Sony SEQ-555ES User manual

SERVICE MANUAL
Inputs
Refer to RM-31 Service Manual issued previously for
information of remote commander supplied with this set.
US Model
Canadian Model
AEP Model
E Model
SPECIFICATIONS
(0dBs =0.775V)
level
LINE IN ~10dBs (245 mV)
AUX 1,2 | -10dBs (245 mV)
ie Reference input Input
: Connector
impedance erineet
Low ae?
impedance
50 kohms Phono jack
50 kohms Phono jack
50 kohms
TAPE 1, 2 | —10dBs (245 mV)
Phono jack
Outputs
(0dBs
=
0.775V)
Reference
|
Max.
output
|
Load
im-
output
Connector
level
pedance
level
LINE
-10dBs
+19dBs
;
|
out
(245
mV)
[91
V)
50
kohms
|
Phono
jack
REC
OUT/-10dBs
+19dBs
:
1,2
(245
mV)
(6.91)
50
kohms
|
Phono
jack
Frequency response MIC: Adjusted according to the supplied
microphone
LINE: 10 Hz- 100 kHz *3dB
Total harmonic distortion
LINE: Less than 0.006% (1 V output,
1 kHz)
Signal-to-noise ratio LINE: More than 97 dB (A network, flat,
1V output)
Center frequencies 31.5Hz, 63Hz, 125Hz, 250 Hz, 500 Hz,
1kHz, 2kH
(for both g
analyzer)
Adjustable range
+12dB (2d
z, 4kHz, 8kHz, 16 kHz
raphic equalizer and spectrum
L, Ror L+R
B step), +6dB (1dB step)
adjustable
Frequency
response reverse function
(CHARACTER button)
Gain 0dB
Level adjustable range (at manu
TTT One ton
Pra hay
|]
MICROFILM
al operation)
Automatic sound field adjustment
Measuring level: About 74dB SPL
(at microphone position)
Measuring time: About 2 seconds for
each channel after level reaches the
measurable level
Number of measurements (averaged):
Max. 16 times
A: for rhythm music
B: for female vocal
C: for classical and mood music
FLAT: 0dB (flat response)
Fixed memories
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK
A ON THE SCHEMATIC DIAGRAMS, EXPLODED
VIEWS 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
PUBLISHED BY SONY.
ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE TRAME ET
UNE MARQUE /\ SUR LES DIAGRAMMES SCHE-
MATIQUES, LES VUES EXPLOSEES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER CES
COMPOSANTS QUE PAR DES PIECES SONY DONT
LES NUMEROS SONT DONNES DANS CE MANUEL
OU DANS LES SUPPLEMENTS PUBLIES PAR SONY.
PROGRAM EQUALIZER
SONY.

SEQ-555ES
General
Power
requirement
120
or
240
V
ac,
adjustable,
50/60
Hz
(AEP,
E
model)
120 V ac, 60 Hz (US, Canadian model)
Power consumption 25 watts
AC outlets (US, Canadian only)
2 switched, 450 watts max.
1 unswitched, 450 watts max.
Dimensions
Approx.
430
x
105
x
275
mm
(wi/h/d)
(17
x
4Y,
x
107,
inches)
including projecting parts and
controls
Weight Approx. 5.2kg (11 1b 802)
Approx. 6.5kg (141b 502) in shipping
carton
FEATURES
The SEQ-555ES program equalizer is a system control
center that provides you with maximum enjoyment from
the world of audio-video presented by digital audio
sources such as CD (Compact Disc) and PCM (Pulse
Code Modulation), and by Hi-fi video. It also works as an
ordinary graphic equalizer, allowing you to create your
own original sound.
System selector for the AV era
Enriched input/output terminals, in line with the develop-
ment of systems connected with AV (Audio-Video)
units *, characterized by clear image and excellent tone
quality, especially with a Hi-fi video unit connected.
Five input and three output channels, permitting signal
switching with the SEQ-555ES main unit or with the sup-
plied remote commander RM-31, are provided.
* As no video signal terminal is provided in the SEQ-555ES, it is not
possible to process the video signal.
Automatic equalization
The flat frequency response of the playback, including
the listening room and speaker, gives a reference for op-
timizing adjustment of each frequency band with the
equalizer.
In the SEQ-555ES, the sound field is measured and
analyzed by the built-in microprocessor combined with
the microphone, supplied especially for sound field
measurement. Adjustment inverse to the analysis result
is automatically carried out so that the frequency
response becomes flat at the measuring position.
