Jvc A X7 Service Manual

Page 2

Contents

_ Page
1. Specifications ........................ 1
2. Features ............................ 2
3. Removal Procedures .................... 2
3-(1) Top Cover ....................... 2
3-(2) Bottom Plate ..................... 2
4. Main Parts Location and Part Numbers ........ 3
5. Block Diagram ........................ 4
6. Adjustment Procedures
6-(1) Power Amplifier Center Voltage
Adjustment ...................... 5
6-(2) Idling Current Adjustment ............ 5
7. Exploded Views and Part Numbers .......... 6
8. Printed Circuit Board Ass'y and Parts List
8-(1) TXX-275B Equalizer Amp. 8: Switch
P.C. Board Ass'y ........... 8
8-(2) TXX-2768, C Driver Amp. 8: Power
Supply P.C. Board Ass'y ..... 10

1 . Specifications

Overall Specifications
Output Power : 90 watts per channel min. RMS
(TUNER, AUX, TAPE both channels driven, into 8
-> SF. OUT) ohms from 20 Hz to 20 kHz
with no more than 0.003 %
total harmonic distortion
93 watts per channel min. RMS
(8 ohms 1 kHz 0.0005 %
measured by HP-IB Audio
Analyze System)

Total Harmonic : 0.003 % at rated output, from

Distortion 20 Hz to 20 kHz, 8 ohms
(TUNER, AUX, TAPE 0.0005 % at rated output 1 kHz,
-> SP. OUT) 8 ohms (Measured by HP-IB
AUDIO ANALYZER SYSTEM)
0.02 % at rated output, from
20 Hz to 70 kHz, 8 ohms

: 0.002 % at rated output, 8 ohms
(60 Hz: 7 kHz= 4:1)

lntermodulation

Distortion
(TUNER, AUX, TAPE
-> SF. OUT)

Power Band Width : 5 Hz - 70 kHz (IHF, both
(TUNER, AUX, TAPE channels driven, 8 ohms,
-> SP. OUT) 0.02 % THD) +0

Frequency Response : DC - 400 kHz -3 dB
(TUNER, AUX, TAPE
-> SP. OUT)

Damping Factor : 100 (1 kHz, 8 ohms)

Input Sensitivity/Impedance

Phono-1, 2 (MM) : 2.5 mV/47 k ohms
Phono-1 , 2 (MC) : 200 [JV/100 ohms
TUNER, AUX, TAPE: 200 mV/47 k ohms

A-X7
No. 2554

8-(3) TAP-2858 Power Amp. P.C. Board Ass'y . . 13

8-(4) TSC-13ZB Pin Jack P.C. Board Ass'y ..... 15
8-(5) TPS-287C AC Unit P.C. Board Ass'y ..... 15
8-(6) TPS-287D AC Unit P.C. Board Assy ..... 16
8-(7) TPS-287E AC Unit P.C. Board Ass'y ..... 16
9. Packing Materials and Part Numbers .......... 17
10. Accessories List ....................... 17
11. A-X7 Schematic Diagram ................. 18
12. Parts List with Specified Numbers for
Designated Areas ...................... 20
Warning:

When replacing the parts marked with A , be sure to
use the designated parts to ensure safety.

Signal-to-Noise Ratio
Phono-1, 2 (MM) :85 dB (IHF,A net, short circuit),
82 dB (new IHF)
:69 dB (IHF, A net, short circuit),
75 dB (new IHF)
TUNER, AUX, TAPE: 110 dB (IHF, A net, short

circuit), 85 dB (new IHF)

Phono-1, 2 (MC)

Tone Controls
BASS : :8 dB (100 Hz)
TREBLE :i8 dB (10kHz)
Muting : -20 dB
Subsonic Filter : -6 dB/Oct. (18 Hz)
Phono Equalizer Section
(Phono -> REC. OUT)
Phono Overload
Phono-1 , 2 (MM)
Phono-l, 2 (MC)
RIAA Phono
Equalization : 10.2 dB (20 Hz - 20 kHz)
Total Harmonic Distortion
Phono-1, 2 (MM) : 0.002 % at 10 V output,

: 300 mV at 1 kHz, 0.001 % THD
: 23 mV at 1 kHz, 0.002 % THU

20 Hz - 20 kHz
Phono-1 , 2 (MC) : 0.005 % at 10 V output,
20 Hz - 20 kHz

Rec. Output/Impedance : 200 mV/680 ohms

Dimensions : 5-1/2"(H) x 17-3/4"(W) x
163/ "(0)
(13.9 cmlH) x 45.0 cm(W) x
42.6 cm(D)

Weight : 26.4 lbs (12 kg)

Power Source and

Power Consumption : See page 20.

Design and specifications subject to change without notice.

Page 16

8-(6) TPS-287D AC Unit P.C. Board Assy

[Employed only on (P) & (U) types]

Fig. 12
Capacitor Others J
Item No. Part Number Rating Description Item No. Part Number Rating Description
0001 QF29010-103 0.01pF Film QMC0637-004 AC Outlet
QSR0085-001 U Voltage Selector
E301203002 Circuit Board
I
8-(7) TPS-287E AC Unit P.C. Board Ass y
[Employed only on (E), (Al 8: (B) types]
~* .;.1:: 11:1: ;:ii} ; 1*
Mommax®®¢1®1®e @ Q
5"!" 1! «fig. x! 62
hi' .mbdfi) Etflzzfvt :1 :«
a it '3 ll
fi 30 d g, V e LQD 44%.
s 5' V J a 9 {I
:i'liuuttiwH*:,u»t::..~i:
a 1*
:13 . ~
+ 'l 1?
res-2821
, 4 V, : ; 5 i v; \
Fig. 13
Capacitor Others
Item No. Part Number Rating Description Item No. Part Number Rating Description
C001 OF29010-103 0.01pF Film E67448-001 Holder
QSR0085-001 U Voltage Selector
E301203-001 Circuit Board
A-X7

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