Sankyo STD-1700 Troubleshooting guide

Sankyo
STEREO
CASSETTE
DECK
mone feud, 1800
=¥ eB, 1700
Service Manual-Parts List
; : ra) QO sonkye :
STD-1800
STD-1700
Sankyo
Seiki
Mfg.
Co.,
Ltd.
17-2,
1-Chome,
Shinbashi,
Minato-ku,
Tokyo
105,
Japan
Sankyo
Seiki
(America)
Inc. 149
Fifth
Avenue,
New
York,
N.Y.
10010,
U.S.A.
991
Francisco
Street
Torrance,
California
90502,
U.S.A.
Sankyo
(Europe)
Export
und
Import
G.m.b.H.
Viersener
Strae
58,
4
Diisseldorf
11,
West
Gernany
Sankyo
Seiki
(Hong
Kong)
Co.,
Ltd.
Room
1301,
Metropole
Bidg.,
No.
57
Peking
Road,
|
Kowloon,
Hong
Kong

CONTENTS
1.
10.
11.
Specitications:,. 0c desicic sre see Shek eaten a vena eS ork CUA Ne aa GS Ea wah ete n Wabaee a ule w Soo ah ace ae ea 1
Parts identification
2.1. Control Panels eceecide ook wie he eras s ele Ee eae: Sa Whe PE Seah ose Ak baad Oat ae he Ae 2
2:2” {Connection Panel .z-cis ieee sdhecs yah eS ya eras Oe Tete cde de Seo Be Rite dranete ie aed Sh bistdlene ne bleh ee ee eS 2
2:3.-. side tOD. ViOW ci .5: oo eee ered ioe Seo ete Saco le aed eal ae Ba ere ee ped OE See Bee OY 3
2.4. “Inside DOttOm VieW: & acces ecar egies eae dG. oe Ge we al eae ee Ue uae lok wee WARS Laos 3
Technical description
3:1. Power supply Circuit: s.2.85 vee dew ee ceca ane es Weg aes case ER Wie BAL oa EE ee, Oe aw “e.3 wea 4
3:2. - Amplifier SeCtion.. sc-5 ice S sacs the Sos casa te eae Gor be oe eileen oa’ ScBuae Oo, S yay ot Sed ela eA, Beato lohan Shey ae eee 4
3.3 Cassette loading and unloading ........ 0... 0c ce eee ee ee ee eee eee ee tee ent e eee nee 4
Disassembly
4:1. ‘Removal:-of the: bonnet: <- o ves"s Gee ed eas iw Geese teed oe’ db Gwe BG REO en ere evened aan GiAla 5
4.2 Removal of the bottom plate 2... 2. . eee ee ee eee ee tence eee 5
4.3 Removal of the front panel... 0... ee ee ee ee eee eee ee tee ee teens 5
4.4 Removal of the cassette compartment .. 10... 0... cc ee eee ee ee ee et eee eee eens 5
4.5 Removal of the tape transport mechanism chassis ... 2... eee ee ee eee ee ee eee ee eee 5
Mechanical adjustment
Bt Forward: timing: .cce ik oe ee hited SHaee ek @ Siage nd rea Beg Shona eave dees & aoe Sob adh Leta 6
5.2 . Pause: timing «<i. Sean wate GES GOS ew meee Bee Wale ed Seer Save: wie vera car ge di nce ebbad awed blac wae 6
BiB sReel torQue:c, ites Seen geaee nee doe Mice allan’ settacsatie ey obs SS NSS a alcoho 1S Waptaliean%e, we Biles PUdeS aM Oe takes SA Re 7
5.4 Shut-off mechanism ...........-...00-. ea teeta age Bie han Soe le dhe at Banh tein ok te nok, 8
5:5. <Pineh-froller: pressure: inde c tie) does oocea eee actos 6a, oo base 6 bye are ce Bava tans ww de bnea ee $0 Sn boat aay 9
BiG: (Motor: DUlley cence ie Sites. dee wreck Ge ew Rie ei se Bite Bie woae By ne cw ovate a doe ele Geen A ees beee 10
Bi7> - Flywheel: thrust: 6: 0.0360, 5 eccee bie ded ed oe be TA ab ere eae ek Gnas Sinhala a a alae 10
5.8 Mutingswitch timing. ...... 0... cee eee ee eee ee eee eee eee ene ee eee nena 10
5.9 Wow and flutter and tape speed. 2... ke ce ee eee ee ene eee eee eens 11
BVO) CGA ING? 530 seo seat ke ee DF ate eee ate w Cac he Sete e es Rade a ata Eadie oh 2 Gils smb eee. MULE A eve aS 11
Electrical adjustment
6.1 Playback system block and level diagrams ......... 0.0 cece eee eee eee eee eee eens 12
6.2 Recording system block and level diagrams .. 0.1... 00. cee ee ee ee ee eee eee ee eee eens 12
6.3 DC voltage block diagram... 6 ee eee eee eee 13
Ge4e MIP XSTINGR ee is ere Scat at dele facies ce enti ee'g 0/70, We Se ab-atrereees @ face ded’ gain Sus hhc nane hive ost paca toto rsteuname Saweadsalers 13
6.5 Bias oscillator frequency ...... ccc ee ee eee eee ee eee ee et eee nena 13
6.6; ead saZimuthy icece oar She sciats Ga ae aa ww ad BOE wk eS ale BYG Rie hglew ces Ges © wire lanchy a) alana “nel Votes ee 13
6.7. Playback level and VU meters 1.0... ec ee eee ee ee eee eens 14
6.8. Playback equalizer: cs:c:ocja: esece. i Soo ek a faced egel had Ste ae ble aces Setwnde tae wae SCARY Cb ba 14
6:9. Recording Current: js. S553 5 cose ee GS, aera Gate ce Gokeegadsale: dyeehs: arterend Wi Golere 4: @hevaph Wl epee ptauetel eteva-d uae 14
6.1.0" Bias CUPEMES secure hrettacaaeere SOR ale seers ed artes te Behe, 5 hentia haat: weedeat ee avid dete ane wigeaaatoeyetes 14
E:ubrication o'. cen: c.ccecen te Bie ale: fot ech a Geter bay Tals ioe ows ateal a fo as Bes eo eele ton See ee teiea lovelies 15
Troubleshooting
8.1 - Mechanical parts: ssc.cs scacei a bereits ee Rane dk ce ES eae aw ee nee ee eee bale b eUble'a @oe elwacd etel aes 16
Be2- ClSCLrical: Parts ise: esr: seen Sain ciate a Wwe aces OS ts ane Sac bE wh SMa wwe ae Renew bat bid abieet lag colle ele 17
Drawings and electrical parts list
9.1 Schematic diagrams (STD-1800/1700) «6.2... eee ee eee ene 18
9:2° Electrical: parts: VSt® iyi we < sustie desea nassasas his i Allee a nde wee oe teheeinae ts ay, Sera iee w vatsloshk Gadde whieh aive, &e Morse ds Bo awed 21
9.3. Mounting and wiring diagrams (STD-1800/1700) ..... 0.0.0.0... cee cece eee eee eens 23
9.4 Dolby P.C.B. mounting and wiring diagram ... 0.0... ee ee ee ee eee eee nee 25
Exploded ‘Views: s 026. <0 .6c ake wheita anda ew ef eee ens Pee Sasa eee vad Woe DNS a Soy Ast ae has ata ah aMtataatta Sts Gt igs 26
Mechanical: parts: list): seis: ond kos aire doe eile atanel acca tated os Seacaid lenge a eee Sc Sa oe 8 dew GhevOaneechad aad 29