Infrared remote commander
Each time adjustment is made by operating the equal-
izer switches and controls, the effect at the listening
position must be checked with the conventional graphic
equalizer.
However, ideally, adjustment should be carried out with
the listener actually at the listening position.
The RM-31 remote commander makes this possible. In
addition to on-band equalizer adjustment, it permits
on/off control of the power supply (US, Canadian), input
selection recall of memorized equalizer curves and sound
volume control.
Memory permitting immediate recall of equalization
As it is difficult to determine the most appropriate levels
of equalizer adjustment, four equalization curves of dif-
ferent types of music are stored in the fixed memory of
the SEQ-555ES. Each curve can be recalled by one-touch
operation of the corresponding key. Moreover, four
memories are provided for storing original curves made
by the user.
NOTES ON REPAIR
The frequency response of this set is adjusted to
match the microphone. Therefore, frequency re-
sponse adjustment is required when the microphone
is replaced. (Refer to page 23, Frequency Response
Adjustment.)
REPAIR CHECK POINTS
1. Before checking the microcomputers, be sure
that power supply voltage is being properly
applied and that the clock signal is being applied.
Also confirm that the reset pin is high.
Microcomputers A (IC751) and C (IC451) are
controlled by microcomputer B (1C501).
. Microcomputer A (IC751)
This microcomputer controls key input and re-
mote control input. It sends the data to micro-
computer B when there is key input or remote
control input.
Checking is performed as follows.
@ Data should be output at pin ay when the
power supply plug is pulled and then plugged
in again.
@ Pin (5) and (16) interrupt signals should be
generated when any key is pressed.
@ A microcomputer clock signal (4.19MHz)
should be being applied to pin(7).
® Confirm that pins Q) — key scan signals
are being output’ (except for pins and @5)
@ Pin should be high level. When this pin is
low, the key scan signal is not output and key
input is not accepted.
@ Pins Q) _ (4) are for accepting key input, so
check that the key scan signal of any pin
appears when a key is pressed.
bo
—2—

3. Microcomputer C (IC451)
Microcomputer C controls LED display, and
should be checked when there are any abnormal-
ities in LED display.
@ Pins qd) - @) are input pins for data from
microcomputer B. Check that data is applied
to these pins when the power switch is turned
on and off.
@ Check that signals are being output from
output pins @) - :
4. Microcomputer B (IC501)
This contorls microcomputers A and C and other
IC’s. Therefore, this microcomputer should also be
checked when microcomputer A and/or C is
thought to be defective.
MODE
L IDENTIFICATION
— Specification Label —
SONY:
PROGRAM EQUALIZER
WLLL LLL
SEQ-555ES
MODEL NO.SEQ-555ES
US, Canadian model: 120V 60Hz 25W
AEP, E model: 120/220V ~ 50/60Hz 25W
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 0.5mA (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.
2. 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 0.75V, 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)
|
weary
Fig. A. Using an AC voltmeter to check AC leakage.
we
0.15 pF S154: voltmeter
(0.75 V)
_—
To Exposed Metal
Parts on Set
AC
Earth Ground
————__|

SEQ-555ES
LOCATION AND FUNCTION OF CONTROLS
Each number in the photo is keyed to descriptive text.
6
Front panel
FRONT PANEL
@ POWER switch
Press this switch to turn the power on.
Press it again to turn the power off.
@ EQ (equalizer) CHARACTER switch
Press this switch to invert “+” and ‘“—” of the equalizer
curve. When this switch is pressed, the built-in indicator
lights.
As a similar effect to the noise reduction system is ob-
tained, hiss noise can be reduced if this switch is used
at playback.
As tape hiss noise is a high frequency component, make
a curve which gradually rises from 4kHz and higher at
recording. When this switch is pressed in playback
mode, the curve is inverted to that at recording, and hiss
noise is reduced.
At recording At playback
Signal level ee Signal level
When
the
equalization
curve
is
inverted,
the
actual
fre-
quency
response
of
the
listening
point
is
displayed.
© EQ (equalizer) LEVEL selectors
These
buttons
select
the
equalizer
curve
level
adjusting
ranges.
+6
dB:
Fine
correction
in
1dB
steps.
When
this
button
is
pressed,
the
built-in
indicator
lights.
+12dB:
Correction
in
2dB
steps.
When
this
button
is
Pressed,
the
built-in
indicator
lights.
