R20 1 R21 1 19 R26 1 19 R27 1 R34 2 R35 2 R37 2 R38 2 R42 2 19 R43 2 R47 2 R48 2 R49 2 R5 3 19 R51 2 R52 2 R56 2 R60 2 19 03 05 99 R8 3 RAM TEST 7 raw 5V 1 raw supply 3 Read Serial Data 3 reset 1 3 7 13 ROM CHECKSUM 7 RXD 3 5 51 1 sample and hold 2 Sigma Delta 2 SRAM 1 3 4 7 8 19 SRAMAO 16 4 SRAMCE 3 SRAMDO 7 4 Alesis MidiVerb IV Service Manual SRAMWR 4 standby current 1 stereo output 2 SWITCHES ENCODER 7 T Transmit Serial Data 3 TXD 3 U U10 3 19 U12 2 19 U14 3 19 U2 3 18 U6A 1 U6B 1 UZA 2 22 U7B 2 076 2 U7D 2 1 U8B 1 U8C 1 U8D 1 U9 2 3 19 V voltage doubler 1 X XTALIN 4 XTALOUT 4 03 05 99 NOTES Alesis MidiVerb IV Service Manual 23 03 05 99
11. 35 52 SMR 0 10 0102 RES 1K OHM 1 8W 5 1206 11 MAIN R3 4 8 13 14 20 22 24 25 33 36 SMR 0 10 0103 RES 10K OHM 1 8W 596 1206 12 _ R21 29 37 40 45 47 49 63 64 SMR 0 10 0105 RES 1M OHM 1 8W 5 1206 5 MAIN R9 12 27 61 62 SMR 0 10 015 RES 150 OHM 1 8W 596 1206 4 MAIN R42 43 50 51 SMR 0 10 0152 RES 1 5K OHM 1 8W 5 1206 1 MAIN R2 SMR 0 10 0202 RES 2K OHM 1 8W 5 1206 5 MAIN R5 7 10 11 SMR 0 10 0203 RES 20K OHM 1 8W 5 1206 8 MAIN R1 31 32 41 44 66 68 SMR 0 10 022 RES 220 OHM 1 8W 5 1206 6 MAIN R15 19 23 SMR 0 10 0240 RES 24 OHM 1 8W 5 1206 1 MAIN R65 SMR 0 10 047 RES 470 OHM 1 8W 596 1206 7 MAIN R28 53 55 57 59 SMR 0 10 0512 RES 5 1K OHM 1 8W 5 1206 2 MAIN R26 30 SMR 0 11 0153 RES 15K OHM 1 8W 1 1206 1 MAIN R48 SMR 0 10 022 RES 220 OHM 1 8W 596 1206 1 FP R7 SMR 0 10 0622 RES 6 2K OHM 1 8W 5 1206 1 FP 5 SMR 0 10 0682 RES 6 8K OHM 1 8W 5 1206 4 FP R1 4 SMR 0 10 0903 RES 91K OHM 1 8W 5 1206 1 FP R6 SWT 6 02 0002 SWITCH DPDT 1 MAIN SW1 TRN 2 03 4401 TRANS 2N4401 NPN 2 MAIN Q4 Q5 Alesis MidiVerb IV Service Manual 19 03 05 99 13 00 Service Manual History 6 13 95 V1 00 1st Release Alesis MidiVerb IV Service Manual 20 12V 1 5V 1 3 8 18 12V 1 1 12MHz 2 4 2 2N4401 3 3 3 072MHz 2 7 7805 1 18 7812 1 18 7912 1 18 8
12. 8031 3 5 8 21 80C31 3 Ato D 2 adapter 1 ADC 1 8 19 AKM 4318 2 algorithm 3 Analog power 2 anti aliasing 2 ASIC 1 2 3 4 8 18 19 B backup 1 battery iii 1 18 bypass 1 2 8 13 16 bypass filters 2 C C1 2 18 19 C11 1 C12 1 C13 2 C14 2 C16 1 2 C18 1 C19 1 C2 1 C20 1 C24 2 19 C26 2 C3 2 C32 1 C35 1 2 C4 1 C40 2 Alesis MidiVerb IV Service Manual INDEX C41 2 C42 2 C43 2 C44 2 C45 2 C47 2 C48 2 C5 1 C50 2 C8 2 C9 2 D DtoA 2 D10 2 D11 2 19 D2 1 8 18 D3 1 04 1 18 D5 1 D6 1 18 D8 1 DAC 2 4 8 19 DACDATA 4 data buss 3 DATA KNOB 7 DataDisk 7 digital supply 2 digital to analog 2 DigPot 3 8 DigPots 1 2 7 DSPSRAMOE 4 E encoder 5 7 14 18 22 EPROM 3 7 F FROMADO 2 4 front panel 3 5 7 8 19 I I O ports 3 internal DAC reference 2 internal voltage reference 2 J 1 2 18 J2 2 18 J3 1 J4 1 K keypad decoding 3 L LCD 1 3 4 5 7 8 13 21 LCDEN 4 LEDs 7 Lithium 1 18 LRCLK 4 LSADDRO 7 3 4 M M12CLK 4 M3CLK 4 MICROADO 7 3 4 MICROAD12 15 3 MICROALE 3 4 microprocessor 1 3 4 MICRORD 3 MICROWR 3 MIDI 3 7 8 13 15 17 18 MIDI I O 3 7 MIDI TEST 7 MidiVerb IV ii 1 O output filter 2 over sampling 2 P Philips 7360 2 power supply iv 1 7 8 preset data 3 PUPIN 3 PUPOUT 3 R R F 1 R12 1 R
13. Alesis MIDIVERB IV STEREO EFFECTS PROCESSOR Service Manual V 1 00 6 13 95 Alesis MidiVerb IV Service Manual i 03 05 99 PREFACE This document is intended to assist the service technician in the operation maintenance and repair of the MidiVerb IV Stereo Effects Processor Together with the MidiVerb 4 Reference Manual this document provides a complete description of the functionality and serviceability of the Midiverb IV 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 nota 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
