Sony BM-87-DST Service manual
BM-87DST
SERVICE MANUAL
Ver 1.0 2000.01
SPECIFICATIONS
US Model
Model Name Using Similar Machanism NEW
T ape Transport Mechanism Type MB-87-59
MICROFILM
DICTATOR/ TRANSCRIBER
SECTION 1
SERVICING NOTE
TABLE OF CONTENTS
Specifications ........................................................................... 1
1. SERVICING NOTE ....................................................... 2
2. GENERAL
Features .............................................................................. 3
Precautions ......................................................................... 3
Operation Flow Chart ........................................................ 4
Location and Function of Controls .................................... 5
Preparation ......................................................................... 6
Dictating............................................................................. 7
Transcribing ....................................................................... 9
Erasing ............................................................................. 11
Alarm System .................................................................. 12
Telephone Recording ....................................................... 12
3. DISASSEMBLY
3-1. Cabinet (Rear) Assy , Cabinet (Front) ASSY ........... 13
3-2. Main Board, Connecter (12P) Board ........................ 13
3-3. LED Board................................................................ 14
3-4. Mechanism Deck ...................................................... 14
3-5. Servo Board, “Head Magnetic (REC/PB/Erase)
(HRP901)”, Motor (F/R) ASSY (M902).................. 15
3-6. Belt (FWD), Belt (F/R)............................................. 15
3-7. Motor (FWD) ASSY(M901) .................................... 16
NOTES FOR REPAIRING
1. POWER (S101) Switch
The POWER switch is not for turning ON/OFF the power
source. Pay attention when repairing even the POWER
switch is turned off.
• The states when turning off the POWER switch are as
follows.
a. Motors (M901, 902) will be stopped.
b. Plungers (PM901 to 903) will be turned off.
c. Amplifier output will be cut-off by muting on.
The above items from “a” to “c” are controlled by the
microcomputer which makes the pin 38 of IC109
(microcomputer) become Low level.
2. Be careful the short circuit when repairing since the power
supply circuit does not have any protection devices.
Please note that the current shut down (D108) will be work
when the power connected to the opposite way.
3. Crack of Flywheel Gear and Cam Gear
Do not turn the Flywheel counterclockwise.
The flywheel gear and cam gear may be crack when turn the
flywheel counterclockwise.
cam gear
4. MECHANICAL ADJUSTMENTS .......................... 17
5. ELECTRICAL ADJUSTMENTS............................ 18
6. DIAGRAMS
6-1. Explanation of IC Terminals ..................................... 19
6-2. Block Diagram.......................................................... 21
6-3. Printed Wiring Boards (Servo Section) .................... 23
6-4. Schematic Diagram (Servo Section)......................... 25
6-5. Printed Wiring Boards (Main Section) ..................... 28
6-6. Schematic Diagram (Main Section) ......................... 31
7. EXPLODED VIEWS
7-1. Cabinet Section......................................................... 35
7-2. Mechanism Deck Section (1) (MB-87-59) ............... 36
7-3. Mechanism Deck Section (2) (MB-87-59) ............... 37
8. ELECTRICAL PARTS LIST............................. 38
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE WITH
MARK 0ON THE SCHEMATIC DIAGRAMS 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.
motor (FWD) (M901)
flywheel
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be damaged by heat.
– 2 –
SECTION 2
GENERAL
This section is extracted from
instruction manual.
– 3 –
– 4 –
– 5 –
– 6 –
– 7 –
– 8 –
– 9 –
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