Onkyo T 9990 Service Manual

Page 1

ONKY-OO416

SERIAL No. 3275

ONKYO SERVICE MANUAL

SYNTHESIZED
FM STEREO TUNER

MODEL T-9990

SAFETY-RELATED COMPONENT WARNING TABLE OF CONTENTS

COMPONENTS IDENTIFIED BY MARK [EON

Specifications ............................ 2
THE SCHEMATIC DIAGRAM AND IN THE PARTS Service procedures llllllllllllllllllllllll 2
LIST ARE CRITICAL FOR RISK OF FIRE AND Exploded View ........................... 4
ELECTRIC SHOCK. REPLACE THESE COMPO- Parts list _____________________________ 5
NENTS WITH ONKYO PARTS WHOSE PARTS Circuit descriptions ......................... 6
NUMBERS APPEAR AS SHOWN IN THIS MANUAL 1C bIock diagram ......................... 2
Block diagram ........................... 17
MAKE LEAKAGE'CURRENT OR RESISTANCE Adjustment procedures ..................... 18
MEASUREMENTS TO DETERMINE THAT EXv Pc board view
POSED PARTS ARE ACCEPTABLY INSULATED Main circuit ............................ 21
FROM THE SUPPLY CIRCUIT BEFORE RETURN» Digital/Display circuit ____________________ 25
INC THE APPLIANCE TO THE CUSTOMER Switch pc boards ........................ 27
Pc board-parts list ......................... 23
Packing View ............................ 28

ONKYo i
IIIIIIIII IIIIIIIPIIIIIIIISJi

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SPECIFICATIONS

Tuning Range:

87.5 ,, 108.0MHZ
(AUTO MODE SOkHz steps,
MANUAL MODE ZSkHZ steps)

AM Suppression Ratio:

Total Harmonic Distortion:

60dB
Mono: 0.009% (IF: wide)
Stereo: 0.02% (IF: Wide)

Usable Sensitivity: Mono: 0,8irV (S/N 26dB, 40kHz Frequency Response: 30 - 15,000Hz (+0.5dB, -1.0dB)
Dev.) DIN Stereo Separation: 55dB at lkHz (IF: wide)
Stereo: ZOAOuV, (S/N 46dB, 33dB at 70 - 10,000Hz (IF: wide)
40kHz Dev.) DIN Output Voltage: 0 - 1.5V
SOdB Quieting Sensitivity: Mono: 15,8dBf, 1.7uV Dimensions (W X H X D): 465 X 103 X 387mm
Stereo: 37.2dBf, 20uV 18-5/16 X 44/16" X 15-1/4
Capture Ratio: 1.0dB Weight: 8,5kg, 18.71135.
Image Rejection Ratio: lOOdB
IF Rejection Ratio: 100dB Specifications and features are subject to change without notice.
Signal-tovNoise Ratio: Mono: 95dB (IHF)
Stereo: SSdB (II-IF)
Selectivity: SOdB (2 300kI-Iz, IF: super
narrow)

SERVICE PROCEDURES

1. Replacing the lamp
This unit uses the lamp listed below.
Circuit no. Parts not Desciption
0754 210064A PL 6.3V, 250mA, Dial
plate illumination

2. Memory Preservation

This unit does not require memory preservation bat-
teries, A built-in memory power backup system preser-
ves contents of the memory during power failures and
even when the unit is unplugged. The unit must be plug-
ged 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 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. 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 ofif. This period is shorter when
the unit is exposed to very high humidity or used in an
area with an extremely humid climate.

Page 3

3. Procedures for replacement of flat packaged ICs

1. Tools to be used:

(1) Soldering iron . . .. Grounded soldering iron or
soldering iron with leak re-
sistance of 10 Mohms or
more.

Form of soldering irons tip:

(2) Magnifying glass . .. for checking of finished

works

(3) Tweezers ........ for handling of 1C and
forming of leads

(4) Grounding ring . . . . Countermeasure for electro-
static breakdown

(5) Nipper ......... for removing defective IC

(6) Small brush ...... for application of flux

2. Work Procedures:

(1) Remove the defective lC
Cut all leads of the defective IC one by one using
a nipper and remove the IC.

(2) Clean the pattern surface of the PC board.
Get rid of the remaining leads and solder.

(3) Check and from the leads of the new flat pack-
aged lC to be installed.
From every lead on the new [C using a pair of
tweezers, so that all of them are aligned neatly
without being risen, twisted or inclined toward
one side Especially the rising portion of every
lead must be formed with greatest care.

g K: g Ic E Ic //
\
(Rising) (Twrsringl llnclining)

Fig. 2

(4) Apply flux to the PC board.