14. L 4 1 PLS 9 15 0091 BEZEL DISPLAY M4 1 PLS 9 15 1078 BUTTON POWER Q2 S4 M4 1 PLS 9 15 1117 EXTENDER SWITCH Q2 1 PLS 9 23 1055 KEYPAD RUBBER M4 1 PLS 9 15 0088 BEZEL FRONT PANEL 4 1 RES 0 00 0302 RES OHM 1 8W 5 2 MAIN SMC 1 50 0220 CAP 22 PF NPO 1206 2 MAIN C22 23 SMC 1 50 0270 CAP 27 PF NPO 1206 2 MAIN C40 41 1 50 1500 150 1206 4 MAIN C30 31 37 39 SMC 1 51 0104 0 1 MF X7R 1206 24 MAIN C21 25 27 29 32 36 38 42 45 46 54 1 51 0105 0 01 7 1206 2 MAIN C24 26 SMC 1 51 0104 0 1 MF X7R 1206 1 FP Ci SMI 2 27 0031 ASIC DIG FX M4 1 MAIN U9 SMI 2 67 5168 C 8K x 8 SRAM LH5168N 10L 1 MAIN U10 SMI 2 67 6228 C HM628128LFP 10 SRAM SMD 1 MAIN U11 SMI 2 70 8032 IC 80 31 PQFP SMD 1 MAIN U14 SMI 2 75 4319 C AK4318A DUAL 18 BIT DAC 1 MAIN U12 SMI 2 75 7360 C SAA7360 ADC PQFP 44 SMD 1 MAIN 013 SMI 2 64 7400 C 74HC00 QUAD 2 IN POS NAND GATE 1 MAIN U15 SMI 2 71 0084 IC TLo84 QUAD OPAMP SMD 2 MAIN 07 8 SMI 2 64 0138 IC 74HC138 DEMUX DEC SMD 1 FP U3 SMM 2 50 4148 DIODE SIGNAL 1N4148 SMD 5 MAIN 07 011 SMM 2 51 4401 TRANS 2N4401 NPN SMD 3 MAIN Q1 3 SMM 2 50 4148 DIODE SIGNAL 1N4148 SMD 12 _ FP D9 19 26 SMR 0 10 0047 RES 4 7 OHM 1 8W 5 1206 2 MAIN R56 R60 SMR 0 10 0100 RES 10 OHM 1 8W 5 1206 3 MAIN R34
15. ND ALESIS SHALL HAVE NO LIABILITY TO THAT ENTITY OR TO ANY OTHER PARTY FOR ANY REPAIRS BY THAT ENTITY Alesis MidiVerb IV Service Manual 03 05 99 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 connected to 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 Periods of Non use If the product is not used for any significant period of time the product s AC power supply cord should be unplugged from the AC outlet 4 Foreign Objects and Liquids Take care not to allow liquids to spill or objects to fall into any openings of the product 5 Water or Moisture The product should not be used near any water or in moisture 6 Heat Do not place the product near heat sources such as stoves heat registers radiators or other heat producing equipment 7 Ventilation When installing the product make sure that the product has adequate ventilation Improperly ventilating the product may ca
16. O92 NATION 1 MAIN U4 IC 2 13 7912 REG 79L12 12V TO92 NATION 1 MAIN U5 l IC 2 24 0138 IC 6N138 ISO HEWLETT 1 MAIN U1 JAC 4 02 0001 JACK 1 4 MONO CLIFF 5 MAIN J1 4 7 JAG 4 00 0001 JACK 5 PIN DIN MIDI 2 MAIN J5 J6 JAC 4 16 0002 JACK 3 5MM BARREL P3 1 MAIN J8 LED 3 02 0012 LED T1 HP HLMP1540 5 F P D1 5 LED 3 02 0010 LED HIGH INTENSITY GL3UR8 1 06 LED 3 02 0016 LED BACKLIGHT GRN Q2 6 F P D20 25 LIT 7 51 1031 MANUAL REFERENCE M4 1 LIT 751 1137 CHART USER PROGRAM 4 LIT 7 52 0004 CHART PROGRAM M4 1 7 05 0003 BATTERY 3V LITHIUM PANASONIC 1 MAIN BAT1 ME 7 01 0009 CRYSTAL 12 MHz 1 MAIN 71 MIS 9 00 1011 ENCODER DATA ALPS EC11B 15mm w o SWITCH 1 U8 MIS 9 13 1010 STRIP PE 300MM LG M4 2 MIS 9 23 1014 STRIP FOAM F P 7 x 185mm 4 MIS 9 23 1017 STRIP FOAM SIDE 7 95 04 4 MTL ___9 03 1060 CASE TOP 150MM D4 E Sia MTL 9 03 1105 CASE BOTTOM M4 1 MTL 9 03 1138 PANEL FRONT 4 MTL 9 03 1165 CLIP STRIP RETAINER 4 MTL 9 58 1007 PANEL SIDE RACK EAR 150mm 2 Alesis MidiVerb IV Service Manual 18 03 05 99 Service Parts List continued MTL 9 03 1036 LUG SOLDER 5 MAIN PLS 9 15 0087 KNOB DATA M4 1 9 15 0089 BEZEL FRONT PANE
17. Program 0 127 it is requesting Request Function Dump Message Size Opcode Description in bytes 40 System Info 22 41 Program Table 42 Edit Buffer 50 43 All User Programs 44 Single Program 51 None Store Program 9 SYSTEM INFO DATA Alesis MidiVerb IV Service Manual 15 03 05 99 The System Info data is as follows Input Volume Stereo Input Volume Ch 1 Input Volume Ch 2 Output Volume Stereo Output Volume Ch 1 Output Volume Ch 2 Mod X Mod X Amplitude High Nibble Mod X Amplitude Low Nibble Mod Y Mod Y Amplitude High Nibble Mod Y Amplitude Low Nibble Footswitch Mode System Status Byte Modulator Definitions 0 Pitch Bend 1 Aftertouch 2 Note Number 3 Velocity 4 