When
the
range
is
switched
to
+12dB
while
indication
is
in
the
+6dB
range,
—1dB
is
added
to
the
odd
setting
in
the
positive
(+)
and
the
negative
(—)
directions.
Wr migii Tigi Hida
<P 318 63128 250 800 1k 2k 4k ak Yk He ©?
+12 dB indication y
When a point over 8dB is included in the indication of
12
dB,
the
+6
dB
button
is
not
accepted
even
if
it
is
press-
ed, and the indicator built in the +6dB button blinks.
When the BEEP switch (rear panel) is ON, a beep tone is
emitted, notifying key-in operation is not accepted.
@ EQ (equalizer) MODE selectors
These buttons select the equalization modes: simul-
taneously in left and right channels, and separately.
L: Press this button to equalize the left channel inde-
pendently. The built-in indicator lights.
In the equalizer display, only the yellow indicators
are lit.
R: Press this button to equalize the right channel inde-
pendently. The built-in indicator lights.
Orly the red indicators are lit in the equalizer dis-
play.
—4—

L+R: Press this button to equalize left and right channels
simuitaneously at the same step.
The built-in indicator lights. In the equalizer display,
both yellow (left channel) and red (right channel)
indicators are lit.
@ UP/DOWN (equalizer level adjust) buttons
These buttons correct each frequency band of the
graphic equalizer display.
@ Graphic equalizer display
This indicates the curves of automatic equalization and
adjustment with the equalizer. The yellow indicator
shows the left channel level, and the red the right chan-
nel level. One graduation is 1dB when the +6dB button
of EQ LEVEL selector is being pressed, and 2dB when
the +12dB button is being pressed.
@ LEVEL indicator
This shows the output level of the LINE OUT jacks.
Usually, set so that all the indicators are lit (dB gain).
This shows the sound volume when the SEQ-555ES is
used as an audio system selector.
© AEQ (automatic equalization) indicator
This indicator blinks when the level is too low in the
sound field measurement and a signal of 1kHz does not
reach the —5dB white line. In this case, increase the
amplifier volume gradually so that the signal ap-
proaches the white line.
This indicator remains lit for one minute after the sound
field is measured by pressing the START button.
If the START button is pressed again while this indicator
is lit, the value averaged with the last measurement is
input as a data.
© REAL TIME ANALYZER display
This is a 10-division real time analyzer, and the frequen-
cy band is the same as that of the graphic equalizer. It
indicates the acoustic energy of sound field picked up
by the microphone at sound field correction, and the
acoustic energy of left and right channels of program
source at adjustment with the equalizer.
The —5dB white line (thick line) shows the optimum level
at equalization. For music playback, an environment
where the external noise measured at sound field correc-
tion is lower than —5dB is required.
@ FIXED MEMORY keys
These keys access the equalization curves for three
kinds of music memorized. When the key is pressed, the
corresponding built-in indicator fights.
A: Effective for jazz and rock
B: Effective for female vocal
C: Effective for classical and mood music
FLAT: The equalizer frequency response becomes flat.
@ INPUT SELECTOR buttons
These buttons select the input required.
The indicator of the pressed button lights.
SEQ-555ES
SEQ-555ES
LINE: Press this button to listen to the program source
selected by the amplifier connected to the LINE IN
jacks.
AUX 1, 2: Press these buttons to listen to the program
source connected to AUX 1 and 2 jacks.
TAPE 1: Press this button to listen to the tape deck
connected to the TAPE 1 jacks.
TAPE 2: Press this button to listen to the tape deck
connected to the TAPE 2 jacks.
@® EQUALIZATION selector keys
These keys select the output to be equalized.
The indicator of the pressed key lights.
AEQ: Press this key to carry out equalizer adjustment
after adjustment of sound field.
Press the AEQ key for normal playback through
speakers.
LINE OUT: Press this key to equalize the program source
to be listened to.
As sound field correction is not added, press the
LINE OUT button for playback through headphones
or for comparing two pairs of speakers.
OFF: Press this key when making no equalization.
When the OFF key is pressed, the indicator and
graphic equalizer display related to the equalization
go out.
REC OUT: Press this key to equalize only the signal to be
recorded, without equalizing the current program
_ source. Press the REC OUT key, and select the pro-
gram source to be recorded by pressing the cor-
responding button of the REC OUT SELECTOR.
