Yamaha eq 90 m

Page 1

STEREO GRAPHIC EQUALIZER

EQ-90M

SERVICE MANUAL

I FRONT PANEL

tiAillAllA sardaoeooso communes seem m

0 o l_l

.359. Efimgifi News"
Eu passer emu. mi never.

t e z A A A A A A A A
e e 7 a v v v v v v v

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 inheranx to the
industry, and more specifically varnaha Products, are already known and understood by the users, and have therefore not been resuLed.

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 perform as specified. For these reasons, we advise all Yamaha product owners that all servibe required should be performed by
an authorind Val-naha Retailer or the appointed service representative.

.
IMPORTANT: The presenution or sale of fills manull to any ividual or firm does not canstilute authorization. Certification, recognition of any applicable technical
capabilities, or establish a principleagent relationship of any term.

The data provided is believed to be accurate and applicable to file unit(s) indicawd on the cover. The research, engineering, and service departments of Yamaha are continually
striving to improve Yamaha produclse Modifications are, therefore, ineviizble and specifications are subject to change without notice or obligation to retrofit. Should any
discrepancy appear to exist, please contact the distributors Service Division

WARNING: Static discharges can destroy expensive components Discharge any static eieetrieiry 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 lhe uni! OFF during disassembly and parts replacement, Recheck all work before you apply power in fine unit.

I CONTENTS

T0 SERVICE PERSONNEL IC BLOCKA~6
SPECIFICATIONS...............................I DISPLAY PIN CONNECTION
DIMENSIONS...................................I BLOCK DAIAGRAM.............
INTERNAL VIEW PRINTED CIRCUIT BOARD....................8~|I
REAR PANELSZ SCHEMATIC DIAGRAM.......... .....|2
LITHIUM BATTERY..............................3 WIRING.. .....|3
DISASSEMBLY PROCEDURES.......................3 PARTS LIST .llo~lq

§

YAMAHA

YAMAHA CORPORATION HAMAMATSU, JAPAN
1.2K-405 @8) Printed in Japan 89.7

Page 2

EO-VOM

I TO SERVICE PERSONNEL

1. Critical Components Information.
Components having special characteristics are marked
and must be replaced with parts having specifioations equal
to those originally installed.

. Leakage Current Measurement (For 120V Model Only).
When service has been completed, it is imperatiVe that you
verify that all exposed conductive surfaces are properly
insulated from supply circuits.

Meter impedance should be equivalent to 1500 ohm shunted
by 0.15uF.

Leakage current must not exceed 0.5mA.

Be sure to test for leakage with the AC plug in both polarities.

I SPECIFICATIONS

Input sensitivity .
Output voltage
Frequency characteristic (FLAT)
Equalizer level control
center Irequency
Variable range
Signal to noise ratio .
Total harmonic distortion (1 kHz. 1V)
Maximum continuous power output (1 kHz, Tl-ID 0.03%) ,,,,,,
Power requirements
USA and Canada models
Australia model .
General model

1V
5H2 - lOOkHz - 3dB

. SGHZ, 160Hz, 400Hz. lkHz, 2.5kHz. 6.3kHz, 16KH2

AClZOV 60HZ
ACZ40V 50H:
. ACllD/120/220/240V SO/GOHZ

I DIMENSIONS

EQUIPMENT
UNDEFI TEST

AC LEAKAGE TESTER
OR EQUIVALENT

E

®

WALL
OUTLET

D-

[22222222223
INSULATING TABLE

o POLARIZATION lU mod-Lonly)
This amplifier product is equipped with a polarized alterna-
tingmurrent line plug la plug having one blade wider than the
other). This plug will (it into the power outlet only one way.
This is a safety feature.

Power consumption
Dimensions (W x H x D) .

.................... 10w
. 366 X 94 X 306 mm
(14 3/8" X 3 3/4 X12')
3kg (Bibs. 1002)
Owner 5 manual, Pin-plug cord, Power cord

Weight (Net) .
Attached (item)

' Specrficallons and appearance may be changed without notice due to
continuous progress in development,

(U). . . U. S. A. model
(C) . . . Canadian model

(A) . . .Australian model
(R). . . General model

306

366

(I4~7/1Sl

:le;=|:l

Mefifirwmfb

94
l3~11ll6"l