Controller 0 123 Controller 119 Modulator Amplitude 0 100 0 100 0 100 0 100 0 100 0 100 see Modulator Definitions see Modulator Amplitude see Modulator Definitions see Modulator Amplitude see Footswitch Modes see System Status Byte The modulation amplitude is nibblized with the high nibble being sent first The value is in offset binary so the values 0 to 98 represent amplitudes 99 to 1 the value 99 represents amplitude 00 and the values 100 to 198 represent amplitudes 1 to 99 Footswitch Modes 0 Advance 1 Bypass 2 Controller System Status Byte Thru 0 Off 1 On Omni Bit2 Bypassed Bit3 Cascade Bit4 Comparing Bit5 DONT ALTER Bit6 Edited Bit7 O Alesis MidiVerb IV Service Manual
18. e next test 8 SWITCHES ENCODER Pressing Individual front panel buttons causes their function to be displayed on the LCD Rotating the DATA KNOB causes it s direction to be displayed Power the unit down to exit the self test routines 8 8 7 20 Further Testing A Use a clean audio source CDs preferred and set up the unit according to the user s manual Listen to the wet effects output for any distortion Use the Data Knob to change the input and output levels through their full range to ensure the correct operation of the DigPots To ensure that the shaft encoder is functioning properly all programs should be listened to briefly Turn the input level all the way down and the output level all the up Listen for excessive noise in the noise floor Send and receive all user programs via MIDI to ensure MIDI operation As a final check it s a good idea to physically shake the unit so that no loose parts remain inside the unit 29 9500 Alesis MidiVerb IV Service Manual 7 03 05 99 8 00 Troubleshootinq This chart is presented in the interest of helping technicians new to our product line It is not intended as a substitute for genuine troubleshooting Fe l Observed Problem Possible Cause Possible Solution l I No power unit is DEAD Faulty power supply Replace and retest Faulty 5V rectifier diode D2 Test diode replace if necessary Faulty bypa
19. ess 0 7 Because the 8031 data buss is multiplexed between data and low order addresses a latch must be provided external to hold the low order half of the address during data transfers This latch which was a discreet component in earlier Alesis products has now been incorporated into the M4 ASIC See also MICROALE LSADDRO 7 5 6 MICROAD12 15 MICROprocessor ADdress 12 15 These two address lines from the 8031 are used to decode memory mapped locations such as the LCD enable 7 MICRORD M CROprocessor ReaD enable 8 MICROWR gt M CROprocessor WRite enable Alesis MidiVerb IV Service Manual 3 03 05 99 Pin s Function 10 17 il MICROALE gt MICROprocessor Address Latch Enable Used to enable the low order address buss latch See also MICROADO0 7 LSADDRO 7 LSADDRO 7 gt microprocessor Low order Stored ADDHess 0 7 These lines represent the low order address buss values during the time that the data address bus is transferring data values See also MICROADO 7 MICROALE 43 44 DSPSRAMOE DSP SRAM Output Enable Enables the output of the SRAM directly under the control of the M4 ASIC SRAMWR gt SRAM WRite enable Enables writing to the SRAM directly under the control of the M4 ASIC 19 20 M12CLK gt 12 Mhz CLocK gt 3 Mhz CLocK 21 22 LRCLK gt Left Right CLocK Used to determine which channel of the stereo DAC data is sent
