Onkyo TAR 77 Service Manual

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I'A-R77

SERIAL NO. 3144

ONKYO® SERVICE MANUAL
STEREO CASSETTE
TAPE DECK

MODEL TA-R77

UDN, UDC, UD l20V AC, 60Hz
UGV, UG 220V AC, SOHZ
UW 120 or 220V AC, 50/sz
UQA, UQB 240V AC, SOHz
SAFETY-RELATED COMPONENT WARNING SPECIFICATIONS
COMPONENTS IDENTIFIED BY MARK A ON THE Track system: rack, 2-channel stereo
SCHEMAI'IC DIAGRAM AND IN THE PARTS LIST ARE Recording System: AC bias
CRITICAL FOR RISK OF FIRE AND ELECTRIC SHOCK. Erasing System: AC erase
REPLACE THESE COMPONENTS WTTI-I ONKYO PARTS Tape Speed: 4.8 cm/scc
WHOSE PARTS NUMBERS APPEAR AS SHOWN IN THIS Wow and Flutter: 0.04%(WRMS)
MANUAL. Frequency Response: m-16,0(I) Hz (Normal)

MAKE LEAKAGE-CURRENT OR RESISTANCE
MESUREMENTS TO DETERMINE THAT EXPOSED PARTS
ARE ACCEPT ABLY INSULATED FROM THE SUPPLY CIR»
CUTT BEFORE RETURNING THE APPLIANCE TO THE
CUSTOMER.

ONKYO.
Alllllll BflMlllNflllS

S/N Ratio:

Input Jacks:

(SO-15,000 Hz :3 dB)
20-18,000 Hz (High)
(30-17000 Hz :3 dB)
20-20000 Hz (Metal)
(SID-18,000 Hz i3 dB)
Dolby NR out: 60dB (metal
position tape)
A noise reduction of 10 dB
above 5 kHz and 5 dB at 1 kHz
is possible with Dolby B. A
noise reduction of 20 dB at
5 kHz is possible with Dolby C.
Line IN: 2

Minimum input level: 50 mV

Input impedance: 50 kohms
DIN Jack: 1

Minimum input level:

0.] mV/l kohm
Input impedance:
2.7 kohms

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l A-R77

Line OUT: 2
Std output level: 500 mV
(0 dB)
Opt load impedance:
over 50 kohrns
DlN Jack: 1
Standard output level:
500 mV (at 0 dB)
Opot load impedance:
over 50 kohms
Motors: DC motor: 3
Heads: Sendust rec/pb head: 1
Ferrite erase head: 1
TR: 65 Diodes: 35
1C: 10 LED: 18
AC 220 V/SO Hz, 120/220 V,
50/60 Hz, and 2A0 V/SO Hz
30 watts

Output Jacks:

Semiconductors:
Power supply:

Power Consumption:

Dimensions: 435(W) x 1120-!) x 371(D) mm
(17-1/8" x 4-3/8" x 14-5/8)
Weight: 6.7 kg. (l4.8 lbs.)

Specifications and external appearance are subject to change
without notice because of product improvements.

FEATU R ES

Quick Reverse Operation With Photo Semr

A newly developed photo sensor is used to detect the point where
the direction of tape transport is reversed. This system makes it
possible to perform transport reversal in about 0.9 seconds. Since
tape transport is virtually uninterrupted, quick reverse is ideal for
continuous side A-side B playback and recording as well as endless
playback for background music.

Mlcrocornputerfiontrolled 3-Motor System

The tape transport system, along with the heads, determines the
performance level of a cassette deck. To guarantee extermely stable
and accurate transport, the TA-R77 uses 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 system and a
precision vertical cassette holder further enhance overall accuracy
and stability. As a result, wow and flutter is 0.04%. In addition,
separate DC motors drive the reel tables and head base. For ex-
traconvenience, the head assembly is constructed to move silently
with no annoying clicks.

Auto Space Rec Mule Button

Press mis button while youre making a recording to automatically
enter a blank section of tape about five seconds long. Once the
blank section has been entered, the TA-R77 will automatically
switch to the REC-PAUSE mode. To continue recording, simply
press the PLAY button. This function is useful for temporarily in-
terrupting recording, editting rape during dubbing and inserting
unrecorded sections long enough for the AMCS circuit to detect.

Dolby B and C Noise Reduction

Along with standard Dolby B NR, the TA-R77 also has the even
more effective Dolby C NR system. Dolby C NR reduces tape
background noise by 20 dB at 5 kHz, about 3 times more than
Dolby B NR. In addition to its wide band norse reduction,
Dolby C NR uses a sliding band technique that varies the band
width of noise reduction according to the input level, thereby
avoiding noise pumping. Dolby C NR also has an anti-saturation
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.

Auto Music Control System (AMCS)

TA-R77 has an AMCS function which automatically locates the
beginning of every song on a cassette in either the forward or
reverse direction. When the AMCS button is pressed during the
forward play mode, tape is rapidly wound to the beginning of the
next song and the first 10 seconds (approximately) is played. Then
the tape is rapidly wound forward to the beginning of the next song
and about 10 seconds is played. This process continues until the
FORWARD PLAY button is pressed to cancel AMCS and return
to normal palyback. When the AMCS button is pressed during the
reverse play mode, this process is performed in the reverse direction.

Bright Peak level Meters

The left and right peak level meters react instantaneously to signals
and the twocolor layout assures that you wont miss any potential-
ly harmful input signals when setting the recording level.

Erasure Prevention Tab Monitor

The absence or presence of the erasure prevention tabs for cassette
sides A and B is automatically detected and displayed. This assures
that there will be no mistakes when youre about to make an im
ponant recording.

SERVICE PROCEDURES

1. Replacing the lamps
This unit uses the lamps listed below.

Cirtuit No. Parts No. Description

PL90! 210165 14 V, 150 mA, Dial plate
illumination

PL902 210149 PLl4V0. 06AW-3.0,
Power indicator

210169 PLl4V0. 06AW-3.0,

Power indicator (Black
type)

Caution; Before replau'ng the lamps, be sure to unplug the power

supply cable.

2. Insulation resistance mesurernent
Connect the insulating-resistance tester between the plug of
power supply cord and chassis.
Specifications; D model

GIW models

500 V £0.33 Mt]
500 V more than 10 Mt}