SONY SLV-M20HF Service Manual

SLV-M20HF

RMT-V250

SERVICE MANUAL

G
j

• Refer to the SERVICE MANUAL of VHS MECHANICAL
ADJUSTMENT
(9-921-647-11)

for MECHANICAL ADJUSTMENTS.

SPECIFICATIONS

US Model

Canadian Model

S MECHANISM

MICROFILM

VIDEO CASSETTE RECORDER

[ NOTE ON REP AIRING HARNESSES BETWEEN AN-16/17

BOARDS AND MG-21 BOARD ]

AN-16 board MG-21 board
CN201 CN002
AN-17 board MG-21 board
CN101 CN001

Be sure to use the original one or equivalent (AWG, length).
If not so, the resonance frequency will be changed.

SAFETY CHECK-OUT

After correcting the original service problem, perform the following
safety checks before releasing the set to the customer.

1. Check the area of your repair for unsoldered or poorly-soldered
connections. Check the entire board surface for solder splashes
and bridges.

2. Check the interboard wiring to ensure that no wires are
"pinched" or contact high-wattage resistors.

3. Look for unauthorized replacement parts, particularly
transistors, that were installed during a previous repair . Point
them out to the customer and recommend their replacement.

4. Look for parts which, though functioning, show obvious signs
of deterioration. Point them out to the customer and
recommend their replacement.

5. Check the line cord for cracks and abrasion.
Recommend the replacement of any such line cord to the
customer.

6. Check the B+ voltage to see it is at the values specified.

7. Check the antenna terminals, metal trim, "metallized" knobs,
screws, and all other exposed metal parts for AC leakage.
Check leakage as described below.

T o Exposed Metal

Parts on Set

AC

0.15

µ

F

1.5 k

Ω

Voltmeter
(0.75 V)

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
TW-540A. Follo w the manufacturers' instructions to use these
instruments.

2. A battery-operated A C 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 v oltmeter. The "limit" indication
is 0.75V, so analog meters must have an accurate lo w v oltage
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 A C range are suitable. (See
Fig. A)

Earth Ground

Fig. A. Using an A C v oltmeter to check A C leakage.

SAFETY-RELATED COMPONENT WARNING!!

COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE WITH
MARK ! ON 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.

ATTENTION AU COMPOSANT AYANT RAPPORT

À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFÉS PAR UNE MARQUE ! SUR LES
DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES PIÈCES SONT
CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE
REMPLACER CES COMPOSANTS QUE PAR DES PIÈSES SONY
DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPÉMENTS PUBLIÉS PAR SONY.

— 2 —

TABLE OF CONTENTS

SERVICE NOTE

1. ERROR CODE INDICATION··········································· 5

1. GENERAL

Basic Operations

Playing a tape·········································································1-1
Recording TV programs ························································1-1
Locating a channel using the channel list ······························1-2
Recording TV programs using VCR Plus+ ···························1-3
Setting the timer manually·····················································1-3

Additional Operations

Playing/searching at various speeds ······································1-4
Searching for a selected point on the tape ·····························1-5
Skip-searching automatically·················································1-5
Creating a favorite channel list ··············································1-6
Recording TV programs using the quick timer ·····················1-6
Checking/changing/cancelling the manual timer settings ·····1-6
Recording stereo and bilingual programs ······························1-7
Searching using the index function········································1-8
Adjusting the picture ····························································· 1-8
Changing menu options ·························································1-8
Editing with another VCR ·····················································1-9

SmartFile function

About the SmartFile function ················································1-9
Recording using the SmartFile function ······························ 1-10
Selecting and playing a program ·········································1-11
Checking the contents of a tape ··········································· 1-11
Labelling a recorded program and tape ·······························1-11
Protecting a recorded program·············································1-13
Erasing the data of an unwanted program ···························1-13
Storing program data from the DSS receiver
(Program Data Download)···················································1-13

GUIDE Plus+ system

About the GUIDE Plus+ system··········································1-14
Overview of the GUIDE Plus+ menu ··································1-15
Using the Grid menu····························································1-15
Using the Sort menu ····························································1-16
Using the Schedule menu ····················································1-17
Using the Editor menu ························································· 1-18
Using the Demo menu ·························································1-19

Additional Information

Troubleshooting ···································································1-19
Index to parts and controls···················································1-20

2. DISASSEMBLY

2-1. UPPER CASE,

FRONT PANEL BLOCK ASSEMBLY ··························2-1
2-2. FR-139, DM-81, AJ-2, AN-17 BOARDS ·······················2-1
2-3. MG-21 BOARD, REAR PANEL ····································2-1
2-4. POWER BLOCK, MA-335 BOARD

(WITH S MECHANISM DECK) ···································2-2
2-5. AN-16 BOARD, S MECHANISM DECK ·····················2-2
2-6. INTERNAL VIEWS························································2-3
2-7. CIRCUIT BOARDS LOCATION ···································2-4