20. fter to be inaccurate when shifting down Also improved the sound quality Because of the above changes some of the Pitch Shifter programs changed slightly Fixed problems with Compare Mode so it behaves consistently Now it works as described in the manual Now entering exiting Compare Mode doesnt cause the audio to crackle Improved MIDI Modulation for the LEZLIESROOM Configuration Added support for the Cascade pixel on the new LCD glass Added an LCD Test In Test Mode to continue after a Test fails you now press Output before it was Input Output V1 01 12 14 94 Checksum 1680 NOTE If you are upgrading from V1 00 V1 01 will force a hard reset when you first install it i e your User Programs will be re initialized A hard reset is necessary because some of the Configurations have changed and are no longer compatible with older versions The REVERSE REVERB Configuration has been renamed to NONLINEAR It is the same as the old Configuration except now it has a Dir Reverb Direction parameter which can be forward or reverse Also the sound quality has been improved somewhat and the range for the Time parameter is longer The Time parameter is now in mSEC rather than generic 0 99 Because of the above changes to the NONLINEAR Configuration all of the reverse reverb Programs have slightly changed Also Preset 28 Shimmer has been changed to ReMiX Now if PChg Util Mode is set to On then incoming MIDI
21. ial Data and TXD Transmit Serial Data ports Front panel keypad decoding and DigPot control are handled through the 8031 s built in I O ports 5 10 RESET The 8031 reset circuit is perhaps the single most important circuit in the M4 When this circuit is functioning incorrectly a complete lock up of the machine will occur On power up the 2N4401 transistor is off the raw supply hasn t raised up far enough yet to bias the transistor on through R5 R8 and the zener divider network The rest of the circuit is contained within the M4 ASIC When the raw supply reaches approximately 7 volts the transistor will turn on causing the reset line to drop low The opposite should occur on power down transistor turns off at 7V threshold reset line goes high during the discharge of the power rails ensuring data integrity 5 20 M4 ASIC A full discussion of this device is beyond the scope of this manual however a brief description of the important pins is necessary and presented below Pin s Function 53 SRAMCE gt SRAM Chip Enable Enable line for 8031 SRAM 55 PUPIN Power UP IN Conditioned raw 5V is used to determine the time at which the unit resets Reset will not occur until the raw supply reaches approximately 7V This is done to ensure that the regulated 5 is steady before machine operation can begin 56 PUPOUT gt Power UP OUT Basically the reset out line 1 4 61 64 MICROADO 7 gt M CROprocessor ADdr
22. is or in your own name The foregoing describes the entire understanding related to sale Alesis MidiVerb IV Service Manual ii 03 05 99 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 Panasonic Matsushita Type BR2325 Rating 3V SmA 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 ANAUTHORIZED SERVICE CENTER ALL REPAIRS DONE BY ANY ENTITY OTHER THAN AN AUTHORIZED ALESIS SERVICE CENTER SHALL BE SOLELY THE RESPONSIBILITY OF THAT ENTITY A
23. ng sent to the output jacks J1 and J2 The output impedance of the unit is fixed at approximately 2200 by resistors R15 and R19 C24 and C26 provide R F filtering for the outputs 4 00 A D D A 4 10 A D The A to D is a 128 times over sampling Philips 7360 high performance device It is o part utilizing high Sigma Delta conversion techniques that eliminates the need for sample and holds and extensive anti aliasing filters The right channel is input through R37 while R47 is a feedback for to the A to D s internal input buffer amplifier R42 and R60 provide negative and positive inputs to the A to D s internal sigma delta modulator C40 is a small filter cap placed between these inputs The left input is identical and uses R38 R49 R43 R38 and C41 C8 C42 C9 and C43 are the bypass filters for the internal voltage