Type
Power requirement
Power consumption
Dimensions
Weight
Cassette
Tape speed
Fast forward time
Rewind time
Recording time
Recording system
Erasing system
Terminals
Wow and flutter
Signal-to-noise ratio
Frequency response
Distortion
Subfunctions
Semiconductors
Standard accessories
Operation manual
Warranty card
1.SPECIFICATIONS
STD-1800
Philips cassette tape 2-channel stereo
USA, CND AC 120 V, 60 Hz
AEP AC 220 V, 50 Hz
ENG AC 240 V, 50 Hz
MVD AC 110 — 120/220 —
240 V, 50/60 Hz
AC 15 W
400(W) x 150(H) x 250(D) mm
6.2 kg
C-30, C-60, C-90, C-120
4.76 cm/sec
Less than 90 sec (with C-60)
Less than 90 sec (with C-60)
120 min. (with C-120)
AC bias, 80 kHz
AC erasing
LINE IN 50 mV (50 kQ)
L—MIC—R/PB/REC (DIN)
0.5 mV (5 kQ)
LINE OUT 1.25 V ) with
PHONES 2 mW Dolby
(8 Q or 600 Q) tape
PB/REC (DIN) 580 mV) MTT-150
Less than 0.095 % WRMS
52 dB (Normal) Dolby
55 dB (CrO2) OFF
60 dB (Normal) Dolby
63 dB (CrO2) ON
40 — 12 500 Hz (Normal)
40 — 15 000 Hz (CrO2)
2.0 % (Normal)
2.5 % (CrO2)
Tape select switches
BIAS (NORM/FeCr/CrO2)
EQ (NORM/FeCr/CrO2)
Dolby NR switch
DOLBY NR (OFF/ON)
Limiter switch
LIMITER (OFF/ON)
Green LED Dolby NR indicator
Red LED recording indicator
3-Digit tape counter
Transistors 18
ICs 2
Diodes 19
LEDs 2
Head cleaning kit 1
Stereo connecting cord
(USA, CND, MVD)
DIN type connecting cord
(AEP, ENG)
1
1
STD-1700
Philips cassette 2-channel stereo
USA, CND AC 120 V, 60 Hz
AEP AC 220 V, 50 Hz
ENG AC 240V, 50 Hz
MVD AC 110 — 120/220 —
240 V, 50/60 Hz
AC 15 W
360(W) x 150(H) x 250(D) mm
6.2 kg
C-30, C-60, C-90, C-120
4.76 cm/sec
Less than 90 sec (with C-60)
Less than 90 sec (with C-60)
120 min. (with C-120)
AC bias, 80 kHz
AC erasing
LINE IN 50 mV (50 kQ)
L—MIC—R/PB/REC (DIN)
0.5 mV (5 kQ2)
LINE OUT 900 mV with
PHONES 1 mW Dolby
(8 Q or 600 2) tape
PB/REC (DIN) 580 mV} MTT-150
Less than 0.22 % WRMS
52 dB (Normal) Dolby
55 dB (CrO2) OFF
60 dB (Normal) Dolby
63 dB (CrO2) ON
40 — 12 000 Hz (Normal)
40 — 15 000 (CrO2)
2.0 % (Normal)
2.5 % (CrO2)
Tape select switch
TAPE (NORM/CrO2)
Dolby NR
DOLBY NR (OFF/ON)
Red LED recording indicator
3-Digit tape counter
Transistors 14
ICs 2
Diodes 17
LED 1
Head cleaning kit 1
Stereo connecting cords
(USA, CND, MVD)
DIN type connecting cord
(AEP, ENG)
1
1
Note: For improvement, design and specifications subject to change without notice.
Note:
This service manual has been prepared for two models — the STD-1800 and STD-1700. Servicing is almost identical for
both models. Some differences are clearly described followed by their model numbers. Please check the necissary infor-
mation relevant to the model you are servicing.