3. BLOCK DIAGRAMS

3-1. OVERALL BLOCK DIAGRAM ····································3-1
3-2. VIDEO BLOCK DIAGRAM ··········································3-3
3-3. SERVO/SYSTEM CONTROL BLOCK DIAGRAM ·····3-5
3-4. AUDIO BLOCK DIAGRAM ··········································3-7
3-5. MODE CONTROL BLOCK DIAGRAM ·······················3-9
3-6. TUNER BLOCK DIAGRAM ·······································3-11
3-7. POWER SUPPLY BLOCK DIAGRAM ·······················3-13

4. PRINTED WIRING BOARDS AND

SCHEMATIC DIAGRAMS

4-1. FRAME SCHEMATIC DIAGRAM································4-1

4-2. PRINTED WIRING BOARDS AND

SCHEMATIC DIAGRAMS ············································ 4-3

• MA-335 (REC/PB AMP, VIDEO, SERVO/SYSTEM
CONTROL, AUDIO, TUNER)
PRINTED WIRING BOARD ·························4-3

• MA-335 (REC/PB AMP) SCHEMATIC DIAGRAM ··4-5

• MA-335 (VIDEO, NORMAL AUDIO)
SCHEMATIC DIAGRAM ······························4-8

• MA-335 (SERVO/SYSTEM CONTROL)
SCHEMATIC DIAGRAM ····························4-11

• MA-335 (ON SCREEN DISPLAY)
SCHEMATIC DIAGRAM ····························4-15

• MA-335 (DSF) SCHEMATIC DIAGRAM················4-17

• MA-335 (AFM AUDIO)
SCHEMATIC DIAGRAM ····························4-19

• MA-335 (TUNER) SCHEMATIC DIAGRAM··········4-21

• MA-335 (POWER SUPPLY)
SCHEMATIC DIAGRAM ····························4-23

• MA-335 (AV-BUS) SCHEMATIC DIAGRAM ·········4-25

• FR-139 (MODE CONTROL)
PRINTED WIRING BOARD ·······················4-27

• FR-139 (MODE CONTROL)
SCHEMATIC DIAGRAM ····························4-29

• DM-81 (OPERATION SWITCHES)
PRINTED WIRING BOARD AND
SCHEMATIC DIAGRAM ····························4-31

• AJ-2 (LINE-2 IN)
PRINTED WIRING BOARD AND
SCHEMATIC DIAGRAM ····························4-32

• AN-16 (INNER SMART FILE SENSOR/WRITER),
AN-17 (FRONT SMART FILE SENSOR)
PRINTED WIRING BOARDS AND
SCHEMATIC DIAGRAMS··························4-33

• MG-21 (CONDUCTOR SIDE) (SMART FILE)
PRINTED WIRING BOARD ·······················4-35

• MG-21 (COMPONENT SIDE) (SMART FILE)
PRINTED WIRING BOARD ·······················4-37

• MG-21 (SMART FILE)
SCHEMATIC DIAGRAM ····························4-39

• MG-21 (GUIDE PLUS) (SMART FILE)
SCHEMATIC DIAGRAM ····························4-41

• MG-21 (VIDEO ENCODER) (SMART FILE)
SCHEMATIC DIAGRAM ····························4-43

• POWER BLOCK SR821 (SWITCHING REGULATOR)
PRINTED WIRING BOARD AND
SCHEMATIC DIAGRAM ····························4-45

5. INTERFACE, IC PIN FUNCTION
DESCRIPTION

5-1. SYSTEM CONTROL —

VIDEO BLOCK INTERFACE
(MA-335 BOARD IC161)···············································5-1

5-2. SYSTEM CONTROL —

SERVO PERIPHERAL CIRCUIT INTERFACE
(MA-335 BOARD IC161)···············································5-1

5-3. SYSTEM CONTROL —

MECHANISM INTERFACE
(MA-335 BOARD IC161)···············································5-2

5-4. SYSTEM CONTROL —

SYSTEM CONTROL PERIPHERAL
CIRCUIT INTERFACE (MA-335 BOARD IC161) ·······5-2

5-5. SYSTEM CONTROL —

AUDIO BLOCK INTERFACE
(MA-335 BOARD IC161)···············································5-2

5-6. SERVO/SYSTEM CONTROL MICROPROCESSOR

PIN FUNCTIONS (MA-335 BOARD IC161)················5-3

5-7. TUNER/TIMER MODE CONTROL PIN FUNCTIONS

(FR-139 BOARD IC460) ················································5-4

— 3 —

6. ADJUSTMENTS

6-1 MECHANICAL ADJUSTMENTS ·································6-1
6-2. ELECTRICAL ADJUSTMENTS ···································6-1
2-1. PREPARATION BEFORE ADJUSTMENT···················6-1
2-1-1.Equipment Required ························································6-1
2-1-2.Equipment Connection ····················································6-1
2-1-3.Input Signal Check ··························································6-1
2-1-4.Alignment Tape ·······························································6-1
2-1-5.Input/Output Levels and Impedance ·······························6-2
2-1-6.Adjustment Sequence ······················································6-2
2-2. POWER SUPPLY CHECK ·············································6-2
2-2-1.Output Voltage Check (MA-335 Board) ·························6-2
2-3. SERVO SYSTEM CHECK ·············································6-3
2-3-1.RF Switching Position/