reference C35 along with R34 and R35 act as filters for the negative and positive internal DAC reference inputs Analog power is supplied through current limiters R52 and R56 which help suppress current spikes C44 C45 and C13 act as bypass filters for the analog supply The digital supply is filtered by C16 C50 and R60 R48 is a current reference and has a tolerance of 1 for precision The A to D s stereo output is transmitted from the FROMADC line to the M4 ASIC chip U9 4 20 D A The digital to analog converter is U12 which is an AKM 4318A DAC Like the A to D this D to Ais a high performance over sampling ste
24. of integration further than any previous processors adding hardware to the ASIC that was previously discreet components 2 00 Power Supply The M4 power supply begins with the 9 Volt A C adapter Alesis P3 type Input from J8 is R F filtered by C35 before on off switch SW1 From there it is split for the 12V 12V and 5V rails The 12V rail consists of a voltage doubler C11 C18 and D3 D5 a 7812 regulator and a filter capacitor C16 The 12V rail is a mirror of the 12V rail consisting of voltage doubler C12 C19 and D4 D6 a 7912 regulator and a filter capacitor C20 The 5V rail consists of a rectifier diode D2 an input filter capacitor C5 a 7805 regulator an output filter capacitor C10 and a multitude of 0 1uF bypass capacitors Note that the raw 5V line used by the microprocessor reset and the SRAM power supply and is located at the input to the 7805 regulator Likewise the 12 V and 12V raw supply lines are available for use by the LCD 2 10 Battery Backup Battery backup is actually more complicated than it might first appear as it depends on a good system reset see section 5 10 for details in order to function properly The actual backup circuit consists of a battery 3V Lithium a 10K resistor R21 for checking standby current see below a steering diode D8 a filter capacitor C32 and a transistor resistor diode combination that acts as a steering diode while maintaining a high enough
25. ollowing format F0 System Exclusive status 00 00 OE Alesis manufacturer ID 11 MidiVerb 4 ID nn Channel cc Opcode dd Data F7 End of Exclusive THE CHANNEL BYTE For messages originating from the MidiVerb 4 the system exclusive channel will always be the same as the standard MIDI channel and can be adjusted by the user via the global utility functions If the user has enabled Omni mode the MidiVerb 4 will respond to system exclusive messages on ANY channel and transmit on channel 1 Just as it does for ordinary channel messages note controller program change etc when Omni mode is enabled If a transmitting device such as a computer does not know the MIDI channel of a MidiVerb 4 it can use transmit the MIDI universal system exclusive inquiry message with the channel byte set to 7F ALL CALL The MidiVerb 4 will respond with a universal system exclusive identity message with the channel byte set to the current MIDI channel 0 15 This is the recommended technique for closed loop systems as it allows software programs to confirm the MidiVerb 4 s software version and revision while it finds the channel THE OPCODE BYTE Opcodes are divided into two categories Requests and Dumps The values for Request opcodes are closely related to their corresponding Dump opcodes they are simply the Dump opcode with bit 6 set Only one of the Request opcodes has a data byte the Single Program request The data byte specifies which User
