Onkyo T 4120 Service Manual

Page 1

ONKYO

T-4120

SERIAL N0 3288

SERVICE MANUAL

SYNTHESIZED
FM STEREO/ AM TUNER

MODEL T-4120

Black model
BUDN, BUD 120V AC, 60 Hz
BUG 220V AC, SOHz
BUU, BUUX llO/l20/220/240V AC, SO/60Hz
BUQA, BUQB 240V AC, 50 Hz

SAFETY-RELATED COMPONENT WARNING! !
COMPONENTS IDENTIFIED BY MARK A ON
THE SCHEMATIC DIAGRAM AND IN THE PARTS
LIST ARE CRITICAL FOR RISK OF FIRE AND
ELECTRIC SHOCK. REPLACE THESE COMPO-
NENTS WITH ONKYO PARTS WHOSEPART
NUMBERS APPEAR AS SHOWN IN THIS
MANUAL.

MAKE LEAKAGE-CURRENT OR RESISTANCE
MEASUREMENTS TO DETERMINE THAT EXPOSED
PARTS ARE ACCEPTABLY INSULATED FROM
THE SUPPLY CIRCUIT BEFORE RETURNING

THE APPLIANCE TO THE CUSTOMER.

i TABLE OF CONTENTS

Specifications ........................
Service procedures ....................
Block diagram rrrrrrrrrrrrrrrrrrrrrrr
Exploded view .......................
Parts list ...........................
Block diagram of 1C ...................
Packing View ........................
Adjustment procedures .................
Pc board View/parts list .................

Main circuit .......................

Display/Operation switch ..............
Schematic diagram ....................

120V model

ONKYO
Ullllllll BUMPIINENIS

_1_

Other models ......................

....... 2
....... 2
....... 3
....... 4
....... S
lllllll 6
...... 10
...... ll
...... 13
...... l3
...... 19
...... 15
...... 15
...... l7

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SPECIFICATIONS

Tuning Range:

Usable Sensitivity:

SOdB Quieting Sensitivity:

Capture Ratio:
Image Rejection Ratio:

IF Rejection Ratio:
Signal-to-Noise Ratio:

Alternate Channel
Attenuation:

Selectivity:

AM suppression Ratio:

Harmonic Distortion:
87.9rlO7.9MHZ(200kHz steps: U.S.A model)
87.5»108.0MHZ(50kHz steps: European model)
87.9-107.9MH2(200kHz steps) or
S7.5-108.0MH2(50kHz steps) (Worldwide model)
Mono: [1.2dBf. 110 #V IHF

0.9 #V 75(1th DIN
Stereo: 2.0 #V 750hms
Mono: 11.2dBf, 2.0 #V 1HF(120V model)
Stereo: 17.2dBf. 4.0 #V (120V model) AM:
Mono: I] #V 7Sohms Tuning Range:
Stereo: 1,7 #V 750hms
Mono: 16.ldBL 3.5 #V (120V model)
Stereo: 36.1dBf, 35 #V (120V model)
1.5dB

Frequency Response:
Stereo Separation:

Muting Level:

Output Voltage:

Usable Sensitivity:
40dB (120V model) Image Rejection Ratio:
80dB (Other models) 1F Rejection Ratio:
90dB Signaleto-Noise Ratio:

Mono: 73dB Harmonic Distortion:

Stereo: 66dB Output voltage:
GENERAL:

50dB IHF(14OOI(HZ) (120V model) Dimensions(W>

SSdB DIN (i300kHz, 40kHz dev.) (Other models)

SOdB Weight:

Mono: 0.1%

Stereo: 0.2%

30-15. OOOHZ iltSdB
4DdB at (Hz

30:13 at 70-IU,000HZ
2.0 IV, 750hm
17.2dBf. 4.0/1 V
SOOmV (120V model)
750mV (Other models)

530-1620kHz(10kHz steps) (usA. model)
52271611kHZ( 9H2 steps) (European model)
530-1620kHz(10kHz steps) or

53l-I602kHz( 9kHz steps) (Worldwide model)
25 I V

40dB

40dB

40dB

0.8%

150mV

435 x 71 X 265mm
17-1/3" xz-ws" mos/s"
2.6kg.,5.71bs.

SERVICE PROCEDURES

1. Safety-check out
(Only U.S.A. model)
After correcting the original service problem.pertorm
the following safety check before releasing the set to
the customer.
Connect the insulating-resistance tester between the
plug of power suuply cord and chassis.

Specifications: 3.3Mohm i10% at 500V.

2. Memroy preservation
This unit does not require memory preservation batteries.
A built~in memory power back-up system preserves contents
of the memory during power failures and even when the
unit is unplugged. The unit must be plugged in and the
power switch turned on and off once in order to charge the
back-up system Note that since this is not a permanent
memorythe power switch must be turned on and off a few
times each month to keep the backup system operative.
The period of time during which memory contents are
preserved after power has last been turned off varies
depending on climate and placement of the unit.
0n the average, memory contents are protected over a
period of 3 to 4 weeks (a minimum of 2 weeks) after
the last time power has been turned off. This period is
shorter when the unit is exposed to very high humidity or
used in an area with an extremely humid climate.

3. Voltage Selector (Back Panel)

W models are equipped with a voltage selector to con-
form with local power supplies. Be sure to set this switch
to match the voltage of the power supply in your area
before turning the power switch out This switch is set to
220V at the factory Voltage is changed by sliding the
groove in the switch with a screwdriver to the right or
left. Confirm that the switch has been moved all the way
to the right or left before turning the power switch on.
Models without a voltage selector can only be used in
areas where the power supply is the same as that of the
unit.

Specifications and features are subject to change without notice.

4. Tuning Step Frequency Switch (Bank Panel)

W models are equipped with a switch for the AM (9kHz/
lOkHz) and FM (SOkHz/IOOkHz) bands The switch
should be set to the proper steps for the radio broadcast
frequencies in your area,

5. Changing the band step
With the exception of the models below, a BAND STEP
selector switch is not provided.

MODEL BAND STEP D767 R118
UD ZOOkHZ -> SOkHz Eliminated lSkQ ->30k§
UG/UQ SOkHz ->200kHz Additional 30kQ->15k5

In D767, 185133 (Part No. 223163) is used. R118,with
the muting amplitude determined, is on the bsck panel side
side of the main circuit printed circuit board assemdly

test points TP-l and TP-2.

FM

ZOOKHZ 41:? AM

D767 IOkHz
D763

Q75l