Technics SH-8075 User manual

|
\*
i The Bleek. type model is ‘indicated by (K)
in the Service Manual.
The colors of this model | 1S black type only.
"Naseperoctumsateleotinmnctoaity cman a peta in ss He aces
Specifications
(DIN 45 500)
Frequency response
(center position)
Maximum output
voltage
Rated output voltage
Rated total harmonic
distortion
Input sensitivity
Signal-to-noise ratio
Maximum input
voltage
input impedance
Output impedance
Gain
Channel balance
250 Hz~6300 Hz
Channel separation
1 kHz
Band level controis
>5 HZ~100 kHz, —1 dB
>8V (1 kHz, THD 0.01%)
(LOW LEVEL 150 mV)
ames
> 0.001% (20 Hz~20 kHz)
a
110 dB (120 dB, IHF ‘A)/2 V
104 dB (114 dB, IHF ’A)/1 V
8 V (1 kHz)
(LOW LEVEL 150 mv)
> 47 kQ
> 600Q
>O0+1dB
=+0:506
:70dB
+12dB~-12dB
Stereo Graphic Equalizer
Specifications are subject to change without notice for further improvement.
Weights and dimensions shown are approximate.
Center frequency
ORDER NO. SD83072619C2
Areas
|, [EH], [EB],
* EK] is cAvailieal in United Kingdo
* [EF] is available in France.
*{EH] is available in Holland.
* (EB) is available in Belgium.
x [EGA] iS available in F, R. Germ
an
a
TOA 202. 25 AZ OV oases
40 Hz, 50 Hz, 63-H2,:80: Hz,
100:HZ,.125 Hz, 160 Hz, 200 Hz,
250 Hz.375-Hz, 400 Hz,.500 Hz,
630 Hz, 800 Hz, 1 KHz, 1.25 kHz,
16 KHz, 2 kHz; 2.5 KHZ, 3.15 kHz,
4 kHz, 5 KHz, 6.3 KHz, 8 KHz,
10 kHz, 12.5 KHz, 16 KHz, 20 kHz,
25 KHz
Variable equalizer
Center-frequency
controls (variable) > 20 Hz~ 400 Hz
Bandwidth controls(Q) :0.7~7
Band level controls
hie dB] 1208
GENERAL
Power supply > AC 110 V/120 V/220 V/240 V,
50 Hz/60 Hz
Power consumption > 34 W
Dimensions
(33 elements continuously variable
per channel)
Signal level selector 7150 mV/1 V
& CONTENTS
Page
SAFETY:PRECAUTION 2p pei ee ERE Baws Seem 2
TOTAL FREQUENCY RESPONSE ii Bi ity Seah Gas Hes hae Cie SO aera ean
LOCATION OF CONTROLS . Sk WR ote lelctan Woe a Ae Ge
DISASSEMBLY INSTRUCTIONS . ; fay 8k ena a Oe
MODEL NO. SH-8065 BE DIFFERENT MODEL
NO. SH-8075 : : ews: &. pay “6
PRINTED CIRCUIT BOARDS WIRING.
CONNECTION DIAGRAM i a iat Bye
‘Technics
(HxWxD) > 153x430 x 330 mm
(6-1/32" « 16-15/16" x 13")
Weight : 6.6 kg (14.5 Ib)
Page
PRINTED CIRCUIT BOARDS .................. 9°16
TECHNICAL INFORMATION . ee ee ee eee |
EXPLODED VIEW....... le 18,19
REPLACEMENT PARTS LIST . Bi eae ole ee ea ee
SCHEMATIC DIAGRAM .............. 000-5. 21~30
BLOCK DIAGRAM ..... Say & bre & i oe SG eee
RESISTORS AND CAPACTIORS Pg yk he BB eA Hata ie, Op OA
Matsushita Electric Trading Co., Ltd.
P.O. Box 288, Central Osaka Japan

