Sony tc wr 770 service manual

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TC-WR'I'IU/WRB'IS

SERVICE MANUAL

This photo is TC-WR875.

US Model
TC-WR875

AEP Model
UK Model

TC~WR770

Model Name Using Similar Mechanism TGWR97ES/WR87O

Tape Transport Mechanism Type TCM-2OOR5
SPECIFICATIONS

Recording system 4-track 2-channel stereo Outputs
Fast winding time Approx. 90 sec. (with Sony 060 cassette) Line outputs Rated output level 032 V at a load
3535 , AC '3' (phono jacks) impedance of
Signal-ioAnoise ratio (at peak level) 47 k ohms

Dolb NR switch d nce Over 10 k ohms

-y- OFF BAType 0N C-Type ON L "We
Cassette Headphones (stereo Output level 0 - 125 mW at a load

Type IV 7 phone jack) impedance of 32
(Sony METAL-S) 58 dB 66 B 3 3 ohms
Type II (Sony UX-S) 57 dB 65 dB 72 dB General
TYPE I (SONY HFS) 55 d3 63 dB 70 53 Power requirements US model :

Total harmonic distonion 1.0% (with Sony METAL-S cassettes)

Frequency response (DOLBY NR OFF)

Type IV cassette

30 - 18,000 Hz (t3 dB,|EC)

(Sony METAL-S) 30 - 14,000 Hz [13 dB 0VU(-4dB) recording)
Type " 559 so » 17 000 H + dB IE
(Sony UX-S) ' Z ('3 ' C)
Type I cassette
~ 1 _
(Sony HF-S) 30 5,000 Hz (+3 dB,lEC)
Wow and flutter :i: 0.09% W.Peak (IEC)
0.06% WRMS (NAB)
i0.16% WPeak (DIN)
Inputs
Line inputs Sensitivity 77.5 mV
(Ph°"° jacks) Input impedance 47 k ohms
MICHOFILM

Power consumption
Dimensions

Weig hi

Supplied accessory

120V AC, 60H:
AEP, Germany model:
220-230V AC, 50/60Hz
UK model:
240V AC. 50/60Hz
29 W
Approx. 430 x 135 x 355 mm (w/h/d)
(17 x 53/. x 14 inches)
including projecting pans and controls
Approx. 6.3 kg (13 lbs 15 oz)

Audio connecting cords (2)

Design and specifications subject to change without notice.

STEREO CASSETTE DECK
S ON Y;

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TC-WR770/WR875 I

FEATU R ES

For higher quality recording/playback

- The Dolby HX PHO' system which improves the linearity
of the tape's high-range response during recording.

. B and C type Dolby NFl systems which reduce tape
norse.

- Bias calibration to achieve the optimum bias current
setting for any tape (Deck B only).

For your convenience

- Quick reversing at the end of a tape to minimize
interruptions during playback and recording.

- Automatic tape type detection during playback and
recording.

- The AMS, Blank Skip and Memory Play functions which
provide easy access to a desired selection.

- A relay function for long recording and playback.

- Auto Play function which automatically starts playback
after tape rewinding to start.

- Timer-activated playback and recording through the use
of an optional timer.

- Synchronized dubbing at normal or high speed.

- Simultaneous Recording function for the simultaneous
recording of the same source to cassettes in both decks.

For easier operation
. Twin easy-to-read digital linear counters which show
the elapsed recording or playing time.

' Dolby noise reduction and HX Pro headroom extension manufactured
under license lrorn Dolby Laboratories Licensing Corporation. HX Pro
originated by Bang 5 Olulsen.

DOLBY. the double-D symbol [in and HX PFlO' are trademarks or Dolby
Laboratories Licensing Corporation.

Dolby noise reduction manufactured under license irom
Dolby Laboratories Licensing Corporation.
D0 LBY" and the doubleD symbol D0 are trademarks of
Dolby Laboratories Licensing Corporation.

SAFETY CHECK-OUT (US Model)

After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:

Check the antenna terminals, metal trim, metallized
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.

LEAKAGE TEST

The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5 mA (500 microampers). Leakage
current can be measured by any one of three
methods.

1. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers instructions to use these instru-
ments.

k)

A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.

3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The limit indication is 0.7SV, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)

Ta Expored Metal
Part: on Set

AC

0.15MF €15) voltmeter
(0.75 V)

F Earth Ground

IL

F ig. A. Using an AC voltmeter to check AC leakage.

SAFETY-RELATED COMPONENT WARNINGI!

COMPONENTS IDENTIFIED BY MARK A 0R DOTTED
LINE WITH MARK A ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.