2.PARTS IDENTIFICATION
2.1 Control panel
Headphone jack
Power switch
Record lever
Rewind lever
Play lever
Fast forward lever
Stop lever
Pause Jever
Microphone jacks
10. Dolby” noise reduction switch
11. Tape bias select switch (STD-1800 only)
12. Tape equalization select switch (STD-1800 only)
13. Tape select switch (STD-1700 only)
14. Limiter switch (STD-1800 only)
15. Output level control (STD-1800 only)
16. Recording level control
17. VU meters
18. Counter reset button
@ 8 ® 19. Tape counter
20. Recording indicator
21. Dolby noise reduction indicator (STD-1800 only)
22. Cassette door
23. LINE OUT jacks
Note: A voltage selector is provided on the MVD version. 24. DIN jack
* Dolby is a trademark of Dolby Laboratories Inc. 25. LINE IN jacks.
2.2. Connection panel
00 SS Ol Be NS

2.3 Inside top view
STD-1800
Dolby P.C.8,
R210
Jo. B. equalizer)
202, C203
(P. 8. equalizer)
102, C103
F227 (UV meter) Fuse P.C.8.
Power transformer
R143 (Recording currant)
Ls02
Oscillator brock (Bias osciltator frequency)
A146 (Bias current)
R246 (Bias current)
R127 (UV meter) A243 (Recording current)
2.4 Inside bottom view
STD-1800
Recording jevel control volume (R111, 211)
ze Output level contro! volume (R139, 239):
Microphone jacks
Power switch
Wis By
Mather P.C.B.
STD-1700
Dolby P.C.B.
A210
A205
R106
lo. B. equalizer)
€202, 203
(P, B. equalizer)
C102, 103
A110 Motor
R227
{UV meter)
Power transformer
tso2 A143 (Recording current)
Oscillator brock (Bias oscillator frequency)
Rig6|
(Bias current)
R246
R427 (UV meter): R243 (Recording currant)
STD-1700
Recording level contro! volume IR2 11)
Recording tavel control volume (A171)
Microphone
Power switch
Mothup .C.8.
cima i a a a

