Yamaha jx50 service manual

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SERVICE MANUAL

.FRONT PANEL

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I CONTENTS
SPECIFICATIONS ...................... 2 PRINTED CIRCUIT BOARD ............... 4
GENERAL ADJUSTMENT AND CHECK ....... 2 SCHEMATIC DIAGRAM .................. 5
BLOCK DIAGRAM ..................... 4 PARTS LIST .......................... 6
(a YAMAHA
2 NDUON UAKKI CU LYD HAMAMATSU JAPAN

79 Nov. 1.5K Primed m J-pan a!

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1X50

I SPECIFICAI'IONS

our")? men sow rearwoam

mvur ssuswmr PULL-GAIN HIGH -37 as (i saw)

in mm «mm LOW -25 as («mvi

WV PULL-GAIN HIGH -51 as (2.2mVl
IONOL mar.
mum (pull) LOW ~39 d8 (BMW
FAT *1

INPUT IMPEDANCE HIGH :MOKQ LOW SOKQ

NOISE 5563 (MAS. VOL *min. VOLUME *rnin.)
v35¢8 (MAS. VOL *mu. VOLUME "mx.

PULL. G *WSII

-25d8 (MAS. VOL *mu. VOLUME *mex.

PULLG *pull)

REVEHI Spring Typo

HEADPHONE JACK -8 dB (0.3V) 0 50W 89
SPEAKER YAMAHA Jmfi (30 en 1: I
POWER CONSUMPTION Can-dion Model 75W IA
Other Models 1 2M

POWER SOURCE 120V AC lured. or "0, 130, 220 or
240V AC locublo. SOISO H1

DIMENSIONS 5 x 50 x 210 mm
WuHIO 21.4"x17.7"x8.7"
WEIGHY 15.2 kg (33 lb! 8 all

specification: white! to change without action.

.GENERAL ADJUSTMENT AND CHECK SPECIFICATIONS

For the measurements. use an oscillator with an output impedance of below "($2, an oscilloscope and an AC voltmeter/

dB meter with an input impedance of over IOOKQ.

I. GENERAL ADJUSTMENT
Oldling Current Adjustment
Adiust the pot (35009) so that the voltage across the
terminals TP1 (H and TP2 (-i on PM circuit board is
set to 5 t lmV.
'When readjusting all over again (es. when replacing
the power transistor), make sure to turn the pol lull
counterclockwise.

FIG. I

Idling Current
51 law

Power Supply

OPower Supply Voltage Check
Check to ensure that a voltage of SUV is obtained
across T95 (H and TP6 l-) and 23V across TP4 (4-)
and TP6 l-l.

POW!" Supply