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Alesis MidiVerb IV Service Manual‘

ii

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 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

Summary of Contents for MIDIVERB IV

Page 1: ...Alesis MidiVerb IV Service Manual i 03 05 99 Alesis MIDIVERB IV STEREO EFFECTS PROCESSOR Service Manual V 1 00 6 13 95...

Page 2: ...ervices 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...

Page 3: ...ch 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 Manufactu...

Page 4: ...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 c...

Page 5: ...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 Remem...

Page 6: ...s 3 5 10 RESET 3 5 20 M4 ASIC 3 6 00 The Front Panel 5 6 10 The Keypad 5 6 20 Display LEDs 5 6 30 Disassembly 5 7 00 Test Procedures 7 7 10 Self Test 7 7 20 Further Testing 7 8 00 Troubleshooting 8 9...

Page 7: ...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 pr...

Page 8: ...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...

Page 9: ...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 threshol...

Page 10: ...control of the M4 ASIC 44 SRAMWR SRAM WRite enable Enables writing to the SRAM directly under the control of the M4 ASIC 19 M12CLK 12 Mhz CLocK 20 M3CLK 3 Mhz CLocK 21 LRCLK Left Right CLocK Used to...

Page 11: ...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 fir...

Page 12: ...Alesis MidiVerb IV Service Manual 6 03 05 99 Diagram 1 Diagram 2...

Page 13: ...next test A ROM CHECKSUM Checks the ROM s checksum for accuracy and immediately proceeds to the next test A MIDI TEST Checks MIDI I O and immediately proceeds to the next test A RAM TEST Checks intern...

Page 14: ...ize 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 n...

Page 15: ...Alesis MidiVerb IV Service Manual 9 03 05 99 9 00 Schematics...

Page 16: ...Alesis MidiVerb IV Service Manual 10 03 05 99...

Page 17: ...Alesis MidiVerb IV Service Manual 11 03 05 99...

Page 18: ...Alesis MidiVerb IV Service Manual 12 03 05 99...

Page 19: ...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 ca...

Page 20: ...erb IV Service Manual 14 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 Produc...

Page 21: ...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 ex...

Page 22: ...Nibble Footswitch Mode see Footswitch Modes System Status Byte see System Status Byte Modulator Definitions 0 Pitch Bend 1 Aftertouch 2 Note Number 3 Velocity 4 Controller 0 123 Controller 119 Modulat...

Page 23: ...ays 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 PROGR...

Page 24: ...P ZNC 1 HOLDS REGULATOR 7805 TO PCB 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 2 27 0032 ASIC POT 4 CHANNEL DIGITAL M4 1 IC 2 11 7...

Page 25: ...P SMD 2 MAIN U7 8 SMI 2 64 0138 IC 74HC138 DEMUX DEC SMD 1 FP U3 SMM 2 50 4148 DIODE SIGNAL 1N4148 SMD 5 MAIN D7 D11 SMM 2 51 4401 TRANS 2N4401 NPN SMD 3 MAIN Q1 3 SMM 2 50 4148 DIODE SIGNAL 1N4148 SM...

Page 26: ...Alesis MidiVerb IV Service Manual 20 13 00 Service Manual History 6 13 95 V1 00 1st Release...

Page 27: ...CDATA 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 FROMADC 2 4 front panel 3 5 7 8 19 I I O ports 3...

Page 28: ...XD 3 S S1 1 sample and hold 2 Sigma Delta 2 SRAM 1 3 4 7 8 19 SRAMA0 16 4 SRAMCE 3 SRAMD0 7 4 SRAMWR 4 standby current 1 stereo output 2 SWITCHES ENCODER 7 T Transmit Serial Data 3 TXD 3 U U10 3 19 U1...

Page 29: ...Alesis MidiVerb IV Service Manual 23 03 05 99 NOTES...

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