3.TECHNICAL DESCRIPTION
3.1 Power supply circuit
A voltage regulator circuit is provided to supply
constant voltage to the bias oscillator in the
amplifier block so that the bias oscillator is not
affected by voltage supply fluctuations. Power
supply to the motor is independent of the voltage
regulator circuit.
3.2 Amplifier section
The Dolby NR circuit employs IC element and
does not require adjustment. The emitter-follower
used in the headphone amplifier circuit ensures
sufficient volume even if the headphone impe-
dance is high. During recording and playback
the OUTPUT LEVEL control functions for only
the outputs from the LINE OUT and headphone
jacks and has no effect on the meter. During
recording, no output appears at the DIN output
terminal, but during playback an output inde-
pendent of the OUTPUT LEVEL control is
provided.
3.3 Cassette loading and unloading
Loading aca a a aac
1. Open the cassette door by gently lifting the
door tab.
2. Hold the cassette vertical with the side you
wish to play or record facing toward you and
the edge of exposed tape pointing downward. 3 7 :
3. Install the cassette by pressing lightly upward = case qunamnamenr teas eet
until it snaps in. Sankyo ;
4, Close the door.
Note:
To prevent dust from entering the mechanism,
always keep the door closed.
Unloading
1. Remove the cassette with a slight upward and
outward movement.

4.DISASSEMBLY
4.1 Removal of the bonnet
Remove four screws (1) on either side and pull the
bonnet (2) backward with a slight outward
pressure onto both side panels.
4.2 Removal of the bottom plate
Remove ten screws (3).
First pull away the VOLUME and LEVEL control
knobs. Remove four screws (4). Then pull the
front panel forward.
4.3. Removal of the front panel |
4.4 Removal of the cassette compartment
Remove three screws (5).

5.MECHANICAL ADJUSTMENT
5.1 Forward timing
1. Slowly depress the forward button. When the Subply:reel base
reel base contacts the tension pulley and
begins to turn, the space between the capstan
and pinch roller should be within 1mm.
However, the pinch roller should not start
turning before the reel base.
Take-up reel base
Capstan Less than 1 mm
Pinch roller-—t
Adjust the timing by bending this
plate with pliers, etc.
5.2 Pause timing
Load the tape and adjust the timing. Take-up reel base Reet driver roller
1. Bend the pinch roller arm in the direction
of either a or b so that the reel base and pinch ,
simultaneously when the pause switch is slowly euremerns
depressed. ,
Note: Load the tape, slowly depress the pause
switch and confirm that there is no tape
friction noise when the tape begins to run.
Pinch roller arm
Pause lever

5.3 Reel torque
Forward torque
1.
2.
4.
Clean the tension pulley and reel base wheel.
Read the reel torque on the cassette torque
meter and make sure the torque is within 40 —
70 g.cm.
. If the torque is not correct, turn the plate
shown in the figure with a screwdriver or
tweezers until it is positioned at the center
of the most suitable of the three cam surfaces.
If the torque is still incorrect, replace the
tension pulley assembly.
Fast forward, rewind torque
1.
2.
Clean the idler pulleys and reel base wheels.
Read the reel torque on the cassette torque
meter and make sure-the torque is within 70 —
150 g.cm.
. If the torque is not correct, replace the idler
assembly.
Turning the plate adjusts the forward torque
to three different degrees.
Three cam faces

5.4 Shut-off mechanism
(1) Adjusting the fink allowance
1. Turn and position the shut-off pulley so that
the gear wheel pin (C) moves the shut-off lever
to its farthest position in the direction of the
arrow (a). (Fig. A)
2. Loosen the screws and move the clamp arm
until the link allowance in the direction of the
arrow $ (d) is 0.1 — 0.3 mm, with the link held
positioned in the direction of the arrow + (b)
by the link allowance. (Fig. A)
Note: After adjusting the link allowance, apply
screw lock paint to the clamp arm ad-
justing screws.
Shut-off
pulley
The farthest <_—_
position of
the fever
Move by the link <<—
allowance b
Adjusting screw
Shut-off pulley

