Hitachi AKG 88 Service Manual

Page 1

SERVICE MANUAL

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AK-G88

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CAUTION
DANGER

Invisible Iassr radiation when open and interlocks failed or defeated. AVOID DIRECT EXPOSURE TO BEA

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C ONTENTS

SPECIFICATIONS
SERVICE POINTS
ADJUSTMENT .......
TROUBLESHOOTING.
INTERFACE BLOCK DIAGRAM
CIRCUIT DIAGRAM ............
PRINTED WIRING BOARD.
WIRING DIAGRAM I,
BLOCK DIAGRAM
EXPLODED VIEW ..
REPLACEMENT PAR

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SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

AMUSEMENTKARAOKEPLALYER

DECEMBER 1992

HITACHI TELEVISION (TAIWAN), LTD.

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AKvGBS

. The caution labels on laser usage

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CLASS 1
LASER PRODUCT

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inside of the set is a laser component emitting a laser radiation over the limit for laser class 1.

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AK-G88

SAFETY PRECAUTIONS

The following precautions should be observed when servicing

I, Since many parts in the unit have special safety-related characteristics, always use genuine
Hitachi's replacement parts. Especially critical parts in the power circuit block should not be
replaced with other makers. Critical parts are marked with A in the circuit diagram and printed
wiring board.

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.

SPEC/FICA TIO/VS
' CD PLAYER SECTION
DISCS USED: CD/CD-Graphics
Playing time: Approx. 60 minutes/one side
Diameter: 12 cm/8 cm
SIGNAL FORMAT
Sampling frequency: 44.1 kHz

16 bit linear/channel
4.3218 Mia/second

Quantization number:
Transmission bit rate:
PICK-UP

System: Object lens drive system optical pick-up
Optical source: Semiconductor laser

- AMPLIFIER SECTION

Input sensitivity/Impedance: MK: 1, NIIC 2: 1,5 mV (10 kohms)
LINE W: 150 mV (47 kohms)
AUDIO OUTPUT: 150 mV
External speaker terminals
Suitable Impedance: 6 to 16 ohms
Headphones
Suitable impedance: Ste 100 ohms
20 W + 20 W (6 ohms, T,HDi 1%)

Output level:
Output Impedance:

Audio output:

GENERAL
Image output level: I Vp-p/75 ohms
RD output: UHF Channel 38 (Channel E30-E39 adjustable)
[UHF Channel C25 (Channel C22-C26 adjustablell
Aerial input: 75 ohms unbalanced type

AC lIO-IZOV. 200-220V, 230-240V. 50/50Hz (for W)
AC 110V 60Hz (for T)
130 W (for W)

Power supply:

Power consumption:

120 W (forT)
Dimensions: 435 W x i37 H x 420 D (mm)
Weight: 8.6 kg

Check that exposed parts are acceptably insu-
lated from the supply circuit before returning the
instrument repaired to the customer.

INSTRUMENT

E] (Exposed part)

. Checking method

Power (Operate) switch is set to ON.

Next, measure the resistance value between the
both poles of attachment cup (Power supply
plug) and the CD OUTterminai of rear plate and

check that the resistance value is 500 kohms or
more Insulation tester (DC 500V)