26. pair as necessary Faulty or wrong power supply Replace and retest necessary Faulty op amp Troubleshoot and repair as necessary Noisy audio Faulty M4 ASIC Replace and retest Faulty ADC Troubleshoot and repair as necessary Faulty DAC Troubleshoot and repair as necessary I No MIDI in Faulty opto isolator Replace and retest Faulty 8031 Replace and retest MIDI out Faulty 8031 Replace and retest Alesis MidiVerb IV Service Manual 8 03 05 99 9 00 Schematics ERE eb REVISION R ECO NC 4 2 DATE LEF T MONO EZ SWROW2 POTDATA gt cas AUF V ca 1503F R32 20K 1 1 1 RERRRRRRRRRR INPUT RIGHT 42 ve 378 MA io RIGHT J 5 T ALESIS AIN 5 DRAWING NO REV X2 SHEET 1 Alesis MidiVerb IV Service Manual 03 05 99 66 40 60 01
27. pection 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 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 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 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 Cable Checks Wiggling cables can reveal intermittent failures such as loose cables or poorly soldered headers Remember to check power supply cables as well Flexing the PC Board Poor solder joints and broken traces can often be found by pressing the PC Board in various places Tapping Components Sometimes tapping on a component particularly crystals will cause it to fail Power Down up Turning the unit off and back on rapidly several times may reveal odd reset and or power supply failures 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
28. reo device It can achieve an outstanding signal to noise ratio of 98 dB which is unprecedented in it s price range Also the over sampling nature significantly reduces output filter requirements The analog power filter consists of C16 and C48 while the digital is supplied via diodes 010 and 011 and is filtered by C14 and C47 It s bit clock which is 3 0MHz is derived from the 12MHz clock by the M4 ASIC U9 The D to A outputs are routed through differential amplifiers to the unit s output jacks via the analog output section see sec 3 20 Note that this product is specifically designed to take advantage of the A version of the AKM device This means that the unit is not compatible with the older AKM 4318 no A suffix part Alesis MidiVerb IV Service Manual 2 03 05 99 5 00 Digital Signal Paths The 80C31 MPU U14 controls all user interface functions of the M4 These functions range from handling the front panel buttons to continuously updating algorithm information to the M4 ASIC U9 Note that the 8031 data buss serves a dual purpose This buss multiplexes between low order addresses 1st 8 bits and data A latch contained in the M4 ASIC is used to hold the low order address half during 8031 read and write cycles The EPROM U2 is used to hold both program information and algorithm data The SRAM U10 holds system variables as well as user preset data MIDI is handled through the 80315 built in Read Ser
29. s MidiVerb IV Service Manual 5 03 05 99 0507 50 Q00C3 4xm PCB Retaining Clip Data 4 Encoder Cable Diagram 2 Alesis MidiVerb IV Service Manual 6 03 05 99 7 00 Test Procedures If possible user data should be saved an Alesis DataDisk is recommended for this task prior to any servicing This of course may not always be possible i e dead power supply bad reset signal corrupt data etc Saving user data may also be accomplished after unit functionality is restored i e power supply or reset line is repaired and prior to further servicing and testing The unit should always be reinitialized power unit up while holding PROGRAM and D buttons down after changing the EPROM SRAM 7 10 Self Test The built in test software as in other Alesis products provides basic diagnostics and tests to ensure unit functionality A MIDI cable MUST be inserted between MIDI IN and OUT before initiating the test To initiate the self test hold A and D while powering the unit up The unit will then proceed to test the following 5 LEDs All front panel LEDs are lit sequentially and immediately proceeds to the next test Y ROM CHECKSUM Checks the ROM s checksum for accuracy and immediately proceeds to the next test MIDI TEST Checks MIDI and immediately proceeds to the next test RAM TEST Checks internal memory for correct operation and immediately proceeds to th