(2)
(3)
5.5
Adjusting the detect pin position
1.
Turn
and
position
the
shut-off
pulley
so
that
the
shut-off
lever
does
not
make
contact
with
the
gear
wheel
pin.
(Fig.
B)
.
Adjust
the
detect
cam
and
pin
to
the
po-
sitions
shown
in
Fig.
C
by
bending
the
detect
lever,
(The
detect
pin
should
be
within
the
@
part.)
_
Turn
the
detect
cam
in
the
direction
of
the
arrow
4
(Fig.
D)
and
confirm
that
the
detect
pin
returns
to
the
former
position
smoothly
(without
making
any
contact
at
C);
from
A
to
B
and
vice-versa.
(Fig.
D)
.
Changing
from
the
forward
mode
to
the
stop
mode
should
not
change
the
detect
pin
po-
sition.
Adjusting
the
detect
cam
clearance
(in
the
rewind
mode)
He
In
the
rewind
mode,
move
the
detect
cam
so
that
the
detect
pin
takes
the
position
as
shown
Fig.
E.
.
Adjust
the
clearance
between
the
brake
plate
and detect cam to 1 — 2mm.
Note:
The
detect
cam
must
be
engaged
with
the
upper side of the brake.
Pinch roller pressure
Specified
pinch
roller
pressure:
300
—
400
g
1.
If
pinch
roller
pressure
is
insufficient,
adjust
by
bending
the
pinch
roller
spring
toward
a.
2.
If
the
pinch
roller
pressure
is
excessive,
adjust
by
bending
the
pinch
roller
spring
toward
b.
Note:
When
bending
the
pinch
roller
spring
exer-
cise
care
to
prevent
damage
to
the
surface
of
the
pinch
roller
arm.
Detect lever
_Detect cam
Take-up reel base
Detect cam
Brake plate
Take-up reel base
Detect cam
Capstan shaft Pinch roller
Pinch roller shaft
Pinch roller spring

10
5.6
5.7
5.8
Motor pulley
Position the motor pulley so that the clearance
between the motor and motor pulley is 2 mm, as
shown. Then, tighten the screw securely. Apply
screw lock paint to the screw head after tightening
the screw.
Flywheel thrust
1. Adjust the thrust clearance to 0.1 — 0.3 mm by
turning the thrust adjusting screw.
2. Turn the screw clockwise to decrease the al-
lowance, and counterclockwise to increase it.
3. After the adjustment, apply screw lock paint to
the screw head.
Muting switch timing
When the play lever is slowly depressed, the
muting switch should be switched over, just before
or at the same time as the play lever is locked. (Do
not depress the play lever with an excessive force.)
The upper and lower units of the muting switch
should function simultaneously (although a slight
time lag is permissible). To adjust to the correct
timing, bend the head lever in the direction of the
arrow,
STD-1800
Head lever
Adjust by turning this screw

5.9
5.10
Wow and flutter and tape speed
LINE OUT Frequency
Wow and flutter check TEAC MTT.111 counter
1. Play back the test tape (TEAC MTT.111).
Read the wow and flutter meter. (within . Test tape
0.095% (WRMS) (STD-1800) x =0.040%
within 0.22% (WRMS) (STD-1700) x=
0.12 % (see the figure)
Tape speed
1. Turn the power switch ON. Allow the motor to
idle for 20 seconds.
Using a screwdriver inserted in the adjustment
hole, adjust until the frequency is between
3 000 Hz and + 45 Hz (STD-1800).
STD-1700
In the case of the STD-1700, confirm that the
frequency is between 3000 Hz and + 60 Hz.
If the frequency is not such, replace the motor.
Cleaning
Clean the heads, capstan and pinch roller with a
cotton swab (Q tip). When excessively dirty,
soak the swab in some alcohol,
POWER
Playback ampl. section
Wow & Flutter
meter
Speed tape
adjustment hole
asTor
PAUSE mt

