Onkyo TA 2080 Service Manual

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SERIAL N0 3068

ONKYO. SERVICE MANUAL

STEREO CASSETTE
TAPE DECK

Model TA-2080

TABLE OF CONTENTS

Item Page
Specifications 2
Features 2
Mechanism operation 3
Auto accu. bias circuit 4
Control panel circuit description 8
Voltage conversion 10
Component location 1 l
Eiploded View 12
Electrical adjustment procedures 14
Mechanism exploded view 17
Block diagram 19
Connection diagram 21 j
Mechanism operation-schematic diagram 22
Mechanism operation pcb. view 23
Auto accu. bias-schematic diagram 25
Auto accu. bias p.c.b. view 27
Rec./pb. ampli.-schematic diagram 29
Rec./pb. ampli. p.c.b. view 3]
Rec./pb. ampli. p.c.b.'parts list 33
Packing procedures 34 l

ONKYO.

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1. SPECIFICATIONS

TA-208O

Truck Format: 4 track, 2 channels Output jacks: Line out jacks: 2
Erase System: AC erase Standard output level
Tape Speed: 4.8 cm/sec 0.775 V (O VU)
Wow & Flutter: 0.045% (WRMS) Optimum load impedance
Fast Forward and over 50 kn,
Rewind Time: 90 sec (060) Headphones 8 :2 ~ 200 :1
Frequency Response: 20 ~ 20,000 Hz Metal Motors: 2 Motor system
20 ~ 18,000 Hz High ILL DC Servo-motor (CAPSTAN)
20 ~ 16,000 Hz Normal 5 Tag DC motor (REEL)
Signal-to-Notse Ratio: 62 dB (Metal tape: Dolby NR OUT) 1 3 [1 owcr Supply: AC 110/120/220/240V
Distortion: 2.0% (0 VU at 1 kHz) 50/60 Hz, AC 240V 50 Hz
Transistors: 119 or AC 120V 60 Hz
P 1 Power Consumption: 45W
IC 15 Dimensions: 438(W) x 160(H) x 365(D) mm
Diodes: 48 17-1/4" x 6-5/16" x 14-3/8"
LED: 2 Weight: 10.2 kg (22.5 lbs)
Input Terminals: Microphone jacks: 2 Accessories: Pin-Pin type connecting cords: 2
Minimum input level
0.3 mV/ 600 .0
Input impedance * Specifications and external appearance are subject to change
5 kn without prior notice because of product improvements.
Optimum load impedance
200 0 ~ 50 kn

Line in jacks: 2
Minimum input level 50 mV
Input impedance 100 kn

Current consumption (motor)

Playback: 70 - 100 mA
Recording: 70 - 100 mA
Fast forward: 90 - 130 mA
Rewind: 90 7 130 mA
Auto-Stop

Playback-Stop: 110 7 140 mA
FAR-Stop: 230 - 280 mA

2, FEATURES

Fully Automatic Aux-Bias Control

In order to ensure that the frequency response of each
cassette tape is as flat as possible, it is necessary to adjust
the recording bias for each tape accurately.

Onkyo's unique Auto Accu-Bias control in the TA-2080
performs this important task completely automatically.

So no matter what kind of tape is employed, the TA-2080
will automatically adjust for optimum recording quickly
and accurately.

3-Head Dock with High Quality Sendust Heads-Superb
Performance with the New Metal Tapes

The TA-2080 features separate recording and playback
heads incorporated in a single compact head case.

Each head has been designed and developed to achieve new
heights of hi-fi performance in the critical electromagnetic
transduction process. The use of Sendust, an extremely
robust alloy (of very high retentivity) in the core of each
head permits full advantage to be taken of high perfor-
mance metal tapes, resulting in an expanded upper dynamic
range and further reduction in distortion. Furthermore, the
3-head arrangement allows direct monitoring of just
recorded programs.

