Yamaha spx900 service manual

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'EFFECT MODE (I717 IE-I') ............... : .......

DIGITAL MULTl-EFFECT PROCESSER

SEXSOO,

ICONTEN'IS (Elk) '
SPECIFICATIONS (fimAIiIi) .............................................. 2
CIRCUIT BOARD LAYOUT & WIRING (:memeRNiN) 4

PANEL LAYOUT (/\°$)l/I/47 *7 I) ..............................
BLOCK DIAGRAM (71:1 27747 77A)
DIMENSIONS ("hf) ........................
LSI DATA TABLE (LSIfi fi-Hfifififi) ~~~~~~~~~~~~~~~~~

IC BLOCK DIAGRAM (Ic7u 77E) ----------------------------- 11
DISASSEMBLY PROCEDURE (fifizflfi) ~13
CIRCUIT BOARDS (>- FEW.) ------------------ 16
CHECKS & ADJUSTMENTS (Nag 20/22
TEST PROGRAM (-71 I7n75A> ----------------- 24

MIDI DATA FORMAT (MIDI?-977I-7y I)
MIDI IMPLEMENTATION CHART -----------------

29/38
44
........ 45
PARTS LIST

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LM-

YAMAHA CORP.

HAMAMATSU, JAPAN

2.9K-I92 @ Printed in Japan EBJZ

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IMPORTANT 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 injLiry, destruction of- expensive components and failure of the
product to perform as specified. For these reasons, we advise all Yamaha product owners
that all service required should be performed by an authorized Yamaha Retailer or the

appointed service representative.

IMPORTANT: The presentation or sale of this manual to any individual or firm does not constitute
authorization, certification, recognition of any applicable technical capabilities, or
establish a principle-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 continuallyrstriving to improve Yamaha
products. Modifications are, therefore, inevitable and changes in specification are subiect to change without
notice or obligation to retrofit. ShOUId any discrepancy appear to exist, please contact the distributors
Service Division.

WARNING: Static discharges can destroy expensive components. Discharge any static electricity your
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 fl work before
you apply power to the unit.

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 following precautions when handling or replacing lithium batteries.

0 Leave lithium battery replacement to qualified service personnel.

Always replace with batteries of the same type.

When installing on the PC board, solder using the connection terminals provided on the battery cells.
Never solder directly to the cells. Perform the soldering 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.

ADVARSEL!
Lithiumbatteri. Eksplosionsfare.
Udskiftning ma kun foretages af en sagkyndig, 0g som beskrevet i servicemanualen.