B SAFETY PRECAUTION
mf WN -
Wh - ©
_ Before servicing, unplug the power cord to prevent an electric shock.
. When replacing parts, use only manufacturer's recommended components for safety.
_ Check the condition of the power cord. Replace if wear or damage is evident.
.
After
servicing,
be
sure
to
restore
the
lead
dress,
insulation
barriers,
insulation
papers,
shields,
etc.
.
Before
returning
the
serviced
equipment
to
the
customer,
be
sure
to
make
the
following
insulation
resistance
test
to
prevent the customer from being exposed to a shock hazard.
INSULATION RESISTANCE TEST
.
Unptug
the
power
cord
and
short
the
two
prongs
of
the
plug
with
a
jumper
wire.
|
.
Turn
on the
power
switch.
.
Measure
the
resistance
value
with
ohmmeter
between
the
jumpered
AC
plug
and
each
exposed
metal
cabinet
part,
such
as
screwheads
antenna,
control
shafts,
handle
brackets,
etc.
Equipment
with
antenna
terminals
should
read
between
3M22
and
5.2MQ
to
all
exposed
parts.
(Fig.
A)
Equipment
without
antenna
terminals
meule
read
approximately
infinity
to
all
exposed
parts.
(Fig.
B}.
Note: Some exposed parts may be isolated from the chassis by design. These will read infinity:
Antenna
terminal
Exposed
metal part
Ohmmeter Ohmmeter’
(Fig. A) (Fig. B)
Resistance = 3M2 ~ 5.2M@Q Resistance = Approx OO
. 1f the measurement is outside “he specified ‘limits: there is a possibility of a shock hazard The equipment should be
saps and rechecked before it is returned to the customer. heed
@ TOTAL FREQUENCY RESPONSE
Frequency response (+12dB position}
+12
poeta ee ee ee alee die 2th
+10 PAAR RAO TAA UTA AA wa
<p PANINI LIE tee
oe CONES An
44 Ht AAR A AAU A A
“4215 LL A AX MARA SAX ee Nrenuniel
0
ee
SSS
2 RAAT OP I I IO ODI AY ALLA
— 4 DANO MAK KY MY TY IXY YI TY XIX KAY XX AL
VARY YY yYVV VV YY Vi 3 vuUW Uh
ed ori
a SOFA TA A
TA WUT LT A
“10 23. § 7100 2.3 § 71% 23 5710k 23 §
Frequency (H2)
Level a

