Alesis MMT-8 Service Manual
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Alesis MMT-8 Service Manual

Multitrack recorder
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ALESIS
MMT-8 (MT)
Service Manual
P/N: 8-31-0018-A

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Summary of Contents for Alesis MMT-8

  • Page 1 ALESIS MMT-8 (MT) Service Manual P/N: 8-31-0018-A...

  • Page 2: Preface

    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.

  • Page 3: Warnings

    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.
  • Page 4 Safety Instructions 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.

  • Page 5: General Troubleshooting

    (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.

  • Page 6: Table Of Contents

    6.00 Keypad Decoding ..................3 7.00 Metronome Output..................4 8.00 Updates and Corrections ................4 9.00 Troubleshooting..................4 10.00 Software History ..................5 11.00 MIDI Implementation ................8 12.00 Service Parts List..................14 13.00 Service Manual History................16 INDEX ....................... 17 Alesis MMT-8 Service Manual 1.00...

  • Page 7: General Description

    MMT-8's operation and the software history in section X.X. Most problems with the MMT-8 arise from either user error, or older software. The hardware is very simple and should normally prove to be problem to troubleshoot.

  • Page 8: Memory Mapped I/O

    SRAM during shutdown. Be aware that this can cause unusual unit lockups to occur if the circumstances are just right. For example, if an MMT-8 was shut off while in record mode, it's possible the 8031 was put into reset in the middle of writing a two byte pointer into memory. If only one of those bytes is written before reset, then it may point to an incorrect location in memory (battery backup holds the incorrect data).

  • Page 9: Midi I/O

    6. Always verify tapes after saving them. This helps reduce the chances of bad saves. Note however that the MMT-8 does not compare the tape to the contents of memory. It simply verifies that the information on the tape is valid MMT-8 data.

  • Page 10: Troubleshooting

    9.00 Troubleshooting Alesis MMT-8 Service Manual 1.00...

  • Page 11: Software History

    2/64. This would occur when changing length, quantizing, or copying any part or track. 7) Increased delay loops in display routines so that fewer LCD displays would be rejected in production. Alesis MMT-8 Service Manual 1.00...
  • Page 12 If no footswitch is plugged in at power on, the MMT-8 will assume a normally open footswitch. 3) If the start time of an unquantized note added to its duration results in the exact beat that the note would be quantized to, performing a quantize note start would result in a duration of 00/000 (e.g., note start of 001/47 duration 000/01 when quantized...
  • Page 13 3) If a part's length is changed from the top, any notes whose duration was a multiple of 256 clocks (2beats/64sub-beats, 5/32, 8/00, etc.) will have its duration altered such that the duration becomes 256 clocks (2/64) greater than it was previously. This is now fixed. Alesis MMT-8 Service Manual 1.00...

  • Page 14: Midi Implementation

    Following the above 5 bytes will be a block of data representing the contents of the MMT-8's memory. In order to optimize the data transfer, 8 MIDI bytes are used to transmit each block of 7 MMT-8 data bytes. If...
  • Page 15 3) There can be no gaps in the data. Part 01's data must follow directly after part 00's data, etc. 4) Locations 0CFH-0D0H (start of free memory) and 0D3H-0D4H (length of free memory) must be kept valid. Alesis MMT-8 Service Manual 1.00...
  • Page 16 * 96. The number of clocks must be divisible by 96. 3) Adding the number of bytes in a part to the absolute pointer of a part should point to 1 byte past the last byte of the part. Alesis MMT-8 Service Manual 1.00...
  • Page 17 Controller number 0-121 1vvvvvvv Controller amount 0000cccc MIDI channel number 0-15 00000000 not used 00000000 not used Program change format: 01111010 Program change flag (122) 1vvvvvvv Program number 0-127 0000cccc MIDI channel number 0-15 00000000 not used Alesis MMT-8 Service Manual 1.00...
  • Page 18 The sysex message can be as long as necessary by having consecutive 5 byte sysex packets. End of track format: 80H, # clocks lsb, # clocks msb, 0, 80H, 0, 0 The number of clocks should equal the number of beats in the sequence multiplied by 96. Alesis MMT-8 Service Manual 1.00...
  • Page 19 2) There cannot be more than 255 steps in a song. 3) Adding the number of bytes in a song to the absolute pointer of a song should point to 1 byte past the last byte of the song. Alesis MMT-8 Service Manual 1.00...
  • Page 20 ALESIS MMT-8 (MT) SCHEMATIC FILES Confidential Alesis Service Manual 8-31-0018-A...
  • Page 23 ALESIS MMT-8 (MT) HISTORY Confidential Alesis Service Manual 8-31-0018-A...
  • Page 39 ALESIS MMT-8 (MT) Confidential Alesis Service Manual 8-31-0018-A...

  • Page 40: Service Parts List

    MPS 2369 FAST TRANS 2-03-2369 Q5,6,11 MAIN 2N4401 NPN TRANS 2-03-4401 Q1-4,7-11,ECO #10102 MAIN 12 MHz CER RES 7-01-0003 MAIN 2" SPEAKER 7-02-0001 XFORMER P3 7-40-0903 LITHIUM BATTERY 3.5V 7-05-0003 MAIN PCB, MT KEYPAD 9-40-1016 CASE TOP (BLK) 9-11-1035 Alesis MMT-8 Service Manual...
  • Page 41 R28,32 MAIN 560 1/8W 5% 0-00-0561 R71-74 MAIN 10K 9 PIN SIP 0-06-1039 MAIN KEYPAD 9-21-1003 CASE TOP ROUND RUBBER FEET 9-23-1004 CASE BOTTOM RUBBER STRIP 8-3/4 9-23-1007 INSIDE CASE BOTTOM DPDT SWITCH 6-02-0001 SI (POWER) Alesis MMT-8 Service Manual...

  • Page 42: Service Manual History

    13.00 Service Manual History 7/21/94 V1.00b Preliminary Release Alesis MMT-8 Service Manual...

  • Page 43: Index

    INDEX Alesis MMT-8 Service Manual 1.00...
  • Page 44 NOTES Alesis MMT-8 Service Manual 1.00...

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