6.ELECTRICAL ADJUSTMENT
6.1. Playback system block and level diagrams
Line Amp.
Dolby Amp. ®
104
HEADPHONE
R110, 210 R139, 239
nd Oo i rt
De cane utput volume ISTD-1800}
Dolby Amp.
7) LINE OUT
(REC/PB) ?
& Meter Amp,
10
5 6 7 10 11 42 13 and 14 are identical with those of recording level diagram.
+30 d8s
+20 Bs
+5.5 dBs (ST0-1800)
HEAOPHONE (600 2)
& LINE OUT (OPEN)
0.775 V = OdBs
HEADPHONE (600 22)
LINE OUT (OPEN) {STD-1700)
-14.5 dBs
‘ © HEADPHONE (8 2) (STD-1800)
\L-——_ HEADPHONE (8 12) {STD-1700)
“17.5 dBs
6.2 Recording system block and level diagrams
prc
Une IN
© crrwur vowme, Line Amp
aoa
R139,228 ®@ ©@ ®
HEADPHONE
Ree. Volume
nnn, 219
OWN LINE OUT
IREC/PB}
Rec. EO. Amp.
& Meter Amp.
R143, 249
430 aBs
4200Be
+5.5.dBs +55 dbs (8TO-1800)
HEADPHONE (600 12)
& LINE OUT (OPEN)
0.778 V= OdBr
(sTD-1700) .
HEADPHONE 1600 2)
& LINE OUT (OPEN)
HEADPHONE (8 2)
Teuer (STD-1800)
HEADPHONE (8 9)
isTD-1700)
~60 486 (C102)
-62.5 GBs (Norm)

6.3 DC voltage block diagram
DC VOLTAGE DIAGRAM (Unit: Volt)
17.3V @ @
(41.7 V)
iJ
Power trans.
6.4 MPX filter
Apply a signal of 400 Hz-20 dB to the LINE IN terminals and adjust the RECORD LEVEL control until an output
of -2:5 dB is obtained from the LINE OUT terminals (with the OUTPUT LEVEL control at maximum). Then apply
a signal of 19 kHz -20 dB to the LINE IN terminals and adjust L502 for minimum output.
600 2 600 2 LINE IN LINE OUT
6 =
6.5 Bias oscillator frequency
Connect a frequency counter to the terminals of the erase head and adjust the oscillator block to an oscillating
frequency of 80 kHz + 5 kHz.
Erase Head Counter
6.6 Head azimuth
Play back the test tape (MTT-114) and adjust for maximum output.
OSCILOSCOPE
Adjsuting Nut
2 Side 1
DECK
under Test
Head Phase Check Setup
|
Head Azimuth Adjustments Location
13

14
6.7
6.8
6.9
6.10
Playback level and VU meters
Playback the test tape (MTT-150) and adjust R110 (left channel) and R210 (right channel until an output of
—2.5 dB is obtained from pins 3 and 5 of the DIN jack. Then adjust R127 (left channel) and R227 (right channel)
until the meter indicator diflects to +3 VU.
Playback equalizer
Set the EQ switch to CrO2, play the test tape (MTT-116K) and adjust R105 (left channel) and R205 (right channel)
until the frequency response from the LINE OUT terminals is of the same level at 500 Hz and 2 kHz. Then adjust
the parts marked with A in the mounting diagram C102, C103 (left channel), C202, C203 (right channel) until the
frequency response from the LINE OUT terminals is of the same level at 2 kHz and 10 kHz (see Note No. 3 of
the mounting diagram).
40 125 315 6.3K 10K
Recording current
Load the MTT-502 tape. Set the EQ and bias switches to NORM and apply an input of -20 dB, 400 Hz to the
LINE tN terminals. In the record mode adjust the RECORD LEVEL control until the meter indicator deflects to
+3 VU. Play the tape back and adjust R143 (left channel) and R243 (right channel) until the output is +3 VU (at
this time the semi-fixed resistor for bias current adjustment should be at the mechanical mid-position.)
600 Q 600 2 LINE IN
e =
Bias current
Load
the
MTT-502
tape.
Set
the
EQ
and
bias
switches
to
NORM
and
the
DOLBY
NR
switch
to
ON.
Apply
an
input
of
-20
dB
to
the
LINE
IN
terminals
and
adjust
the
RECORD
LEVEL
contro!
until
the
meter
indicator
deflects
to
+3
VU
at
1
kHz.
Then,
apply
an
input
of
-50
dB
(1
kHz
or
10
kHz)
to
the
LINE
IN
terminals
and
record.
Play
the
tape back and
adjust
R146
(left
channel)
and R246
(right
channel)
until
the
playback
outputs
of
the
LINE OUT
terminals
of
1
kHz
and
10
kHz
are
of
the
same
level
(at
this
time,
the
OUTPUT
LEVEL
control
is
at
maximum).
600 2 600 22 LINE IN LINE OUT
CY) ATT DECK VTVM
40 125 400 Normal (Fe203) 6.3K 10K