SH-8075
@ LOCATION OF CONTROLS
Power switch
© Band ievel control
Equalizer on/of* switch
| B oft, = on}
Recording mode switch
{ Mf straight, = EQ)
tape 7
tase 2
@ Sand level contro!
@ Bandwidth {Q) control
© Variable equalizer switch: Lch. { EE off, = on)
@ Bandwidth (Q) contral
Band jevel controls : L ch, +12d8
@ Frequency control {Hz)
Band level controls : R ch. +12dB
@ Frequency control (Hz)
@ Variable equalizer switch : Rich. ( M off, = on)
input selector
input signal level saleetec
@ VARIABLE EQUALIZER
os “Technica: Information” on page 17 also describes me)
variable equalizer.
The variable 2qualizer can be used for corrections of
low-frequenc. characteristics. The functions in this unit
are as follows:
@ Center frequency contro! knob (frequency, Hz) is
able to cantinuously vary the frequency in a range
Of 20Hz ~ 400Hz to set it to the desired point.
@ Band width knob fhandwidth. O) ie able to conti-
hudusly .aty the resonance peak {Q) of frequency
set by knob 6 @_ in a range of 0.7~7. Turning it
counters 7ckwise decreases the value of Q, making
H
9a te ri a a an an Ahn Sie ma To © iets A hab fs dee rh MN wate on
LINE IN ! ——PLAYBACK =
: ae Dba eh I To Tape deck 2
Pa REC OUT el cae sn 4
PLAYBACK—————y
=
-
Low level ~ 150m V side {Input from “REC OUT" of amplifier: Output to “"PLAYBACK"’)
High level > 1V side (Input from “PRE OUT" of amplifier : Output to“MAIN IN’)
Voltage setector (110V/120V/220V/240V)
= To Tape deck 1
the peak and dip gentle, while turning it clockwise
increases the value of Q, making the peak and dip
sharp, resulting in less interference given by or to
adjacent channels.
©) Variable equatizer band level control is able to vary
the frequency set by knob @ by +12 dB.
If the frequency set by knob @ is 63 Hz, then it
can be varied +24 dB by using the knob @ and
the 22-division GB Hz band terel conirel Kage.
4) Variable equalizer switch (variable £Q) is a switch
to turn on/off the control knobs @ ~ @.
(16H2~25kHz, divided into 33 band in 1/3 octave.)
(16Hz~25kHz, divided into 33 band in 1/3 octave.)
ook
Sa
S29
@® OTHER SWITCHES
* Equalizer on/off switch (EQ)
This switch is used to turn on/off the equalizer circuit.
With it set to “on”, the frequency characteristic can be
varied by the upper and lower band level controls (33
sets each) and the variable equalizer band level controls
(1 set gach)... hy Bas
* With Jit: ‘set, to, "off “a signal is. ‘obtained not to make
%
“off, the signal comes out through the unit.
* Record mode switch (rec mode)
When recording on a tape deck, correction mode is
selected by this switch.
“EQ” is the position for recording with correction given,
@ DISASSEMBLY INSTRUCTIONS
@ How to remove the bottom board
. Remove the 8 setscrews {red) as in [Fig. 1] to reomve
the bottom board.
*Remove the bottom board from andenesih the
front pane! as shown by the arrows.
a Red ‘< (8 pes)
pte
oi Input selectar switch : 1 ie,
“Source” is the position “for record say: and radio
‘broadcast.
% 2 > #
, “equalizer cotrection.4 flan a7
* Even when power switch is off with this switch turned yee
lf the equalizer on/off switch is set to “off’’, the
“straight” indicator lights up and signal without correc-
tion will be recorded.
“Straight” is the position for recording without correc-
tion sae
“tape 1” is the position for playback on a tape deck
connected to “TAPE 1° terminal on the rear chassis or
for dubbing from tape deck 1 to 2.
“tape 2” is the position for playback on tape deck 2
or for dubbing from tape deck 2 to 1.
How to remove the front panel
1. Remove the setscrews @ ~ @ [Fig. 2] to remove
the cabinet.
2. Remove the 5 setscrews [Fig. 2] of the front panel.
3. Pull out the 6-pin connector {terminals @ ~ @]
from the switch P.C.B. on the left side. [Fig. 3]
4. Remove the front panel with care not to scratch the
knobs.
Power switch and
bottom connecting rod
Pull out the connector before
removing the front panel.
Front panet
~— Panel setscrews (5 pes)
Fig. 2