® REMOTE SENSOR
The infrared beam transmitted by the supplied remote
commander is received here.
@® Remote control signal indicator
This lights when the power cord is connected to a wall
outlet, indicating the unit is ready to accept the remote
control signal. It goes out when the POWER switch is
pressed to turn on. It lights when the remote control
signal is received.
@® MEMORY keys
Press these keys to memorize the equalization curves.
SET: Press this key after the equalization curve to be
memorized is determined. The built-in indicator
lights for a few seconds. Memorize the curve during
this period by pressing the corresponding [1] - [4}
keys.
[4]: Press these keys to memorize the required
equalization curve, or recall the memorized curve.
@ REC OUT SELECTOR buttons
These buttons select the program source applied to the
REC OUT jacks on the rear panel.
LINE OUT: Press this button to record the current sound
as it is.
LINE: Press this button to record the source selected by
the amplifier connected to the LINE IN jacks.
—5—
AUX
1,
2:
Press
this
button
to
record
from
the
program
source
connected
to
the
AUX
jacks.
TAPE
1
—
2:
Press
this
button
to
copy
from
tape
deck
1
to
tape
deck
2.
TAPE
2
—
1:
Press
this
button
to
copy
from
tape
deck
2
to tape
deck
1.
@® AUTO EQ MIC jack (minijack)
Connect
the
supplied
microphone
for
sound
field
meas-
uring to this jack.
Rear panel
The photo shows type 2 model.
(41) 21 mm Ob @
REAR PANEL
@ LINE IN jacks
Connect these jacks to the tape output jacks of the
amplifier.
@ LINE OUT jacks
Connect these jacks to the tape input jacks of the
amplifier.
@ AUX 1, 2 (auxiliary 1, 2) jacks
Connect these jacks to the audio output jacks of a CD
player, etc.
@ TAPE RECORDER 1 REC OUT jacks
When only one tape deck is connected for recording,
connect these jacks to the fine input jacks of the deck.
@ TAPE RECORDER 1 TAPE jacks
When only one tape deck is connected for playback, con-
nect these jacks to the line output jacks of the deck.
To play a Hi-fi video, connect these jacks to the audio
line output jacks of the video.
@ TAPE RECORDER 2 REC OUT jacks
When two tape decks are connected for recording in the
second deck, connect these jacks to the line input jacks
of the deck.
@ TAPE RECORDER 2 TAPE jacks
When two tape decks are connected for playing in the
second deck, connect these jacks to the line output
jacks of the deck.
@® AUTO EQ START button
Press this button to generate a pink noise from the built-
in pink noise generator for sound field adjustment. When
the sound field measuring microphone is connected,
this button can be actuated. The pink noise is radiated
from the left channel speaker, and then the right channel
speaker. This pink noise is picked up by the microphone
and input as a sound field data.
@® Level UP/DOWN button
When the SEQ-555ES is used as a system selector, this
button is used for volume adjustment. The amplifier
volume should be set to an attenuation of 20-30dB.
27 (4)
@ BEEP (remote control signal) switch
When this switch is set to the ON position, a beep tone
is emitted when the button of the supplied remote com-
mander is pressed. If a point of over 8dB is included in
the indication of +12dB, switching to +6dB is not ac-
cepted and the beep tone is generated even if the +6dB
button is pressed. Set this switch to the OFF position
when the beep tone is unnecessary.
@ AC OUTLETS (US, Canadian only)
These outlets are used for connecting the power cords
of compact disc player, tuner, tape deck and other pro-
gram sources. When the power cord of the equipment to
be connected has a white mark indicating the polarity,
connect the power cord so that the white mark comes to
the left side of the outlet.
SWITCHED: This outlet interlocks with the POWER
switch of the program equalizer: the power on/off of
the connected equipment can be controlled by the
POWER switch of the program equalizer, when the
power switch of the connected equipment is set to
ON.
This is convenient when the program source to be
played frequently is connected to this outlet. The
total power consumption is 450W.
UNSWITCHED: This outlet provides power irrespective
of whether the POWER switch of the program
equalizer is ON or OFF. Connect equipment with a
power consumption of 450W maximum to this
outlet.
@ Power cord
—6§—
AUTO
ADJU
& &
a
7
(HHo
Press
and &
Set t
than
Conn
Place
Press
Pir
sys
inc
red
cat
2s
rig
Even
main
After
butto
Repe
Each tin
cessor
measure
Press th
data.