7.LUBRICATION
Reel shaft Mitsubishi Apply oil to contact surface between
reel shaft and reel disc.
Flywheel-capstan | Mitsubishi (1) Apply oil to contact surface
shaft/Adjusting between capstan shaft (3) and
screw hollow SG101 metal bearing. 2
[fy
(2) Apply grease to end of capstan Y Y/;
shaft and hollow of thrust YN G
ae Grease
adjusting screw (82).
@ Adjusting screw
Supply reel disc Mitsubishi Apply oil to contact surface between
felt (90) and reel disc (77).
Take-up reel disc | Mitsubishi Apply oil to take-up reel disc where
detect cam (86) contacts,
Grease
Detect
cam
$G
101
Apply
grease
to
the
detect
pin
guide
slot
in
detect
cam
(86).
Mitsubishi
Apply
oil
to
detect
cam
where
compression
spring
(87)
contacts.
Shut-off Apply grease to the worm and
assembly gear surfaces.
Apply grease to both ends of
compression spring.
Apply grease in the slot through
which lever and link are linked.
if
|
Grease

- 8. TROUBLESHOOTING
8.1. Mechanical parts
16
Motor does not turn. 1. Switch defective. Replace.
2. Motor defective. Replace.
Tape does not run 1. Tension belt, motor pulley or pinch roller Clean.
slipping due to oil or dirt.
2. Tension belt disengaged. Engage.
3. Motor pulley screws loose. Tighten.
4. Pinch roller pressure insufficient. Adjust.
Tape winds onto 1. Defective pinch roller Clean or replace.
capstan shaft. 2. Defective take-up reel table a’ssy Replace.
3. Tape path wrong (improper tape guide Adjust.
position and bad head mounting).
Capstan does not rotate. 1. Capstan belt off Engage.
2. Defective motor Replace.
Index counter will not 1. Counter reset button not fully depressed. Replace.
count. 2. Counter belt off. Engage.
Shut-off T Shut-off does 1. Link allowance insufficient. Adjust stopper
failure not work or plate arm.
works Rearrange wires.
intermittently. Adjust leaf switch
clearance.
2. Coil spring badly positioned against detect cam. Adjust spring
position.
Shut-off works | 1. Top spring of detect cam making contact with Adjust clearance.
during FF or brake plate.
REW. 2. Detect cam not following the reel disc rotation. Clean and oil
detect cam.
3. Coil spring badly positioned against detect cam. Increase compres-
sion spring force.
Shut-off works | Detect cam spring incorrectly shaped. Adjust and reshape.
at PAUSE
Wow and flutter excessive. 1. Tape speed unstable due to oil or dirt on ap Clean.
pinch roller or capstan.
2. Oil or dirt on tension belt. Clean.
3. Pinch roller pressure insufficient. Adjust.
4. Motor defective. Replace.
5. Bad tape. Use good tapes.
6. Forward torque improper. Adjust.
7. Flat belt defective. Replace
Rewind
and/or
fast
forward
1.
Reel
disc
tire,
idler
and/or
flywheel
slipping
Clean.
impossible. due to oil or dirt.
2. Friction of idler lever assembly insufficient. Adjust.
3. Motor defective. Replace.

8.2
Electrical parts
1. No playback sound.
1-1.
Touching the head terminals produces-sound.
Head out of alignment.
Head terminals incorrectly soldered.
Recording sound can be heard (LINE IN input)
Q501, 502 defective.
R110/210 contact failure.
Sound heard from headphones, but no sound at
LINE OUT.
LINE OUT terminals defective.
Sound at LINE OUT terminals, but no sound
from headphones.
Headphones jack defective.
Headphones jack disconnected or lead wires
broken.
During
playback,
sound
at
pins
3
and
5
of
the
DIN
jack,
but
no
sound
from
LINE
OUT
terminals
and
headphones.
Q103/203, 0104/204 defective.
No sound.
S5-1/5-2 contact failure.
Lead wires to S5-1/5-2 broken or disconnected.
Dolby-NR_ IC (NE545B) defective.
Q103/203, 0104/204 defective.
Only noise is produced.
Open in the Dolby circuit board.
Lead wires of OUTPUT VOLUME broken
(only STD-1800). .
Lead wires of OUTPUT VOLUME defective
(only STD-1800).
2 Recording impossible.
2-1,
°
e
e
2-2.
2-3.
yg
P~eee
Erasure impossible.
Bias oscillator inoperative.
Erase head out of alignment.
Lead wires of erase head broken or disconnected.
Erasure possible.
Q101/201, Q102/202 defective.
R143/243 contact failure.
Lead wires to LINE IN terminals broken.
LINE IN terminals defective.
Lead wires to R111/211 broken.
Recording impossible from MIC jacks.
MIC jacks defective.
Lead wires to MIC jacks broken.
LINE IN terminals defective.
Recording impossible from DIN jack.
Lead wires to DIN jack broken.
DIN jack defective.
MIC jacks defective.
Lead wires to MIC jacks broken.
LINE IN terminals defective.
3. Playback sound weak.
3-1. Abnormal signal noise ratio.
@ Dirty head.
3-2. Both sound and signal are weak.
@ R110/210 improperly adjusted.
@ R139/239 defective, lead wires broken
(only STD-1800).
@ Q1 defective.
@ D7 defective.
4. Meter lamp does not light.
@ Lamp burnt out.
@ Lead wires to lamp broken or disconnected.
5. Recording indicator does not light.
@ D1 defective.
@ Lead wires to D1 broken or disconnected.
6. Dolby indicator does not light (only STD-1800).
@ D2 defective.
@ Lead wires to D2 broken or disconnected.
7. Abnormal signal noise ratio.
@ (Q1 defective.
8. No power.
@ Power switch defective.
@ Blown fuse.
@ Q1, D3-D6, D7 defective.
17
See RET ER eT ST ae Oe ET See ae eee eT eee Ane

