Hitachi UD 2 Service Manual

Page 1

UD-Z Mechanism

@HITACHI

English
Deutsch
Francois

SERVICE MANUAL

No.1139

English

This manual describes on the
standard chassis UD-2 and you
are requested to read this to
gether with the service manual
of each model.

CONTENTS
Specifications ............... 2
Description of new mechanism . . e . 2
Service points ............... 5
Exploded view .............. 23
Replacement parts lis! ......... 25

In dieser Anleitung wird das
Standard-Laufwerkchassis UD-2

beschrieben; fUr Wartungsar-
beiten ist daher die vorliegende
gemeinsam mit der Wartungs-
anleitung fijr das entsprechende
Modell zu verwenden.

Inhaltsverzeichnis

Technische Daten ............ 9
Beschreibung des neuen

Mechanismus .............. 9
Wavtungspunkte .............. 12
Auseinandergezogene Darstellung . .23
Ersatzteilliste ............... 25

Francis

Ce manuel décrit le chassis stan-
dard Ud-2 et nous recomman-
dons de le lire en mérne temps
que le manuel d'entretien de
chaque modéle.

Table des matiéres

Spécificaiions techniques ........ 16
Descrimion du nouveau mécanisme .16
Points de réparalion .......... 19
Vue éclatée ................. 23
Liste de piéces de rechange ...... 25

TAPE DECK MECHANISM

Dec. 1978

Page 2

UD-Z

English

SPECIFICATIONS

Track system
Motor 2-m otor system

Tape speed 4.75cm/s
Wow & flutter WRMS 0.04%
F,F. time 90 sec (C-60)

Rewind time 90 sec (060)

E rase head *

4-track, 2-channel

o Capstan driver DC motor (with frequency control governor)
0 Reel driver DC motor (with mechanical governor)

Heads Record/Play back head

0 Items marked differ depending on models. Specifications may be changed for improvement

without notice.

DESCRIPTION OF NEW MECHANISM

The role of the mechanism of a tape deck is very impor-
tant and the degree of rotation unevenness is determined
by this mechanism. This is not concerned only with ro-
tation unevenness but also affects tone quality; thus the

OUTLINE OF UD MECHANISM

The capstan and reel used to be driven simultaneously by
one motor in conventional cassette decks.

However, with this method, rotation vibrations or uneven
torque due to the uneven reel precision affects capstan
rotation, causing uneven speeds.

Now, with the UD mechanism, the drives of the capstan
and reel are independent; a frequency controlled motor is
used to drive the capstan, and a DC motor with a me-
chanical governor is used to drive the reel.

Tape running is not affected by the reel with this method,
also, the mechanism can be simplified.

An lC exclusively for Logic control has been developed
at the same time; it performs multi-mode control electri~
cally. As a result, the number of parts used is reduced
and the factors resulting in deterioration of performance
because of unevenness in quality of manufacture of me-

mechanism can be said to have great significance. Con-
cerning uneven rotation in particular, this was more than
0.15% in 1970 but in the past 2 or 3 years it has been
improved so that it is less than 0.1%.

chanical parts and assembly is decreased. Since the con-

trolling of the mechanism is done electrically, new auto-

matic functions such as auto-rewind, auto have become possible.

In this chassis, electrical parts including motor, solenoid,

etc. are operated by the mode control circuit.

Troubleshooting in this unit is done in the following way:

1. Check the operation of the electrical parts (shown in
the Table below) related to the set mode.

2. Classify whether the part malfunctioning is an electri-
cal part or mechanical part, and then proceed with
troubleshooting.

Mechanism-related troubleshooting is emphasized in this

service manual.

Refer to service manuals for respective models for electriv

cal circuits.

Electrical parts Mode
PLAY REW FF PAUSE STOP
Head plate solenoid O X X X X
Brake solenoid X 0 O X X
Reel drive motor Clockwise rotation Clockwise rotation Coun-terclockwise X X
rotation
Capstan drive motor 0 O O O O

0 shows operation mode.
X shows stop mode.

Rotation direction of the reel drive motor is that viewed from the motor pulley side.

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