® How to remove the band level controj P.C.B.
if
2:
3;
Remove the front panel.
Remove the band level contro! knob. (The light guide
plate is removed with it.)
Remove the light shielding cloth. [Fig. 4]
_ Remove the 9 setscrews which secure the R or L
channel P.C.B. [Fig. 5}
. Remove the band level control P.C.B.
*Each control LED is inserted into the volume lever
with longer pin side down.
Setscrews af
switch P.C.B.
(4 pes.)
P.C.B. of teft ch. band
level contro!s
Light
guide plate
Knob
\
epe
Light
guide plate
Knob
2
insert with long
leg down,
Ss
Setscrews of rith ch. band fevei control P.C.B. {9 pes.)
Fig. 5
@ How to remove the switch P.C.B. and variable
equalizer P.C.B.
1. Remove the front panel.
2. Remove the 4 setscrews of switch P.C.B. [Fig. 5].
3. Pull out the switch P.C.B. fixing pin [Fig. 8].
4. Remove the 6-pin [terminals (43) ~ (48) ] and
7-pin [terminals (37) ~ (42) ] connectors from the
variable equalizer P.C.B. and then remove the switch
P.C.B. as in Fig. 6.
5. Check the P.C.B. as shown in Fig. 7.
Variable equalizer P.C.B.
Switch P.C.B.
connector
6-pin ;
~
as
jy
7-pin
connector
SS ACH
L
ua TRRD Woy
ass
ay
Power supply circuit
After repair, keep the
lead wire away from the
power supply circuit.
Fig. 8
s F
After repair a Button of power Push switch buttons Level control knobs
1.
Make
the
wiring
away
from
the
power
supply
switch
knob
bight
guide
circuit
as
in
Fig.
8.
plat
2.
Be
sure
to
fit
each
button
and
switch
in
correct
positions.
[Fig.
9]
.
3
.
Side
down
Side
down
Gate
hole
side
of
malding
;
should
be
down.
Fig. 9
m@ MODEL NO. SH-8065 BE DIFFERENT MODEL NO. SH-8075
Center
frequency
33
elements
(16
Hz
~
25
kHz,
1/3
octave}
Right
and
(No,
of
BPF
elements}
left, independent of each other.
Recording selector | “EQ position’ switch
“rec mode” switch
source
tape 1 (dubbing from tape 1 to 2}
tape 2 (dubbing fron tape 2 to 1)
source
tape {Playback}
Input selector
ot
Positive/negative characteristic Characteristic can be selected Not poss: bie
selection
with
the
switch.
(Selecting
switch
is
not
provided.}
Variable range selector +12 dB/+3 dB can be selected Not possible (+12 dB only)
(*) Variable equalizer selector Possible
{*} Band width control (Q)
Possible
: (0.7 ~ 7 continuously variable)
(*)
Center
frequency
control
of.
©
Possible
“] band level control
(*)
SH-8075
is
provided
with
variable
equalizer
circuit
so
that
the
center
frequency
(20
Hz
~
400
Hz)
end
its
band
width
other
than
the
other
band
levels
can
be
varied
by
variable
EQ
switch.
‘None
(6)

SH-8075 SH-8075
™@ PRINTED CIRCUIT BOARDS WIRING CONNECTION DIAGRAM
Orange
AC 110/420/220/240V
[sigwat Lever _](se) a >
LOW LEVEL == HIGH LEVEL ~~ -
: = TAPE 2-7 p TAPE i 4 “~ AMP
i ue os PLAYBACK = RECOUT PLAYBACK RECOUT LINEOUT LINEIN,
: oe +s
f
(58-1) { aan ee ’ a eee A 08 018 ~-IS aes = .
VOLTAGE
749
ta
ia
i
eto
fe
. i . J of J
($8+4)
SELECTOR
P.C.B.
(Top
view)
R
wR}
ifw
al
iiwr”
1
lw
i '
P p 2
a 69 —s«g 8 67 . ale ons ak itty
; ($1001) 0) Input/Output terminal, power supply lt ra thy aa
ane
Yellow
and
band
pass
filters
ao (T1001) Red]
Power transformer
(Bottom view
Se ae
|
|
|
Band level control of
variable equalizer
S~o
o~%
| P.C.B. (Top view)
. Input/Output controls
t — :
’ 25 P.C.B. (Top view)
zs 7 7 Variable equalizer
é
level controls (R ch.)
che
P.C.8.
{Bottom view)
VARIABLE
Indicators EQ (Q) (Me) EQ «1 @) (He)
I Lery ——! — Rignt ——

SH-8075
H PRINTED CIRCUIT BOARDS
[ej P.C.B. (INDICATORS)
To fe PCB.
ToB}PC.B.
| (- B) ae
To ‘(LINE OUT) termina eiay Fro
From Pj PC.B. Muting sw a a B
From (LINE IN) terminal
—(‘uobing 1»
S
|
ae
¥
dubbing 2>
— 2 PLAYBACK) (CUMIN Bo SN es ; =
To (tane? RFC un) terminal - me" : Font — PLAYBACK)
Tp (tepef REC OUT) A
To inverter of BPF.
| SiG NAL LEVEL |

