Akai AC 425 K Service Manual

Page 2

CONTENTS

SAFETY INSTRUCTIONS .......

INFORMATIONS
SPECIFICATIONS .........
CONTROLS ..................
I. DISASSEMBLY .....

ll. PRINCIPAL PARTS LOCATION IIIII
III. DISASSEMBLY OF MAIN COMPONENTS...
IV. MECHANICAL ADJUSTMENT...
V. ELECTRICAL ADJUSTMENT .....

VI. PARTS LIST .............
VII. ABBREVITIONS ........

SAFETY INSTRUCTIONS

PRECAUTIONS DURING SERVICING

i Farts identified by the i t) symbol parts are critical
tor safety. Replace them only with parts whose
numbers are specified

In addition to satety. other parts and assemblies are
specified for contormanoe with such regulations as
those applying to spurious radiation.

These must also be replaced only With spectfied
replacements.

Examples RF converters. tuner units. antenna seleaioh
switches. RF cables. noiseblockmg capacitors.
noise-blocking filters. etc.

3 Use specified internal Wiring. Note especially:

1) eres covered with Pvc tubing

2) Double insulated wires

3) High voltage leads

Use specified insulating materials for hazardous live
parts Note especially:

I) Insulating Tape

2) PVC tubing

3) Spacers (insulating beware)

4) Insulating sheets for transistors

5) Plastic screws tor fixing micro switches

.When replacing AC primary srde components
(transformers. power cords. noise blocking capacitor.
etc.) wrap ends of wires securely about the terrninats
before soldering

\fiaéofiy

Make sure that wires do not contact heat generating
parts (heat sinks. Ddee metal film resistors. tusiole
resistors. etc.)
7. Check it replaced wires do not contact sharply edged
or pointed pans.
9. Also check areas surrounding repaired parts.
9. Make sure that foreign obiods (screws. solder droplets.
etc.) do not remain inside the set.
MAKE YOUR CONTRIBUTION TO PROTECT THE
ENVIRONMENT
Used batteries with the ISO symbol for
reading as well as small accumulators
(rechargeable batteries). mini~battaries
(cells) and starter batteries should not
be thrown into the garbage can
Please leave them at an appropriate depot.
SAFETY CHECK AFTER SERVICING
Alter servicing. matte measurements of leakage-current
or resistance in order to check it exposed pans are
acoeptably insulated from the supply circuit.
The leakage-current measurement should be done
between accessible metal parts, (such as chassis.
ground terminal, microphone jacks. signal input/output
connectors. etc.) and the earth ground through a resistor
at 1500 ohm paralleled with a 0.15 p F capacitor. under
the unit's normal working condition
The leakage-current should be less the 0.5rnA rrns AC.
The resistance measurement should be done between
aocessible exposed metal pans and power cord plug
prongs with the power switch 'ON' (it included). The
resistance should be more than 2.2Mohms.

N

a

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PRECAUTIONS IN REPAIRING

When repairing or adjusting the umt please note the

roiiowing points

LDo not put excessive pressure on the mechanical
pan. (operation part), including the pick-up block as
extremely high mechanical precision is required in
these parts

2.When the base is removed tor repair or adjustment.
Make sure that there are no metal ODJECIS between
the P C board or the mocha pans and the base.

3.The Micro-Computer and the CD Signal processing
ICs may be damaged by static electricity or leakage
Irorri a soldering iron during repairing. While soldering.
please take the precautions against leakage as in
the illustrahon.

GND

4.00 not loosen any screws in the pickup block.
Please reler to NOTE when replacing the pick up
block.

5 To avoid hazardous inVisible Laser Radiation. do not
look at the Laser Beam (Objective lens) directly.
6.0n model for some countries. laser warning labels
are affixed on and inside ol the unit as shown below.
For your salety, read these labels carelully before

repairing or adjusting the unit.

CAUTION

The use at controls or adjustments or the pertormance

01 procedures other than those specified herein may

result in hazardous radiation.

[ EUROPE. SCANDINAVIA. UK and AUSTRALIA ]

oussi LASER ewoouor
«usszi LASER moon

mom: 1 uses wt:
xussr use: wmur

Label artixed on the rear panel or the unit

cwriori- truth-1E use! amnion man oven
mo rumour puma: Avon EXPOSUREYDIEAM
Ao-VZtisn usmtia LAsiaarqunc veo n-.
«we mien-(pummel: El due at swam
uwbeAanvuse fol araAuuc

mo AvanAEssa M suomuirirus oulYEr

usm am ALWMNA Mmflmm usumg.
IVLLE

5 i rag gums

VARNING ounuo LAIEhsVKAuima m ppm
on m wrap ow "mm Al ulKDFrFLAD
mum SJ mum

Label affixed on the CD MECHA BLOCK