Onkyo T 4087 Service Manual

Page 1

SERIAL No. 3219

ONKYO SERVICE MANUAL

SYNTHESIZED
FM STEREO/AM TUNER
MODEL T-4087

Silver and black models

UD, UDN, BUD, BUDN 120v AC, 60Hz
UG. BUG 220v AC. 50H:
uw, BUW 120 or 220V AC, 50/60Hz
UQA, UQB 240v AC SOHz

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 COMPONENTS WITH
ONKYO PARTS WHOSE PART NUMBERS APPEAR
AS SHOWN IN THIS MANUAL,

MAKE LEAKAGE-CURRENT OR RESISTANCE MEAS-
UREMENTS TO DETERMINE THAT EXPOSED
PARTS ARE ACCEPTABLY INSULATED FROM
THE SUPPLY CIRCUIT BEFORE RETURNING
THE APPLIANCE TO THE CUSTOMER.

ONKYO

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TABLE OF CONTENTS

Specifications .......................... 2
Service procedures ........................ 2
Block diagram ........................... 3
Exploded view ........................... 4
Parts list .............................. 5
Microcomputer operation .................... 6
Adjustment procedures ..................... 8
IC block diagram ........................ 11
Printed circuit board View .................. 15
Schematic diagram ....................... 17
Pc board-parts list ........................ 19

Packing View ........................... 24

Page 2

SPECIFICATIONS

FM:
Tuning Range:

Usable Sensitivity:

5 0dB Quieting Sensitivity:

Capture Ratio:

Image Rejection Ratio:
IF Rejection Ratio:
Signal-to-Noise Ratio:

Alternate Channel
Attenuation:

Selectivity:

AM Suppression Ratio:
Total Harmonic Distortion:

Frequency Response:

Stereo Separation:

Output Voltage:
Muting Level:

AM:
Tuning Range:

Usable Sensitivity:

Image Rejection Ratio:

lF Rejection Ratio:
Signal-to-Noise Ratio:
Total Harmonic Distortion:
Output Voltage:

General
Antennas:

Semiconductors:
Dimensions (WxHx D):

Weight:

Dimensions (WxHxD):
(with side panels)
Weight:

(with side panels)

87.9 - 107.5 MHZ
(ZOOkHZ steps) (D)
87.50 7 108.00 MHz
(50kHz steps) (G/W)
Mono: 10,3dBf, 0.9uV,
IHF (759)
17.2dBf, 2.0uV
16.0dBf, 1.7,uV
36.0dBf, I7uV

Stereo:
Mono:
Stereo:
1 ,OdB

lOOdB
100dB
Mono:

Stereo:

85dB
77dB

80dB [HF (i400kHz)
(Narrow) (D)

SOdB DIN (Narrow)
(:300kHz, 40kHz Dev.) (G)
5 SdB

Mono: 0.03%

Stereo: 0.07% (wide)
30 - 15,000HZ +0.5dB/
-1.5dB

45dB at lkHZ

33dB at 70 - 10,000Hz
0 ~ 1.5V

17.2dBf, 4.0;.(V

522 ~1611kHz

(9kHz steps) (G)

530 7 1610kHz

(IOkHz steps) (D)

25pV

40dB

40dB

40dB

0.7%

0 ~ 400mV

FM: coaxial terminal

AM: built-in loop
antenna and
external terminal
FETs: 8 TR: 39 ICs: 20
Diodes: 96 LEDs: 31
435 x 77 x 372mm
(17-18" x 3 x14-S/8)
4.4kg:, 9.71135. (G)

465 x 77 x 372mm
(18-3/8 x 3 x 14-5/8)
5,1kg., 11.2le (D)

Specifications and features are subject to change without

notice.

SERVICE PROCEDURES

1.

Replacement of lamp

This unit is used two lamps listed below.

Circuit no. Part no, Description
PLOOI 210149 PLl4V0.06AW-3.0.
Power indicator
PL902 210064A PL6,3V, 250mA. Dial plate
illumination
. Safety-check output

(Only USA, model)

After correcting the original service problem. perform
the following safety check before releasing the set to
the customer. Connect the insulating-resistance
tester between the plug of power supply cord and
nickel screw on the back panel.

Specifications: 3:3Mohm i 10% at 500V.

. Change of band step/de-emphasis

Universal models are equipped with a band step/
de-emphasis switch on the back panel. This switch is
set to following position.

Emphasis AM step
set position SOpsec. 9 kHz
other 75usec. 10 kHz

. Change of voltage

Universal models are equipped with a voltage selector
to conform with local power supplies. This switch is
located on the back panel. Be sure to set this switch
to match the voltage of the power supply in your area
before tuning the power switch on.

This switch is set to 220V at the factory: Voltage
is changed by sliding the groove in the switch with
the 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.

. Memory preservation

This unit dose 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 uanUgged. The
Unit must be plugged in and the power switch turned
on and off once in order to charge the super capacitor
of €409 Note that since this is not a permanent
memory, the power switch must be turned on and off
a few times each month to keep the back-up system
operable, The period of time during which memory
contents are preserved after power has last been
turned off varies depending on climate and the location
and placement of the unit, On the average,memory
contations are protected over a period of 2 weeks after
the last time power has been turned off, This period
is shorter when the unit exposed to very high humidity
or used in an area with an extermely humid climate,