Q-555ES
SEQ-555ES
n source
LINE IN
program
ipe deck
ipe deck
justment
through
n source
ress the
dphones
on.
ator and
alization
nal to be
program
the pro-
the cor-
TOR.
1 remote
iO a wall
2 remote
witch is
» control
curves.
ve to be
ndicator
e during
g 4) - (4)
required
| curve.
2d to the
it sound
ected by
KS.
AUX 1, 2: Press this button to record from the program
source connected to the AUX jacks.
TAPE 1 — 2: Press this button to copy from tape deck 1
to tape deck 2.
TAPE 2 — 1: Press this button to copy from tape deck 2
to tape deck 1.
@® AUTO EQ MIC jack (minijack)
Connect the supplied microphone for sound field meas-
uring to this jack.
Rear panel
The photo shows type 2 model.
@® AUTO EQ START button
Press this button to generate a pink noise from the built-
in pink noise generator for sound field adjustment. When
the sound field measuring microphone is connected,
this button can be actuated. The pink noise is radiated
from the left channel speaker, and then the right channel
speaker. This pink noise is picked up by the microphone
and input as a sound field data.
@® Level UP/DOWN button
When the SEQ-555ES is used as a system selector, this
button is used for volume adjustment. The amplifier
volume should be set to an attenuation of 20-30dB.
REAR PANEL
@ LINE IN jacks
Connect these jacks to the tape output jacks of the
amplifier.
@ LINE OUT jacks
Connect these jacks to the tape input jacks of the
amplifier.
@ AUX 1, 2 (auxiliary 1, 2) jacks
Connect these jacks to the audio output jacks of a CD
player, etc.
& TAPE RECORDER 1 REC OUT jacks
When only one tape deck is connected for recording,
connect these jacks to the tine input jacks of the deck.
@ TAPE RECORDER 1 TAPE jacks
When only one tape deck is connected for playback, con-
nect these jacks to the line output jacks of the deck.
To play a Hi-fi video, connect these jacks to the audio
line output jacks of the video.
@® TAPE RECORDER 2 REC OUT jacks
When two tape decks are connected for recording in the
second deck, connect these jacks to the line input jacks
of the deck.
@ TAPE RECORDER 2 TAPE jacks
When two tape decks are connected for playing in the
second deck, connect these jacks to the fine output
jacks of the deck.
@ BEEP (remote control signal) switch
When this switch is set to the ON position, a beep tone
is emitted when the button of the supplied remote com-
mander is pressed. If a point of over 8dB is included in
the indication of +12dB, switching to +6dB is not ac-
cepted and the beep tone is generated even if the +6dB
button is pressed. Set this switch to the OFF position
when the beep tone is unnecessary.
@ AC OUTLETS (US, Canadian only)
These outlets are used for connecting the power cords
of compact disc player, tuner, tape deck and other pro-
gram sources. When the power cord of the equipment to
be connected has a white mark indicating the polarity,
connect the power cord so that the white mark comes to
the left side of the outlet.
SWITCHED: This outlet interlocks with the POWER
switch of the program equalizer: the power on/off of
the connected equipment can be controlled by the
POWER switch of the program equalizer, when the
power switch of the connected equipment is set to
ON.
This is convenient when the program source to be
played frequently is connected to this outlet. The
total power consumption is 450W.
UNSWITCHED: This outlet provides power irrespective
of whether the POWER switch of the program
equalizer is ON or OFF. Connect equipment with a
power consumption of 450W maximum to this
outlet.
@ Power cord
—6—
AUTOMATIC SOUND FIELD
ADJUSTMENT
Amplifier
ee
| @-- 000+ 0 6!
AEQ indicator
1 Press the POWER switches of the program equalizer
and amplifier.
2 Set the volume level of the amplifier slightly higher
than that for normal listening.
Connect the microphone to the MIC jack.
Place the microphone at your listening position.
5 Press the START button.
Pink noise is first emitted from the left speaker
system and its level gradually increases. The AEQ
indicator flickers. When the pink noise level
reaches the reference level of -5dB, the AEQ indi-
cator steadily lights and noise is emitted for about
2 seconds. Then, pink noise is emitted from the
right speaker system for about 2 seconds.
6 Even when pink noise stops, the AEQ indicator re-
mains lit for about 1 minute.
After the AEQ indicator goes out, press the START
button again.
7 Repeat step 6 at least once more.
mw
Each time the data is obtained, the built-in micropro-
cessor analyzes, compensates and memorizes the
measured data.