SH-8075 SH-8075
P.C.B. (BAND LEVEL CONTROLS, LEFT CH.)
J102
I
{
ake
‘ J
Or! gel.
a - .
J104
f
x
~~
at.
oh:
“yeh
AL
O°
3106
oj
Dp BOB. (BAND LEVEL CONTROLS. RIGHT cH,)

Fil .c.8. (POWER SUPPLY AND BAND PASS FILTERS)
TAPE 2
AMP—~ TAPE j ,
[LINE
IN
|[LINE
OUT
|[REC
OUT}[PLAYBACK]
[REC
OUT][PLAYBACK]
From
EY
PCB,
ACK
eo

SH-8075 SH-8075
[a Pcs.
( BAND LEVEL CONTROL
\. OF VARIABLE EQUALIZER
Ee! P.C.B. (VARIABLE EQUALIZER) “ S :
LEFT
bes
Leon] | [VARIABLE Ea
i
S&
5n
——~
Off
Gutput circuit \7p-
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3 «
3
||
[BAND
siDTH(@)
+8
-B
To EY 2C.8 Muting
| | [FREQUENCY (Hz)
eae Relay
Power
supply
circuit
|
Muting
From EY PCB.
+B-
RIGHT
}j action] ] [vaRiaBce Ea
S7 on ——~ Off
|] [Bano widTH (a)
| | TEREQUENCY (H
Me ile vee ae ee
me
*
Pe
ie
20~400HzZ BAND LEVEL

SH-8075
@ TECHNICAL INFORMATION
@ Variable equalizer circuit
(for varying the center frequency and band width) Integrator Integrator | Adder/Subtractor
The band pass filter of this unit is designed so that
the resonance peak characteristic (band width: Q)
is constant at 5. With the variable equalizer switch set
at “on”, the center frequency and resonance peak
characteristic, only for 20 Hz ~ 400 Hz, and the
frequency band level as well as the other band level
can be varied. -
Fig. 1 is a variable equalizer circuit consisting of 3
operation amplifiers (1 adder/subtractor and 2
integrators). The center frequency (fo) of band pass
* Band ievel is
at +12 dB.
filter is determined by the time constant of R and C, : e pay ee A
and the frequency is varied by double-acting volume poodle! preauency (fo) Bandwidth (Q) varies by r.
R. The resonance peak characteristic is varied by :
double-acting volume r. . Fig. 1
© Band level control circuit |
(for varying the center frequen): by #12 dB)
abe Loe eae ss * ¥
Fig. 2 is a circuit that ‘ibs the frequency charac: eee
teristic of peak anddip. a
When the band level control volume. is at middle
position @, BPF is off the circuit, therefore the
input/output gain (G) is as follows:
As VR is shifted t to 0 ®. i input Gon R3 and output of (ore cer
BPF are added as the output to give the following: . or a Shifted from @—-@
R.,
_
(Peak
characteristic)
(=7+4 aT)
G=
Band leval control.
Tg
:
gain
characteristic
of
BPF
As
VR
is
shifted
to
©,
synthesized
NFB
of
BPF
and
Fig.
2
R2
is
given,
thereby
making
a
frequency
characteris-
tic
having
a
dip.
Response of bandwidth contro! (Q) Definition
ne
| | | INN |
oN
ZING
“NA
. “nq expresses the sharpness of
~ the peak and the dip, and its
value is expressed as the value
Steere! a ary obtained” “when” the’ “center 9 aOR Se sete:
frequency (fo) is decreased by
3
06
less
than
the
peak
point
(the dip point is increased by 3
dB), and is divided by the
frequency range(Af = f, — f,).
fo
: Af