DOWNLOAD Sony TCM-900DV Service Manual ↓ Size: 2.17 MB | Pages: 32 in PDF or view online for FREE

Model
TCM-900DV
Pages
32
Size
2.17 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
tcm-900dv.pdf
Date

Sony TCM-900DV Service Manual ▷ View online

5
TCM-900DV
6
Washer 
5
Washer (stopper N) 
9
Screws (M1.4)
0
HRPE901
    (REC/PB/ERASE head)
6
Washer 
5
Washer (stopper N) 
3
M601 (Capstan/reel motor)
2
Screws (M1.4)
4
Pulley (reverse)
8
Washer 
8
Washer 
7
Fly ASSY,Capstan
7
Fly ASSY,Capstan
1
Belt (AR)
Attaching belt (AR)
z
2-5. SW BOARD
2-4. BELT (AR), M601 (CAPSTAN/REEL MOTOR),
       HRPE901 (REC/PB/ERASE head)
Cover, cassette lid
SW board
Lever assy, FWD return
Cassette lid assy
1
Screws (+B1.7X 3) 
Lead Wires (from SP901)
Lead wires ( from MIC901)
4
Remove solder ( two places)
3
Remove solder ( two places)
5
Flexible board 
          ( from LCD901) 
6
2
TCM-900DV
6
3-2. ELECTRICAL ADJUSTMENTS
• Standard Level
Input signal level
MIC
– 60dBs
Output signal level
EAR (EARPHONE)
1.6k
Ω, –22,4dBs
• Test Tape
Type
Signal
Used for
WS-48A
3kHz, 0dB
           tape speed adjustment
   0dB=0.775V
Setting :
VOL Control (RV301)
: mechanical mid
REC TIME (S903)
: normal(4.8cm/s)
SPEED CONTROL (RV901): normal (center click)
DPC(MANUAL) Adjustment
Setting :
DPC(S904) switch
: MANUAL
Tape speed
: 4.8cm/s
Mode
: PLAY
Procedure :
[MAIN BOARD](SIDE B)
1. Connect the freguency counter to TP47 and TP8(GND).
2. Adjust RV401 so that the freguency at TP47 becomes 220 Hz.
Standard value : 117 to 223 Hz
Adjustment Location : Main board (See page 7)
SECTION 3
ADJUSTMENTS
3-1. MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured alcohol-moistened
swab  :
record/playback/erase head
pinch roller
rubber belts
capstan
2. Demagnetize the record/playback head with a head demagne-
tizer. (Do not bring the head demagnetizer close to the erase
head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power sup-
ply voltage unless otherwise noted.
6. Power supply voltage : 3V DC.
Torque Measurement
Mode
Torque Meter
Meter Reading
Forward
CQ-102C
1.97 to 3.92 mN • m
(20 to 40 g • cm)
(0.28 to 0.55 oz• inch)
Forward
CQ-102C
0.05 to 0.49 mN • m
(0.5 to 5.0 g • cm)
(0.007 to 0.07 oz• inch)
Fast Forward
more than 4.90 mN • m
and Rewind
CQ-201B
(50 g • cm)
(0.7 oz• inch)
Tape Tension  Measurement
Mode
Tension Meter
Meter Reading
Forward
CQ-403A
more than 50g
( 1.77oz)
/Reverse
1
36
25
48
35
15
40
12
30
24
20
37
45
5
10
13
L401
IC401
R409
C420
C422
R417
R416
C416
R405
R402
R406
R407
RV401
C401
304
8
C410
C402
C403
C414
C415
R403
R404
R401
C412
C413
C407
TP46
TP82
TP47
TP51
TP63
+
frequency counter
TP47
TP8(GND)
Note: Adjust before the tape speed adjustment
TCM-900DV
7
Tape Speed Adjustment
Procedure :
TP8(GND)
TP47
RV601
RV401
DPC (MANUAL) Adjustment
RV602
RV603
RV604
IC401
1
48
Tape Speed
Adjustment
[MAIN BOARD] (B side)
Adjustment Location : Main board (B side)
set
test tape
WS-48A
(3kHz, 0dB)
10k
EAR (earphone) jack (J102)
digital frequency 
counter
Note: Adjust on both sides DIR switch (S701) “ b  “ and “ B “.
1. Set DPC switch (S904) to OFF, PITCH CONTROL switches
(S910, 911) to the center and play the test tape WS-48A.
2. Set REC TIME switch (S903) to NORMAL (4.8cm/s) and turn
SPEED CONTROL knob (RV901) fully to FAST.
3. Adjust RV601 so that the reading on the frequency counter
becomes 6000Hz.
4. Turn SPEED CONTROL knob (RV901)  to the center and adjust
RV602 so that the reading on the frequency counter becomes
3010Hz.
5. Set REC TIME switch (S903) to DOUBLE (2.4cm/s) and turn
SPEED CONTROL knob (RV901) fully to the center.
6. Adjust RV603 so that the reading on the frequency counter
becomes 1505Hz.
7. Turn SPEED CONTROL knob (RV901) fully to SLOW.
8. Adjust RV604 so that the reading on the frequency counter
 becomes 1050Hz.
9. Turn SPEED CONTROL knob (RV901) fully to FAST and
confirm the reading on the frequency counter becomes approx.
3010Hz.
10. Set REC TIME switch (S903) to NORMAL (4.8cm/s) and turn
SPEED CONTROL knob (RV901) fully to SLOW.
11. Confirm the reading on the frequency counter becomes approx.
1505Hz.
TCM-900DV
8
z
 Waveforms
2
4
5
IC301   ql
IC401   ej
IC901   2
PB mode
VOLT/DIV : 1 V AC
TIME/DIV : 0.2 
µsec
PB (DPC AUTO) mode
VOLT/DIV : 1 V AC
TIME/DIV : 1 
µsec
REC/PB mode
VOLT/DIV : 1 V AC
TIME/DIV : 10 
µsec
– MAIN SECTION (1/3) –
– MAIN SECTION (3/3) –
– SW SECTION –
– MAIN SECTION (2/3) –
3.6 Vp-p
0.25 
µsec
3.8 Vp-p
1.30 
µsec
25 
µsec
3.6 Vp-p
Note on Schematic Diagram: MAIN SECTION
• All capacitors are in 
µF unless otherwise noted.  pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in 
Ω and 
1
/
4
 
W or less unless otherwise
specified.
f
: internal component.
• C : panel designation.
 Note:
 Note:
 The components identi-
 Les composants identifiés
 fied by mark 0 or dotted  par une marque 0 sont cri-
 line with mark 0 are cri-  tiques pour la sécurité.
 tical for safety.
 Ne les remplacer que par
 Replace only with part
 une piéce portant le
 number specified.
 numéro spécifié.
: B+ Line.
• H : adjustment for repair.
• Power voltage is dc 3V and fed with regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground
under no-signal conditions.
no mark : PLAY (DPC OFF)
(
)
: REC
<
>
: PLAY (DPC AUTO)
• Voltages are taken with a VOM (Input impedance 10 M
Ω).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
E
: PB
a
: REC
3.8 Vp-p
0.25 
µsec
3
IC701   wh
REC/PB mode
VOLT/DIV : 1 V AC
TIME/DIV : 0.2 
µsec
SECTION 4
DIAGRAMS
1
T101
REC mode
VOLT/DIV : 5 V AC
TIME/DIV : 5 
µsec
30 Vp-p
20.0 
µsec
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