Press the AEQ key to recall the compensated sound field
data.
SEQ-555ES
The graphic equalizer display indicates the sound field
adjustment curve at the place at which the microphone
is placed. After second adjustment, the measured data
is added with the previous data.
To carry out automatic sound field adjustment effec-
tively, obtain the data at least 3 times at the same posi-
tion.
Data can be compensated and measured up to 16 times.
More than 16 measurements cannot be accessed while
the AEQ indicator remains lit. To resume adjustment,
wait until the AEQ indicator goes off or turn the power
off and on again.
When automatic sound field adjustment is completed,
return the amplifier volume contro! to the normal listen-
ing position.
To observe the actual sound characteristics at your
listening position
Press the CHARACTER button. The equalization curve is
inverted to display the actual sound characteristics at
your listening position. With this operation, you can see
the sound characteristics of the audio system and
listening room.
Notes
@ Be sure to carry out automatic sound field adjustment
before playing back the sound source. If the START but-
ton is pressed while playing the sound source, the
acoustic energy remaining from the played sound
source is added to the pink noise and correct sound field
adjustment is not possible.
@ When the level of the emitted pink noise is insuffi-
cient, the AEQ indicator remains flickering. In this case,
increase the amplifier volume level.

SEQ-555ES
1-1.
SECTION 1
OUTLINE
BLOCK DIAGRAM
CNJ353~3
@
TAPE |
CNJ354-3 iC
TAPE2
(7) TAPE| INPUT REC OUTPUT 1(8)
(6) TAPE 2 INPUT REC OUTPUT 2(9)
CNU35I~1 e
LINE IN
(2)
LINE
INPUT
LINE
OUTPUT(1O)
CNJ352~1
AUXI
CNU352-3
AUX2
(4) AUX! INPUT
(3) AUX2 INPUT
FUNCTION SWITCH
1C 351
J301
mo
(3)
MIC
AMP
(1)
iC 201
SEQ-555ES
(5)
LINE
AMP
(7)
(14)
LINE/PINK NOISE SELECT
LINE/PINK NOISE
Dao, (setter)
<8 >
STEP
(2) (2) VOLUME @)
1C 103
SV 0116 LINE MUTE
CD
8-
(r\ alle
) LINE MUTE
Qt
LINE MUTE
B+
9102 switcHING Quis ila
LINE MUTE
IC
101
1c
102¢172)
Pp-o—
PINK
NOISE
CH
Osc
EQ
AMP
(i)
3)
£0
amp
(@)
1C102
(1/2)
10106
se
10105
SWITCHING
LINE
PINK
NOISE)
(IE
@108
SWITCHING
EO
VOLUME
(LINEZEINK
Novse)
1108
—
112
de.
TON
BEEEET,
SWITCHING
C?
SWITCHING
RESONANCE
CIRCUIT
(LEVEL)
5
peaicyeaioes
Ic
107
NSELECT
ay
7
4
ey
9109
SWITCHING
(LEVEL
)
SELECT
aior
sp
ING
ray,
SN
(LD
MUTING
$|—47 , 701 — 707
(POWER, FUNCTION SWITCH, OTHER}
0401
REMOTE SENSER
REMOTE
CONTROL
PRE AMP
1C40t
»
BANDPASS
LOGARITHM
(2)
EQ
AMP
(1)
ae
RECT
MULTI
PLEXER
AMP
1518
1c513—518
Ic519—523
ie
soe
6
Q105 ——gi04 \e;
SWITCHING
(LINE/MIC
SELECT),
Q5i2
D MICRO COMPUTER
1505
INPUT/OUTPUT
PORT F
Ch (INVERTER)
My,
|
1C508, 509
Q513
LCD MUTE (j~
A/D
CONVERTER
1C507
(IO)SENS INPUT $
05
OUTPUT PORT 0
08
A MICRO COMPUTER
CLOCK OSC
1504 (1/2)
T501
04(2) (2)
SEQ-55
QUT
Nt QlI9 REC MUTE
Qus
REC
MUTE
= Q120
7 REC
MUTE
BUFFER
AMP
(I) MULTI PLEXER
Ie510(1/2)
1c512
VOL.R
Q30%
DECODER
C MICRO COMPUTER (20 10.456
1451
(1) 39
(2)
|
DECODER
INDICE
458
(BUZZER)
8
41
Ic
Ic4
(S) 26
(16)
|
DECODER
INDICE
RESET
SWITCHING
RESET
—
29
1454
ICé
esoatiey | RESET extar
if
TO
MICRO
COMPUTER
gy
VOL.R
SECTION 522!
