Hitachi HCA 7500 Mk2 Service Manual

Page 1

TY No.238EGF

HITACHI

SERVICE MANUAL CA-7500M KI]

(- CONTENTS
SPECIFICATIONS ...................................... 1
FEATURES ................................................ 3
DESCRIPTION OF THE NEW CIRCUITS ........ 4
SERVICE POINTS ...................................... 6
ADJUSTMENTS ........................................ 8
CIRCUIT DIAGRAM ................................... 9
PRINTED WIRING BOARD .......................... 10
TROUBLESHOOTING ................................. 11
BLOCK DIAGRAM ..................................... 12
DISASSEMBLY AND REPLACEMENT .......... 12
REPLACEMENT PARTS LIST ...................... 13

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"SAFETY PRECAUTIONS

The following precautions should be observed when servicing.

1. Since many parts in the unit have special safety related characteristics, always use genuine Hitachi replace-
ment parts. Especially critical parts in the power circuit block should not be replaced with other makes.
Critical parts are marked with A in the schematic diagram and circuit board diagram.

2. Before returning a repaired unit to the customer, the service technician must thoroughly test the unit to
ascertain that it is completely safe to Operate without danger of electrical shock.

SPECIFICATIONS
Input sensitivityl- TUNER, AUX 104 dB
Impedance Total harmonic
PHONO (MM) 2.5 mV/iOO k-ohms, 47 k-ohms, distortion
22 k-ohms (20 Hz - 20 kHz)
PHONO (MC) 0.1 mV. 2.5 mV/lOO ohms PHONO Less than 0.005% at REC OUT leer 5 V
TUNER, AUX 150 mV/47 k-ohms TUNER, AUX Less than 0.005% at PRE OUT level 5 V
TAPE PLAY 150 mV/47 k-ohms Tone control
Max. input level BASS : 8 dB (50 Hz, 100 Hz turnover 3:
(1 kHz, T.H.D. 0.005%) 150 Hz, 300 Hz)
PHONO TREBLE -_+. 8 dB (10 kHz, 20 kHz turnover at
(MM, MC 2.5 mV) 260 mV 3 kHz, 6 kHz)
PHONO (MC 0.1 mV) 10 mV Loudness control
Output level/Impedance (Volume -30 d8) +8 dB (50 Hz), + 3 dB (10 kHz)
TAPE REC OUT 150 mV/600 ohms Subsonic filter 15 Hz (6 dB/octl
PRE OUT 1 V/600 ohms Mute -20 dB
Frequency Power supply AC 120 V 60 Hz, 220 - 240 V
characteristics N 50/60 Hz, 110 - 120 V ~ /220 -
PHONO (MM. MC) 20 Hz - 20 kHz (1 0.2 dB RIAA) 240 v ~50/6o Hz
TUNER. AUX 5 Hz - 100 kHz (12 d8) Power consumption 18 W (AC 120 V. 220 V - 240 V~l
Signal-to-noise ratio Dimensions 435 lW) x 83 (H) x 292 (0) mm
UHF. short-circuited. A Weight 4.5 kg
network)
PHONO (MM) 91 dB Specmcations and parts are subject to change for improvement.
PHONO (MC) 75 dB (input level 025 mV)

STEREO CONTROL AMPLIFIER
October 1980 TOYOKAWA WORKS