Hitachi HCA-7500MKII Service Manual

CONTENTS
SPECIFICATIONS. ......... cece cccec ees eeweneeseennenes
FEATURES ..........ccccesecesceseeeneneeserseeeseneneenes 3
DESCRIPTION OF THE NEW CIRCUITS ........ 4
SERVICE POINTS. ............ceeceeceeeeneenerereanenes 6
ADJUSTMENTS. .........cccceceseccnsenseeenavesensanee 8
CIRCUIT DIAGRAM ...........:ccsceeseeveveesneeneees 9
PRINTED WIRING BOARD ............ccsseeseeeeees 10
TROUBLESHOOTING. ............cccceseeveeneneeseers 11
BLOCK DIAGRAM ...........::csneceeeeeneenneeeeennes 12
DISASSEMBLY AND REPLACEMENT .......... 12
REPLACEMENT PARTS LIST ...........:esceeeeeee
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 sensitivity/- TUNER, AUX 104 dB
Impedance Total harmonic
PHONO (MM) 2.5 mV/100 k-ohms, 47 k-ohms, distortion
22 k-ohms (20 Hz — 20 kHz)
PHONO (MC) 0.1 mV, 2.5 mV/100 ohms PHONO Less than 0.005% at REC OUT level 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 oa
Max. input level ; BASS + 8 dB (50 Hz, 100 Hz turnover at
(1 kHz, T.H.D. 0.005%) 150 Hz, 300 Hz} a
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 dB) +8 dB (50 Hz), +3 dB (10 kHz)
TAPE REC OUT 150 mV/600 ohms Subsonic filter 15 Hz (6 dB/oct)
PRE OUT 1 V/600 ohms Mute ~20 dB
Frequency Power supply AC 120 V 60 Hz, 220 — 240 V
characteristics ~ 50/60 Hz, 110 — 120 V ~ /220 —
PHONO (MM, MC) 20 Hz — 20 kHz (+ 0.2 dB RIAA) 240 V ~50/60 Hz
TUNER, AUX 5 Hz — 100 kHz (#9 dB) Power consumption 18 W (AC 120 V, 220 V — 240 V-~}
Signal-to-noise ratio Dimensions 435 (W) x 83 (H) x 292 (D) mm
(IHF, short-circuited, A Weight 4.5kg
network)
PHONO (MM) 91 dB Specifications and parts are subject to change for improvement.
PHONO (MC) 75 dB (input level 0.25 mV)
STEREO CONTROL AMPLIFIER
October 1980 TOYOKAWA WORKS