“ { VOL.R
Q5i9 B+ :
switching RYSO! 9301,
TO ANALOG
WOL.
REG,
ON
e+
TO MICRO COMPUTER
SECTION
B+
POWER TRANSFORMER
VOL. REG, RECT
Q5i7,518 0533
3
Hs

SEQ-555ES
SEQ-555ES
. (5) LINE AMP (7)
{C 10t
LINE/PINK NOISE SELECT
1€ 1021/2)
PINK
NOISE
“LT
SPV
TSSEINE
MUTE
ry)
aie
osc
aA)
AJ,
ws
LINE
MUTE
1C10211/2)
nibs
SWITCHING
B-
(LINEZPINK
No¥S
SELECT
ani
LINE
MUTE
B+
9108
‘>
EQ
VOLUME
STLINEY
PINK.
NOISE
Q102
—
switcHine
Quis
Qiia
on
my
SELECT
)
LINE/PINK
NOISE
LINE
MUTE
1C
108
—
Il2
-_
)
SELECT
aa
‘A101
SWITCHING
SWITCHING
S
LEVEL
iene
C107
SELECT)
:
SD
i
@
7
et]
0109
SWITCHING
(SEVEN)
8)
SELECT
O07
Cp
ray,
D
MICRO
COMPUTER
@.
{
6
~
1C505
INPUT/OUTPUT
Q105
Q104
unl)
PORT
F
SWITCHING
(LINE/MIC
SELECT).
Q5le
SWITCHING
(INVERTER)
ay
BANDPASS
LOGARITHM
A/D
BUFFER
(2)
£0
AMP
(1)
FILTER
RECT
MULTI
PLEXER
AMP
CONVERTER
(I0)SENS
INPUTS
042)
AMP
1C518
1C513—
518
C519
—523
1508,
509
16506
1c
507
Q513
Ps
LCD MUTE (97
9
A MICRO COMPUTER
RAM We
—
1c502 09
f\
BZ501
(BUZZER)
RESET SWITCHING
Q516 Q5i4
}
C MICRO COMPUTER
RESET
1C504(1/2)
CLOCK OSC
1€504 (1/2)
B+
VOL. REG,
Q521
TO MICRO COMPUTER
SECTION
B+
TSOH
POWER TRANSFORMER
TO MICRO COMPUTER
SECTION B+
Q519 RY501 B+
o520 SWITCHING
SWITCHING
SWITCHING 79 ANALOG
(RESET) | =
(2) @ 6
1C503 i
I 8-
IC510(1/2)
CNBC!
REC OUTI
SWITCHING
REC
OUT}
© _cNu351~4
10353
REC
OUT2
gj) cN381-3
LINE OUT
QUIZ
a Gig REC MUTE
oy
e~ oO
QHge
REC
MUTE
ne Q120
8 REC
MUTE
LCD DRIVE
C5172)
LCO DRIVE
ICS1O{1 72)
LCD DRIVE
IC5I(/2)
MULTI PLEXER
1C512
INDICATOR DRIVE
1C455, 457
VOL REG,
0303, 304
LED
INDICATOR
T80l
POWER TRANSFORMER
AC
IN

SEQ-555ES
SECTION 2
CIRCUIT DESCRIPTION
CIRCUIT DESCRIPTION 11 bit Control Data Structure
This model employs 4 microcomputers, to control 11 10 3 2 1
9 8 7 6 5 4
automatic acoustic compensation and frequency rs oe
equalizer adjustment, etc. F3 TaN data
The operation of each section is described below.
bit : ;
INPUT SECTION position : =| | position LD ee
6 5 3 2 1
IC 351,352 (CX-7977 are used for input source (LINE :
IN, AUX, etc.) selection. SS 0 SO ee | 20 PE
These IC’s are controlled by data from the micro- L D2) ome Rs “0; 3 IZ jo 0 1
computers. R 1 0} joutputE? }1 0 ae | eee
Their functions and features are explained below. L+R !/1- 1] | output F: 1 1 I, |0 1 1
2 4
CX-7977
Ir
/1
0
0O
Features:
This
is
a
semiconductor
switch
with
low
Ie
}1
O
1
distortion ratio containing two matrix
circuits with 6 inputs and 3 outputs each,
and control by digital signals is possible.