AF Switching Position Adjustments (MA-335 Board) ···6-3
2-4. VIDEO SYSTEM CHECKS ··········································· 6-4
2-4-1.X’tal OSC Check (MA-335 Board)································· 6-4
2-4-2.SYNC AGC Check (MA-335 Board)······························6-4
2-4-3.Recording Y Level Check (MA-335 Board) ···················6-4
2-4-4.Recording Chroma Level Check (MA-335 Board) ·········6-5
2-4-5.Playback Level Check (MA-335 Board) ·························6-5
2-5. AUDIO SYSTEM ADJUSTMENT·································6-5
2-5-1.ACE Head Adjustment ····················································6-5
2-5-2.E-E Output Level Check ·················································6-5
2-5-3.Overall Output Level and Distortion Factor Check·········6-6
2-5-4.Overall Noise Level Check··············································6-6
2-6. TUNER SYSTEM ADJUSTMENT································ 6-6
2-6-1.Separation Adjustment (MA-335 Board) ························6-6
2-7. ADJUSTING PARTS LOCATION DIAGRAM ·············6-8

7. REPAIR PARTS LIST

7-1. EXPLODED VIEWS ······················································7-1
7-1-1.FRONT PANEL ASSEMBLY AND UPPER CASE

SECTION ········································································7-1
7-1-2.CHASSIS SECTION·······················································7-2
7-1-3.MECHANISM DECK-1 ·················································7-3
7-1-4.MECHANISM DECK-2 ·················································7-4
7-1-5.MECHANISM DECK-3 ·················································7-5
7-2. ELECTRICAL PARTS LIST ··········································7-6

— 4 —

SERVICE NOTE

1. ERROR CODE INDICATION

• Error codes are indicated using the lower 5 digits in the fluorescent display tube.
“At this time, Colon “:” between character is not indicated.”

Mode code indication when the error has occurred.

Error code

ERROR CODE

0 No error
1 Cam encoder error Loading direction
2 Cam encoder error Unloading direction
3 T reel error
4 S reel error
5 Capstan error
6 Drum error
7 Error on initializing
8 Cassette loading error
9 Reserve

SLV-M20HF

MODE CODE

0 Power-on eject 10 FWD x1 20 REW play
1 Power-on initial 11 FWD x2 21 Cas. loading
2 Power-off eject 12 CUE 22 Tape loading
3 Power-off stop 13 PB-pause 23 Power-off loading
4 FF 14 RVS-pause 24 Mecha. error (Power on)
5 REW 15 RVS x1 25 Power-on eject initial
6 REC 16 RVS x2 26 Power-off eject initial
7 REC- pause 17 REV 27 APC REC
8 Power-on stop 18 Power-off initial 28 Cas. loading
9 PB 19 Mecha. error (Power off) (No auto PB check)

— 5 —

SECTION 1

GENERAL

SLV-M20HF

This section is extracted
from instruction manual.

1-1

1-2

1-3

1-4

1-5

1-6

1-7

1-8

1-9

1-10

1-11

1-12

1-13

1-14

1-15

1-16

1-17

1-18

1-19

1-20

1-21E

SECTION 2

)

Front panel assembly

1

Screws (B2.6 × 8)

2

DM-81 board

2

FR-139 board

3

Flat cable
From CN140 on
FR-139 board

3

Frexible board
From CN441 on
DM-81 board

1

Screws (B2.6 × 8)

6

Screw (B2.6 × 8)

4

Screw (B2.6 × 8)

8

AJ-2 board

7

JK ground plate

9

AN-17 board

5

Antenna (large) shield plate <Note>

Note : When peeling off the antenna (large) shield plate,
be sure to apply it to the original position on the
AJ-2 board.
If not so, the resonance level of AN-17 board
becomes small.

DISASSEMBLY

NOTE: Follow the disassembly procedure in the numerical order given.

2-1. UPPER CASE, FRONT PANEL BLOCK ASSEMBLY

3

Connector
From CN423 on
MA-335 board

4

3

Flat cable
From CN162 on
MA-335 board

Hooks

1

Screws (case)

2

Upper case

SLV-M20HF

1

Screws (case

5

Front panel

block assembly

4

Hooks

2-2. FR-139, DM-81, AJ-2, AN-17 BOARDS

2-3. MG-21 BOARD, REAR PANEL

1

Screws

4

Hooks

4

Hooks

2

MG-21 board

4

Hooks

4

Hooks

5

Rear panel

4

Hooks

3

2-1

Release cable stopper

from rear panel