Hitachi D-E25 W - User Manual

Tk || Ne. 1445e
D-E25
©) HITACHI
(U, C, FS, BS, AU, W)
SERVICE MANUAL
Use
this
manual
together
with
the
ML-1
mechanism
Technical
Information
(No.1473).
HITA-00383
©
@
®@
©
®
CONTENTS
SPECI
CATIONS
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DiSASSOMDIY ..............ccessssssenssressccesassassensateseeanoeereneres 2
AGIUSTMOGNT saisdicsmdecepcavensetreicciemste nie ent 3
Inspection of MEChHANISM........... cc seeeteecreeteeeenes 4
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Schematic
diagram
...........cccssecsesssseecetessnecneceenerees
5
Circuit
board
diagram...........ceceesssececeeeeneaeeeneens
7
Exploded
view
(Cabinet)................::csccessssseneceeeeeees
10
Replacement parts list ............ cscs eeceeeeenecesseeens 11
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KEY TO ILLUSTRATIONS
1. Power (Mains) switch 10. Dolby NR switch
2, Playback indicator 11. REC Mute switch
3. Tape counter 12. Eject button
4. Recording indicator 13. Pause button
5. Level indicators 14. Stop button
6. Recording level controls 15. Fast forward button
7. Headphone socket 16. Playback button
8. Microphone sockets 17. Rewind button
9. Tape select switches 18. Record button
SAFETY
PRECAUTION
The following precautions should be observed when servicing.
1.
Since
many
parts
in
the
unit
have
special
safety
related
characteristics,
always
use
genuine
Hitachi’s
replaemeent
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.
Printed by: Schaltungsdienst Lange, Berlin (Germany)
SPECIFICATIONS
AND
PARTS
ARE
SUBJECT
TO
CHANGE
FOR
IMPROVEMENT
STEREO
CASSETTE
TAPE
DECK
December
1980
TOKAI
WORKS
LE ae A RE AL TS, eT RTE EAN eee PE ALE ae TEE RE EAN Se oe ree eh se Tw ea on

Summary

Safety Precautions

Specifications

Disassembly

Adjustment Procedures

Tape Speed Adjustment

Adjusts playback speed using test tape and a variable resistor.

Head Azimuth Adjustment

Adjusts head azimuth for optimal playback, requiring a test tape.

Playback Gain Adjustment

Sets playback gain to a specific voltage level using a test tape.

Level Indicators Calibration

Calibrates level indicators to show 0 dB with a specific input signal.

Bias Frequency and Voltage Adjustment

Adjusts bias frequency and voltage for optimal recording characteristics.

Bias Current Adjustment

Adjusts bias current for proper recording levels.

Record;Playback Output Level

Sets output levels for recording and playback, ensuring accuracy.

Dolby NR Adjustment

Calibrates Dolby NR circuitry for effective noise reduction.

Dolby NR Bias Current Adjustment

Fine-tunes bias current for Dolby NR boost when activated.

Inspection of Mechanism

Lubrication Guide

Schematic Diagram

Circuit Board Diagram

Exploded View (Cabinet)

Replacement Parts List

Hitachi D-E25 W Specifications

General

Track System	4-track, 2-channel stereo
Type	Cassette Deck
Heads	1 x playback, 1 x record/playback, 1 x erase
Tape Type	Normal, CrO2, Metal
Wow and Flutter	0.08% WRMS