Onkyo TA 2056 Service Manual

Page 1

ONKYO SERVICE MANUAL

ST EREO CASSETTE

TAPE DECK
MODEL TA-2056

Black and silver models
UDN, UDC, UD 120V AC, 60Hz
UG 220V AC, SOHz
UW 120 or 220V AC, SO/60Hz
UQA, UQB 240V AC, 50H:

SAFETY-RELATED COMPONENT WARN INGI !

COMPONENTS IDENTIFIED BY MARK 32 ON
THE SCHEMATIC DIAGRAM AND IN THE PARTS
LIST ARE CRITICAL FOR RISK OF FIRE AND
ELECTRIC SHOCK. REPLACE THESE COM-
PONENTS WITH ONKYO PARTS WHOSE PARTS
NUMBERS APPEAR AS SHOWN IN THIS MANUAL.

MAKE LEAKAGE-CURRENT 0R RESISTANCE
MEASUREMENTS TO DETERMINE THAT
EXPOSED PARTS ARE ACCEPT ABLY IN-
SULATED FROM THE SUPPLY CIRCUIT BEFORE
RETURNING THE APPLIANCE TO THE
CUSTOMER.

(ONKYOQ
LIIIIIIII BflMPflNEle

SPECIFICATIONS

Track Formal:
Erasing System:
Tape Speed:

Wow & Flutter:
Frequency Response:

Signal-lo-Noise Ratio:

Input Jacks:

Outputs:

23imax

4 tracks,2 channels
AC erase
4t8cm/sec.(1-7/8 i.p.s.)
0.045%(WRMS)
20-17,000Hz(30-16,000Hzi 3dB)
(normal positon tape)
20-18,000Hz
(30-17,000Hzi 3dB)
(high position tape)
20-19,000Hz
(30-18,000Hzi3dB)
(metal position tape)
60 dB (metal position tape,
Dolby NR out)
A noise reduction of IO dB avove
5 kHz and 5 dB at] kHz is possible
with Dolby B NR.A noise reduction
of20 dB atS kHz is possible with
Dolby C NR,
Mic Jaeks12

Input Sensitivity:

0.3mV/600 ohms

Input impedance: 5.6 kohms
Line IN:2

Input Se nsitivity: 60mW

Input impedance: 50 kohms
Line Out: 2

Std output level: 500mV(OdB)

Opt load impedance:

over 50 1(0th

Headphone Jack: 1

Optload impedance:

8-200 ohms

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TA-2056

Motors: DC servo motor:1
DC motor: 2
Heads: Rec/PB head: Special Hard
Pemalloy Combination
Erase head: Ferrite
Semiconductors: TR: 84 Diodes: 24 IC: 18

LED: 24
Power Supply: AC120V/60 Hz
Power Consumption: 34 watts

Dimensions: 435(W)>< 112(ll)>< 372(D)mm
(17-1/8>< 4-3/8>< 14-5/8)
Weight: 65kg.(14.3lbs.)

Specifications and external appearance are subjectto
change without notice because ofproduct improvements

SERVICE PROCEDURES

1. [nstulation resistance melurement

Connect the insulating-reistanoe tester batween the plug of
power supply cord and chassis,

Specificationsg500 V mone than 10 MO

2. Replacing the lamps
This unit used the lamps listed below,

Circuti No. Parts No. Description
Mechansi s m 24606173 SOmA, 14V. Lamp
1453

PL601 210090 150mA,l4V.Lamp
PL-902 210172 0.06A l4V.Lamp

CAUTION:Before replacing the lamps. be sure to unplug
the power supply cable,

3. Replacing the Dolby ICs

Because the TA-2056 is 3-head deckjt is equipped with a
4channel Doiby processor, Two channels are used exclusively
for encoding and the other two exclusively for decoding. If
there is a difference between the performance of the encode
and decode sides. both Dolby B and C NR will not operate
properly. To prevent this, the TA-2056 employs the HA-
12058-01. The appearanceis the same as the standard HA-
12058 with colored markings on the top surface of the 1C
When replacing the HA-lZOSS-Ol, the four [Cs (109,0110,
Q215,Q219) in the new one should all have the same color
markings.1fICs with the same color markings are not availa
ble. the Q109-215 and Q110-Q216 colors should be matched,
Thet is,the two encode ICs and the two decode [Cs must
always be of the same color although it is possible to use
different colors on the encode and decode sides when nece-
ssarv,

FEATURSE

Three Heads with Special Hard Permalloy

For Superior Metal Tape Performance

Having three heads you means you can monitor the
actual recorded signal as you record instead ofrewin-
ding the tape to check your recording afterward, The
3-head system also has the advantage of making possir
ble the use ofseparate record and playback gaps, each
optimized for its own task. The special hard permalloy
head formulation boasts the high saturation flux den-
sity and abrasion resistance needed for true metal

tape compatibility.