Control is done by 11 bit or 8 bit serial
data from a microcomputer, etc. and on
this model it is performed by 11 bit data.
F, and F3 outputs are interlocked, and Is input
signal is not output from F2.
Ig input signal is not output from F3.
Both L and R channels can be used with this ASP IC,
but on this model, L and R use one each, and the
Functions: equalizer ON/OFF matrix is formed.
I~6 (@~@, @~ @) Audio signal input pin On this model the connections are as follows.
(6 inputs ) x 2 I, LINE IN F
F,~3(®~ @, @~@) Audio signal output pin I, AUX, Fig to equalizer circuit
(3 outputs) x 2 input
CS (@) _— Signal chip selection pin, I; AUX, F, REC OUTi
selects when the 9th bit of Iq from equalizer F3; REC OUT2
serial data is the same level circuit output
as the CS pin. I; TAPE2 F,, to buffer amp
“QO” = Vss (@), Ig TAPE1
“1” OPEN or Vpi ( 4 )
M/S (4) Serial data input mode
switch pin, 11 bits for
OPEN or VoL.
Vo. (G3) Power supply (5V_ higher
than Vss)
Vss (@)) Power supply (-14V)
Clock (4) Clock signal input pin;
takes in data at signal rise.
Data (46) Serial data input pin.
Strobe (G7) Strobe signal input pin;
latches data taken into the
IC.
Lvref (48) Sets control signal (clock,
data, strobe) input level.
Von (@9) Power supply (+14V).
input
input
output
output
Data taken into the IC is input serially from the MSB
(most significant bit).
The data is taken into the IC shift register at signal
rise, the clock signal is stopped after input, the strobe
signal pulse rises and data is transmitted to the latch.
The contents of the data determine which switch goes
on or off.
—1 1—

SEQ-555ES
to equalizer circuit
Sg switch
LINE IN
AUX,
AUX,
from equalizer
circuit
TAPE2
TAPE]
to LINE OUT
REC OUT2
REC OUT1
F, and F3 are interlocked.
EQUALIZER CIRCUIT
ICios
Ry20 13k
Crip 220P
controlled by
microcomputer
Cros
CX-7976
resonance
circuit
63H2
resonance
circuit
31.5Hz
The equalizer circuit is structured as shown in the
above diagram, and actually, four IC’s are connected
parallel to ICj93 and determine the frequencies.
These IC’s are controlled by microcomputer.
In the example above, many switches and resistors
are connected inside ICj9g, and because it is con-
nected to the resonance circuits via these resistors,
and the NF circuit is connected to these resonance
circuits when it is on the UP side, the frequency
component output gain becomes high. When DOWN,
these resonance circuits connect to the attenuation
circuit, so the frequency component gain drops.
ICiog is controlled by microcomputer, and depending
on the data sent from the microcomputer, can
control only Q; or Qz, or both.
The equalizer frequency is controlled by these combi-
nations.
+6dB or +12dB switching is done by ICj97. When
ICjo7 internal switch is off, it is +12dB, and +6dB
when on.
CX-7976
Features: This is a 2 channel independent variable
2dB step electronic volume for low dis-
tortion equalizer, containing two circuits
which can obtain +12dB attentuation.
Control is done by 11 bit serial data from
a microcomputer, etc.
Functions:
Qi. (@, @, &, @ ) These pins are connected to L
and R_ channel resonance
circuits.
UP (@, @ ) Connected to op amp invert-
ed input.
DOWN (@, @) Connected to op amp non-
inverted input.
Serial data bits 9, 10 and 11
are all selected at the same
time as pins CS,,2,3 level.
“<Q” = Vss
“1”? = OPEN or Voi
CSi,2,3 (©, ©, @)
VDL (@) Power supply (5V higher than
Vss).
Vss (@) Power supply (-14V).
CLOCK ( @) Clock signal input pin.
Data (dad) Serial data input pin.
Strobe (@) Latches data taken into the
IC at signal rise.
Lyref (4) Sets control signal (clock,
data, strobe) input level.
Vpp (@) Power supply (+14V).
The 11 bit serial control data is input to the IC from
the MSB (most significant bit).
Data is taken into the IC shift register at clock signal
rise.
After data is taken in, the clock signal is stopped,
and the strobe signal rises. The strobe signal transmits
the data to the latch, and the data contents determine
which switch is turned on or off.