Apply flux to the pattern surface of the PC board
which has been cleaned, as shown in the illustration.
The area to be applied with flux is the portion of
about 2.5mm in width where the ICs leads are to
be soldered.

Be careful to apply minimum amount of flux
required so as not to smear it on unwanted areas.

ggg

About 25 mm
Fig. 3

(5)

(6)

(7)

T~)))ll

Temporarily tighten the 1C

Carefully align the pattern and lCs leads, so that
the IC will be temporarily tightened to the pattern
on the four leads at the corners, At this time, sol~
dering is required, but no need to apply soldering

Milli;

z:
3::
=1: :2:
:32: r:
m 3::
:2
=3:

will;

Apply flux to [CS leads

Apply flux to the areas of [CS leads where soldering
is to be performed. Be careful not to smear flux on
the root portion of any lead or the body of IC.

Apply flux only to
this portion.

Fig. 5

Soldering

While attaching the tip of the soldering iron to the
soldering point as shown in the illustration, feed 2
-5mm of soldering wire, Then, slowly move the
iron in the direction indicated by the arrow in the
illustration, so that the leads will be soldered to
the pattern. Move the iron in the rate of approxi-
mately 1cm in Ssec. Proceed with your work
while confirming a clean fillet of solder is formed
on each lead, subsequent to the melting of flux.

Soldering Wire

Fig. 6

Soldering Iron

CAUTION

1)
2)

(8)

If you move the iron too quickly, loose soldering is
likely to result.

Be especially careful when soldering the first lead
where loose soldering is most liable to be formed.
Check the results

When soldering of all leads is finished, check the
soldered portion on every lead with a magnifying
glass. A tester must not be used or checking of
any soldered position

Page 7

3. IF band selection cyircuit

T-WNH

At the A/D input signal pin 63 of 0710, when the SD
terminal goes low, automatically the IF band is determined.
At the time of NARROW selection, the output of pin
10 goes H, and at the time of SUPER NARROW, pin
11 goes H. In 0728, at the band selection switch, pins
1, 2, and 7 respectively go high for WIDE, NARROW,

and SUPER NARROW.

- Wide operation -

0722 and 0723 go ON, the collector voltage of 0723
becomes essentially +132, D103, D104, and D106 go ON,
and the IF signal passes through D103, D104. and D106.

4. Stereo switch circuit

MONO AUTO
Micon $
Pin 13
0302
[3 STEREO
n
1' 792, ozcooen ,,

.rwm A MONO L
Muhnq
Civzuit

When a stereo broadcast is received, pin 12 of 0302 goes
L", 0303 goes ON, the collector voltage becomes H,
and the stereo indicator lights. Also, pins 5 ans 6 of the
0306 analog switch go H, conduction occurs between
3N4 pins and 8~9 pins, and at the 0302 stereo decoder,
the L and R divided signal is output. In addition, at the

STEREO

STE RE

DHIDH2
SUPER NARROW lF AMP eta
5
5 7*) TO PLL
E ' 0101 lo 6"
é wa IF 14°qu NARROW £5 w," ,F u o a
AMP IF AMP Aw: _ ,"V'
K I:
z NARRow 0724 , 0725 NARROW H DHO mos 0M)
2 GATE CtRCUlT mos 0:04 0.06
5 w I thE 0722,0723 WIDE H 0305 6
E g GATE moon 1 1:
w
E 2m 7 SN 0726,0727 supsa NARROWH" V 5% Y K
c 0 E GATE cmch 3 at; mi, 3
K m 8 c
K U
g 1. 5'
. 7 3 w
0307
0305
(Fig. 11)

- Narrow operation

0724 and 0725 go ON. D102, D101, and D105 go ON,
and the IF signal passes through NARROW amplifier
0104. Also, at the time of WIDE, in order to change
to maximum operation, 0308 and 0310 are turned ON,
and with R305, compensation of operation is carried out.

7 Super Narrow operation -

0726 and 0727 turn ON, D111 and D112 diodes go
ON, and the signal passed through the super narrow IF
amplifier is output in the PLL detector circuit. Also,
for the alignment of narrow, 0307 and 0309 go ON,
and separation is compensated by R304.

STEREO _l
L MONO R

in am
>-_ its
Lo
:13
u
on
p
Z
in
it?
O
C]

STEREO

-67v

(Fig. 12)

time of monaural broadcast reception, and when the
MODE switch is in the MONO position, pin 12 goes H,
and because 0303 and 0304 are in the cutoff condition,
pins 12 and 13 of 0306 go to high level, conduction
takes place between pins 10~ll and 1~2, and the detected
signal passes through the AF amplifier to be output.

,7,.