Yamaha jx40 service manual

Page 1

JXA

SERVICE MANUAL

IFRONT PANEL

man low

.IXMI @ @

INN" VOLUME MASIEI VOL I_.____A_EGUA llERJ-J IEVERI PHONES POWER
I C O NTENTS
SPECIFICATIONS ...................... 2 PRINTED CIRCUIT BOARD ............... 4
GENERAL ADJUSTMENT AND CHECK ....... 2 SCHEMATIC DIAGRAM .................. 5
BLOCK DIAGRAM ..................... 4 PARTS LIST .......................... 6

SINCE 1887

YAMAHA

NIPPON GAKKI (30.. LTD, HAMAMATSU JAPAN

79 Nov. 1.5K Printed in Japan a?)

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JX40

.SPECIFICATIONS
OUTPUT POWER 30w (89T.H.D. 3%)
meur sensrvn'v PULL~GAIN HIGH ~39dB (9mVl
(at 1kHz) (push) Low -27da (35mV)
Ms-V PULL-GAIN HIGH -53dB l1.7mV)
Eavm. max.
VOLUME (pull) LOW -41clB (7mV)

FAT-1

INPUT IMPEDANCE HIGH 34OKQ, LOW BOKQ

NOISE -55dB (MAS. VOL 9min. VOLUME 9min.)
-35dB (MAS. VOL-Hoax. VOLUME Vmax.

PULL. G 9push)

-25dB (MAS. VOL -* max. VOLUME max.

PULLvG *pulli

REVERE Spring Type

HEADPHONE JACK ~8dB (0.3V) @ 30w 89

SPEAKER YAMAHA JA3066 (30 cm) x1

POWER CONSUMPTION Canadian Model 40W 0.5A

Other Models 65W

POWER SOURCE 120V AC fixed, or 110, 130, 220 or

240V AC selectable, 50/60 Hz

DIMENSIONS 508 x 450 x 210 mm
WxHxD l20"x17.7" x8.3"l
WEIGHT 142 kg (31 lbs 9 oz)

Specifications subject to change without notice.

.GENERAL ADJUSTMENT AND CHECK SPECIFICATIONS

For the measurements, use an oscillator with an output impedance of below 1K9, an oscilloscope and an AC voltmeter/

dB meter with an input impedance of over IOOKSI.

I. GENERAL ADJUSTMENT
Oldling Current Adjustment
Adjust the pot (35009) so that the voltage across the
terminals TP1 (+) and TP2 (-) on PM circuit board is
set to 5 i 1mV.
When readjusting all over again (2.9. when replacing
the power transistor), make sure to turn the pot full
counterclockwise.

O FIGJ

OPower Supply Voltage Check

Check to ensure that a voltage of 60V is obtained
across TP5 (+) and TP6 (~) and 25.5V across TP4 (+)
and TPG (-l.

.dling Current Power suoply Power Supply
5: lmv 25.5v (_) F 60V :31
TP2(-)0- L
res
TPI
(+)
BIAS W5
A DJ
TP4