ACCUBIAS for the Best Performance With Any Tape
The ACCUBIAS system fine tunes the recording bias
to get optimum performance with any kind of tape
(notnecessary with metal tapes). By setting precisely
the correct bias level, you are assured of obtaining
the flattest frequency response and highest signaLto-
nosise ratio that each is capable ofproducing.

Dual Sensor Real Time Tape Counter

The tape counter circuit measures the Speed of both
tape reels and compares them by microcomputer to
provide precise remaining of readings 0ftime. This dual
sensor technique eliminates small errors in time caclur
lations caused by slight variations in tape thick nesses
between different manufacturers to give the most accu-
rate timc indications possibie.

2-Motor Tape Transport with Separate Head Assembly
Motor

The tape transpors system,along with the heads, deter
mines the level of performance ofa cassette deck. To
guarantee extremely stable and accurate transport this
unituses a DC servo controlled capstan motor. This
motor is unaffected by fluctuations in the power supply
voltage and frequency or instantaneous changes in
load, A highly reliable, simple drive transmission sys
tem and precision vertical cassette holder further
enhance overall accuracy and stability. As a result, wow
and flutter is under 0_045%. in addition.separate DC
motors drive the reel tables and head base and the
head assembly is constructed to move silently with no
annoying clicks.

Dolby B and C Noise Reduction

Along with standard Dolby B NR. this unit also has
the even more effective Dolby C NR system. Dolby C
NR reducas tape background nosise by 20 dB at 5 kHz,
about 3 times more than Dolby B NR. In addition
to its wide band noise reduction, Dolby C NR uses
a sliding band tech technique that varies the band
width ofnoise reduction according to the input level,
thereby avoiding noise pumping. Dolby C NR also
has an antivsaturatiori effect to reduce the chance of
tape saturation in the high range. All these features
combine to eliminate the adverse effects on tape sound
that other noise reduction systems can cause.

Remote Control Unit Terminal

With an optional remote control unit(such as the RC-
5T), this unitcan be controlled even while yon are
relaxing in your favorite chair. All transport modes are
inluded:record,play,fast forward,rewind.stop and pause.

Sensitive 2-Color lZ-Segment LED Level Meter with
Peak Hold

This easy-to-read meter has a peak hold function to
make it easy to determine the highest output level in a
program to be recorded so that the recording input
level can be set to the correct point.

42_
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Page 10

056

ADJUSTMENT PROCEDURES

PRECAUTIONS
1 Before adjustment, clean the following parts with an alcohol Blank tapes (completely erased)
moinstend swab, NORMAL ---------------------------- NEW UD 90
at: record/playback head at: erase head HIGku-H-u ------------ NEW XL-H 90
:1: pinch roller =1: capstan METAL ------------------- NEW MX 60
2. Do not use magnetized screwdriver for adjustments, Test tapes
3. Demagnetize record/ playback head with a head demagnetizerl VTT-658 : 10 kI-Iz.-15 dB
MTT-lll : 3 kHz,-10 dB
TEST EQUIPMENT/ TOOLS REQUIRED: MTT-lSO I Dolby level calibration
Audio oscillator 400 Hz tonc 200 nWb/m
Digital frequency counter
Oscilloscope
Attenuator
AC voltmer DC volmeter voltmeter
Connection of . . . Output Adjustment v _ '
Item instrument Line input Test tape Mode indicator point Adjust Ramarks
1 maybe TW-ZIII PB TW-ZIII Nil 35 t0 55gcm
IOTCIUC
Tape Frequency counter MTTAIII PB Frequency Semifixed 3,000 to 3.010
2 speed to LINE output counter on the moter Hz
terminal
Heed AC voltmeter and VTT»658 PB AC Head azimuth Maximum and See Fig.1
3 azimuth oscilloscope voltmeter screws same phase at Setthesemi-fixed
LINE output channels resistors R127 and R128
terminal L and R. to center position
Playback AC voltmeter MTT»|50 PB AC R-127tR)
4 level terminals TPVIOI voltmentel R-IZXtR) SROmV
and TP- 102
5 Meter MTTAISO PB Level R-321(L) OdB indicator
meter 11422111) lights on
Bias Fig.2 lkHZ,-20dB NEW XL-II REC/ AC R-443tl.) Same level INPUT VOLUME-"maximum
6 current and 90 PB voltmeter R-444tR) at REC/PB AUU BIAS VOLUME -----------
leHzAZDdB wuss-reenter
Record Fig.2 lkHz REC AC Anemwr or INPUT VOLUME-W
7 level PAUSE voltmeter AF 05c 0mm ------------ maximum
A BIA V L ME
REC/ AC R4010 Same level ,,CCU "Csente? U
PB voltmeter R4021 R) at REC/PB.
PLAY TORQUE ~~~~~~~~~~~~~ 30~60g/cm
FF REW TORQUE 70~l40g/cm
BACK TENSION ~3V5~6.5g/cm

-ll*

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