Yamaha mu128 tone generator service manual

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YAMU -02596

.. , SERVICE MANUAL

TONE GENERATOR

MEIES

.CONTENTS
PANEL LAYOUT .........
SPECIFICATIONS ......
CIRCUIT BOARD LAYOUT .........
WIRING & BLOCK DIAGRAM .....
DISASSEMBLY PROCEDURE
CIRCUIT BOARDS .....................
LSI PIN DESCRIPTION...
IC BLOCK DIAGRAM ......
TEST PROGRAM ......
INITIALIZE ..............
ERROR MESSAGES; ..........
CONNECTING CABLES .....
MIDI IMPLEMENTATION CHART ......................................................... 30
PARTS LIST

OVERALL CIRCUIT DIAGRAM

sv [011451'

OYAMAHA

HAMAMATSU,JAPAN
0.32K-5351 (D Printed in Japan98.12

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MU128

IlVIIORTANT NOTICE

This manual has been provided for the use of authorized Yamaha Retailers and their service personnel. It has been assumed that
basic service procedures inherent to the industry, and more specifically Yamaha Products, are already known and understood by
the users, and have therefore not been restated.

WARNING: Failure to follow appropriate service and safety procedures when servicing this product may result in
personal injury, destruction of expensive components and failure of the product to per form as specified.
For these reasons. we advise all Yamaha product owners that all service required should be performed by
an authorized Yamaha Fletaiier or the appointed service representative,

IMPORTANT: This presentation or sale of this manual to any individual or firm does not constitute authorization, certifica-
tion, recognition of any applicable technical capabilities. or establish a principal-agent relationship of any
form.

The data provided is believed to be accurate and applicable to the unit(s) indicated on the cover. The research engineering, and
service departments of Yamaha are continually striving to improve Yamaha products. Modifications are, therefor, inevitable and
changes in specification are subiect to change without notice or obligation to retrofit. Should any discrepancy appear to exist,
please contact the distributor's Service Division.

WARNING: Static discharges can destroy expensive components Discharge any static electricity you body may have
accumulated by grounding yourself to the ground buss in the unit (heavy gauge black wires connect to this
buss).

IMPORTANT: Turn the unit OFF during disassembly and parts replacement. Recheck all work before you apply power to
the unit.

WARNING: CHEMICAL CONTENT NOTICE!

The solder used in the production of this product contains LEAD. In addition, other electrical / electronic and / or plastic (where
applicable) components may also contain traces of chemicals found by the California Health and Welfare Agency (and possibly
other entities) to cause cancer and / or birth defects or other reproductive harm.

DO NOT PLACE SOLDER, ELECTRICAL / ELECTRONIC OR PLASTIC COMPONENTS IN YOUR MOUTH FOR ANY REASON
WHAT SO EVEFII

Avoid prolonged. unprotected contact between solder and your skinl When soldering, do not inhale solder fumes or expose eyes to
solder / flux vapor!

if you come in contact with solder or components located inside the enclosure of this product, wash your hands before handling
food.

LUTHIUM BATTERY HANDLING

This product uses a lithium battery for memory back-up.

WARNING: Lithium batteries are dangerous because they can be exploded by improper handling. Observe the follow»
ing precautions when handling or replacing lithium batteries.

Leave lithium battery replacement to qualified service personnel.

Always replace with batteries of the same type.

When installing on the PC board by soldering, solder using the connection terminals provided on the battery cells.

Never solder directty to the cells. perform the soldenng as quickly as possible.

Never reverse the battery polarities when installing.

Do not short the batteries.

Do not attempt to recharge these batteries.

Do not disassemble the batteries.

Never heat batteries or throw them into fire.

ADVAFISELI

Lithiumbatteri-Ekspiosionsiare ved fejlagtig handtering. Udskitlning ma kun ske med batteri at samme fabrikat 09 type. Lever

det brugte batten tilbage til leverandoren.

VARNING

Explosionsfara vid feiakfigt batteribyte. Anvand samma batterityp eller en ekvivalent typ som rekemmenderas av

apparatlillverkaren. Kessera anvant batteri enlight fabrikantens instruktion.

VAROITUS

Paristo voi rajahtaa, jos so on virheellisesti asennettu. Vaihda paristo ainoastaan laitevalrnistaian suositteiemaan tyypplln. Havlta

kaytetty paristo valmistaian ohieiden mukaisesti.

The following information complies with Dutch Official Gazette 1995. 45; ESSENTIALS 0F ORDER ON THE COLLECTION OF

BATTERIES.

Please refer to the diassembly procedure for the removal of Back-up Battery.

- Least u voor het verwijderen van de backup batterii deze beschriivlng.

I WARNING

Components having special characteristics are marked Aand must be replaced with parts having specification equal to those originally
installed.