9.DRAWINGS AND ELECTRICAL PARTS LIST
9.1 Schematic diagrams i Rae
STD-1800
=
20.3V 19 OV
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MuF/1b
+B2
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+B)
C$08033uF / 72 SS
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SI5B
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(EF).
&
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@{o 7ev
§
AIR
f+
Cys
MF
/50
&iaySk
=
Zz
a
=
$77
H
250945
(K)
8
3
8
;
Qi0a
he
/23V
4
C9 tll F Wb
xs a Cre TU t
ty R39. 7K
x H (O) iN our
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Rsy2!O
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SS
GND
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Y : ha)
20Bv, s
YOM) 250995 (K.P) G
JESVIC, Q, 8 O
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:
38
CO}
se
ec
PPT
(x)
Sxl
8
HP
4 t
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SSS
5 SS
£y2/0K a “J alts
O oO Na
AYER
|
Soe
WE
O00 OOO Oe
5 Ss MOO Se-y
Svob S107 ™
ie g
36mH Raal0k ' y
pp
743 20K
C25 /00P
/01V(NORM)
Ov (Croz)
a ae a eA a he ah Me ed 5
|
as
aa
a
hg
he
as
Di
eth
OS
Soe
a
rae
Beh
pa uc
eS
ny
Sele
he
Ses
sy
Re
22K
20.3V
(NORM)
Pe
eae,
eR
eee
eT
ON
I
19.7V (CrO2)
202v (warn) *20.3V (WORM) |
12V (Cros) Bee
SyomSi09(S0)%S20a) REC/PB Switch NOTES: 1. Syopn 8109 (Sooi Saga)
Sa
Hav
RID
HEA
BED
ne
ee
Sis
Dolby
we
Switch
(PLAY
BACK
POSITION)
2-1,S2-2 Bras Switch 2. LACK NO. B49, R247
tB2 203V(PRE. DOLBY. REC. AMP Leh. :
:
x
{
ch)
ne
en
Se
4
S3
EQ
Switch
R101
®
201»
R375
R237
8
s
+B3
203V
(PRE.
DOLBY.
REC.
AMP
Rch)
(FOR
CNDY
Sar
,(S4-2)
Limiter
Switch
Cros.
©205,
Dioa,Dopa
8
Z
S
I
5-),(Ss5-2)
Mating
Switch
Crag,
C224
&
GND
Plas
oe
ee
ris
te
=
3.
LAST
NO
06,0)
.Ce,
Rrs2
§
§
|
FUSE
TB0Om
z
I
©206,D9,Re,
Ross
S RY FUSE (06A) | £127
v i £227
| 70 MOTOR
Ce
|
!
c|
|
EH.
Sa-)
|
ome) (FUSE Teoma
Cs PSC
at
z
;
REC
ay,
)
Ac
Seconoary
Switch
is
not
vsed
8 10.5 V (Dolby OM) |
ms
8
110V
(Dolby
OFF)
!
& Ny y | i
O
000 Yor KK optoaey)
Si0g
a
Q
|
|
J0.6V (REC) H H
MEBV (PLAY) EXD, |
| |
!
4
(FOR MVD)