30. ss capacitor Check for burnt or hot capacitors Replace if necessary Lights up but no display or function Faulty 8031 Replace and retest Replace reinitialize memory Power unit up while holding A and D and retest Unit crashed Reinitialize memory and retest Power unit up while holding A and D Faulty M4 ASIC Replace and retest Faulty LCD Module Test with known good front panel Replace if necessary Unit locked up display works but unit Loose front panel cable Reseat cable and retest doesn t function Faulty 8031 Replace and retest Garbled LCD display Unit crashed Reinitialize memory and retest Power unit up while holding A and D Faulty SRAM Reinitialize memory and retest Power unit up while holding A and D Faulty LCD Module Test with known good front panel Replace if necessary Faulty 8031 Replace and retest No audio Faulty M4 ASIC Replace and retest Faulty ADC Troubleshoot and repair as necessary Faulty DAC Troubleshoot and repair as necessary Faulty DIGPOT Troubleshoot and repair as necessary No effects wet output Faulty M4 ASIC Replace and retest Faulty 8031 Replace and retest Faulty DIGPOT Troubleshoot and repair as necessary Distorted output Input levels set too high Reduce input levels and retest Faulty ADC Troubleshoot and repair as necessary Faulty DAC Troubleshoot and re
31. supply voltage to prevent SRAM data corruption SRAM standby current should always be checked While the unit is off check the voltage across R21 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 ora short somewhere along the SRAM VCC line WARNING Danger of explosion exists if the battery is incorrectly replaced Replace only with the same type or equivalent type recommended by the manufacturer Battery Manufacturer Panasonic Matsushita Type BR2325 Rating 3V 5mA 3 00 Analog Signal Paths 3 10 Input The signal s from input jacks J3 right and J4 left mono are current limited by R20 R26 and have their impedances set at 1MQ stereo 500 mono by resistors R12 and R27 These signals are then buffered by U8C and U8D respectively before being sent to the input DigPots U6B U6A via A C coupling capacitors C4 and C2 After a small gain stage U8B U8A the signals are passed along to the ADC for further processing Alesis MidiVerb IV Service Manual 1 03 05 99 3 20 Output The differential outputs of the DAC U12 are converted to a single ended mode via U7B and U7A and their surrounding circuitry This circuitry also provides some low pass filtering These signals are then A C coupled by C1 and C3 before being sent to the output DigPots The output of the DigPots is buffered by UZD and U7C before bei
32. use overheating which may damage the product 8 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 9 Cleaning The product should only be cleaned as the manufacturer recommends 10 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 11 Damage to the Product Qualified service personnel should service the unit in certain situations including without limitation when Liquid has spilled or objects have fallen into the product The product is exposed to water or excessive moisture The AC power supply plug or cord is damaged The product shows an inappropriate change in performance or does not operate normally or The enclosure of the product has been damaged Oo o Alesis MidiVerb IV Service Manual iv 03 05 99 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 2 10 11 12 Visual Ins
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