Yamaha k 902

Page 1

STEREO DOUBLE CASSETTE DECK

KX W492NV392/ K 902

SERVICE MANUAL

/ 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 injury, destruction of expensive components. and failure of the
product to perform as specified. For these reasons. we advrse all YAMAHA product
owners that any 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 of firm does not constitute
authorization, certification or recognition of any applicable technical capabilities,
or establish a principleagent relationship of any form.

The data provided is believed to be accurate and applicable to the uniI(s) indicated on the cover. The research,
engineering. and service departments of YAMAHA are continually striving to improve YAMAHA products.
Modifications are, therefore, inevitable and specifications are subject 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
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 part replacement. Recheck all work before

you apply power to the unit. /
'1
I CONTENTS
To SERVICE PERSONNEL ........................................... 1 KX-W492 BLOCK DIAGRAM ....................................... 20
FRONT PANELS .. .. 2 SCHEMATIC DIAGRAM .................. 21~23
REAR PANELS. 3 Kx-W392/K-902 SPECIFICATIONS
Kx-w492 SPECIFICATIONS 4 Kx-waszuK-soz INTERNAL VIEw..
KX-W492 INTERNAL VIEW ..... KX-W392/K-902 ADJUSTMENTS ................
DISASSEMBLY PROCEDURES . KX-W892lK-902 PRINTED CIRCUIT BOARD . .. ao~33
Kx-w492 ADJUSTMENTS ...... KX-W392lK-902 u-CCM DATA .............................. 34~36
KX-W492 PRINTED CIRCUIT BOARD Kx-wsszK-soz BLOCK DIAGRAM
Kx-w492 u-COM DATA .................... .16~18 PARTS LIST .....................................
. DISPLAY DATA ........................................................... 19
1 ° ° 5 3 7 _ YAMAHA CORPORATION

0.13tzx1.Hamamaisu apan
3KA504P ® 6) Printed in Japan H96 5

Page 2

KX-W492/W392/K-902
KX-W392/K-902

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

I TO SERVICE PERSONNEL

2. Leakage Current Measurement (For 120V Model only). WALL EQU|PMENT figflgfi
[ When service has been completed, it is imperative that you OUTLET UNDER TEST EQUIVALENT
verify that all exposed conductive surfaces are properly insu- ® :D___
lated from supply circuits. r
l ':
0 Meter impedance should be equivalent to 1500 ohm shunted 'NsfilfijéNG

by 0.15pF.
O Leakage current must not exceed 0.5mA.
0 Be sure to test for leakage with the AC plug in both polarities.

l

I *Dolby noise reduction manufactured under license from
Dolby Laboratories Licensing Corporation.
"DOLBY" and the double-D symbol DI] are trademarks of
Dolby Laboratories Licensing Corporation.

l

l

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, ELECTRICAIJELECTRONIC OR PLASTIC COMPONENTS IN YOUR MOUTH l
FOR ANY REASON WHATSOEVER!

Avoid prolonged, unprotected contact between solder and your skin! 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 ot this product, wash your
hands belore handling food.