Mechanism specifications

1) Tape speed: 4.8 cm/sec. (3kl-lz +3Hz, 71 .SHz)
Use a standard test tape, VTT-658

(Ski-12) or equipment.
2) Wow and Flutter: Less than 0.045% (WRMS)
3) Take-up torque: 3S 7 60 gr-cm
4) RF. torque; 70 - 160 gr-cm
5) Rewind torque: 70 7 160 gr-cm

6) Rewind time: Less than 80 sec. (use a C-60

cassette tape)
7) Automatic shut-off
time: Less than 5 sec.
8) Timer start time: 1 sec. - 3 sec.

Special Laminated Core Erase Head

The special laminated structure of the erase head core is
more than sufficient to completely erase the newer metal
tapes where the coercivity is more than double that of most
other tapes.

Feather-touch Controls Plus Electronic Logic

Besides streamlining tape deck operations with efficient
and easy to use feather-touch push-button controls, the
TA-2080 is also equipped with electronic logic circuits to
protect both tapes and motor from undue strain.

This is accomplished by the incorporation of special circuits
connected the STOP position which momentarily stop the
tape whenever a switch to another transport mode is made.

Built-in Dolby NR System with Switchable MPX Filter and
Separate Dolby Recording Calibration Controls

The built-in Dolby NR system reduces characteristic tape
hiss by a very significant margin without affecting the
quality of sound. A special feature of this Dolby circuit is
the highly reliable single-chip 2-channel monolithic [C (one
channel being used for encoding and the other for decod-
ing) which ensures greater stability during Dolby recording

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and playback operations. Recording performance is also
improved by the Dolby recording calibration controls used
to ensure optimum recording settings with different types
of tapes. Furthermore, a built-in MPX filter removes the
pilot singal when recording FM broadcasts to prevent beat
interference.

High Grade Level Meters with Left/Flight 10-Point LED
Peak Indicator Lamps

With high grade logarithmic compressed wide range level
meters plus independent left/right high precision 10-point
LED peak indicator lamps, recording level settings are made
easier and more accurate. Even program sources of very

3. MECHANISM OPERATION

P Motor Pulley (42) /

Supply Reel Base (55)

Q:

Flywheel L (41)

Fig. 1 Mechanism operation diagram

1. Play Mode

At the start of play mode, solenoid C (105) is activated,
resulting in the sub-chassis assembly (17) being thrust
upwards, and the play idler (7) being pressed against the
drive pulley Z9) and take-up reel base (56) by the P-
coupled lever (49). thereby driving the take-up reel.
Play torque is adjusted by the amount of friction applied
to the piece of felt located in the center of the take-up
reel.

2. Fast Forward Mode
When the FF key is pressed, solenoid B (106) is acti-
vated and the FR idler (10) is pressed against the FR
motor pulley (13) and take-up reel base (56) by plunger
lever B (15) to commence fast forward mode. FF

/

G// ////. FR Idler (10)
/

3

TA-208O

wide dynamic range will be recorded true-to-the-original
with practically negligible distortion.

You are now the owner of a very high quality stereo
cassette tape deck. To ensure many long years of listening
enjoyment free of trouble, read this manual carefully and
familiarize yourself with all facets of operation. Failure to
do so may result in loss of performance, and also in possible
malfunction.

//,~FF1 Motor Pulley (13)

,Take-up Reel Base (56)
/

/Drive Belt (44)

Play Idler i7]

/

D'M Mia/(39) Note: the figure following

each part name is the
part number as shown
in the exploded View.

4 Flywheel R (40)

torque is adjusted by the amount of friction applied to
the piece of felt located in the FR idler.

3. Rewind Mode
Operation during rewind mode is much the same as
during fast forward, the main difference being that the
FR motor is made to rotate in the opposite direction
by having its polarity inverted. And since the motor
rotates in the opposite direction, the FR motor pulley
(13) is pressed against the supply reel base (55).