Funai 31A-450 Service Manual
SERVICE MANUAL
Main Section
I Specifications
I Preparation for Servicing
I Adjustment Procedures
I Schematic Diagrams
I CBA’s
I Exploded views
I Parts List
When servicing the deck
mechanism, refer to MK14 Deck
Mechanism Section.
Deck Mechanism Part No.:
N25C0FL
VIDEO CASSETTE RECORDER
31A-450
31C-450
SECAMPAL
MAIN SECTION
VIDEO CASSETTE RECORDER
31A-450/31C-450
Sec. 1: Main Section
I Specifications
I Preparation for Servicing
I Adjustment Procedures
I Schematic Diagrams
I CBA’s
I Exploded Views
I Par ts L ist
TABLE OF CONTENTS
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1-1
Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2-1
Standard Notes for Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3-1
Preparation for Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4-1
Cabinet Disassembly Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5-1
Electrical Adjustment Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6-1
How to Initialize the VCR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7-1
Function Indicator Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8-1
Block Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9-1
Schematic Diagrams / CBA’s and Test Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10-1
Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11-1
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12-1
IC Pin Function Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13-1
Lead Identifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14-1
Exploded Views. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15-1
Mechanical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16-1
Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17-1
SPECIFICATIONS
Description Unit Minimum Nominal Maximum Remark
1. Video
1-1. Video Output (PB) Vp-p 0.8 1.0 1.2 FL6A
1-2. Video Output (R/P) Vp-p 0.8 1.0 1.2
1-3. Video S/N Y (R/P) dB 40 45
1-4. Video Color S/N AM (R/P) dB 37 41 SP Mode
1-5. Video Color S/N PM (R/P) dB 30 36 SP Mode
1-6. Resolution (PB) Line 230 245 SP Mode
2. Servo
2-1. Jitter Low µsec 0.07 0.12 SP Mode
2-2. Wow & Flutter % 0.3 0.5 SP Mode
3. Normal Audio
3-1. Output (PB) dBV -9 -6 -3 SP Mode
3-2. Output (R/P) dBV -9 -6 -1.5 SP Mode
3-3. S/N (R/P) dB 36 41 SP Mode
3-4. Distortion (R/P) % 1.0 4.0 SP Mode
3-5. Freq. resp (R/P) at 200Hz dB -7 -4 SP Mode
(-20dB ref. 1kHz) at 6kHz dB -10 -4 SP Mode
SP Mode,
W/O Burst
4. Tuner
4-1. Video output Vp-p 0.8 1.0 1.2 E-E Mode
4-2. Video S/N dB 39 42 E-E Mode
4-3. Audio output dB -10 -6 -2 E-E Mode
4-4. Audio S/N dB 40 46 E-E Mode
Note: Nominal specs represent the design specs. All units should be able to approximate these – some will
exceed and some may drop slightly below these specs. Limit specs repres ent the absolute worst con dition that
still might be considered acceptable; In no case should a unit fail to meet limit specs.
1-1-1 HM340SP
IMPORTANT SAFETY PRECAUTIONS
Product Safety Notice
Some electrical and mechanical parts have special
safety-related characteristic s which are often not evident from visual inspection, nor can the protection
they give necessarily be obtained by replacing them
with components rated for higher voltage, wattage,
etc. Parts that have special s afety characteristics are
identifi ed b y a ! on schematics and in parts lists. Use
of a substitute replacement that does not have the
same safety characteristics as the recommended
replacement part might create shock, fire, and/or other
hazards. The Product’s Safety is under review continuously and new instructions are issued whenever
appropriate. Prior to shipment from the factory, our
products are carefully inspected to confirm with the
recognized product safety and electr ical codes of the
countries in which they are to be sold. However, in
order to maintai n suc h c omp li anc e, it is e qual ly imp or tant to implement the following precautions when a set
is being serviced.
Precautions during Servicing
A. Parts identified by the ! symbol are critical for
safety. Replace only with part number specified.
B. In addition to safety, other parts and assemblies
are specified for conformance with regulations
applying to spur ious radi ation. Thes e must also be
replaced only with specified replacements.
Examples: RF conver ters, RF cables, noise blocking capacitors, and noise blocking filters, etc.
C. Use specified internal wiring. Note especially:
1)Wires covered with PVC tubing
2)Double insulated wires
3)High voltage leads
D. Use specified insulating materials for hazardous
live parts. Note especially:
1)Insulation tape
2)PVC tubing
3)Spacers
4)Insulators for transistors
E. When replacing AC primary side components
(transformers, power cord, etc.), wrap ends of
wires securely about the terminals before soldering.
F. Observe that the wires do no t co ntac t he at prod uc -
ing parts (heatsink s, oxide metal film resist ors, fusible resistors, etc.).
G. Check that replaced wires do not contact sharp
edges or pointed parts.
H. When a power cord has b een replac ed, check that
5 - 6 kg of force in any direction will not loosen it.
I. Also check areas surrounding repaired locations.
J. Be careful that foreign objects (screws, solder
droplets, etc.) do not remain inside the set.
K. Crimp type wire connector
The power transformer uses crimp type connectors
which connect the power cord and the primary side
of the transformer. When replacing the transformer,
follow these steps carefully and precisely to prevent shock hazards.
Replacement procedure
1)Remove the old connector by cutting the wires at a
point close to the connector.
Important: Do not re-use a connector. (Discard it.)
2)Strip about 15 mm of the insu lation from the ends
of the wires. If the wires are stranded, twist the
strands to avoid frayed conductors.
3)Align the lengths of the wires to be connected.
Insert the wires fully into the connector.
4)Use a crimping tool to crimp the metal sleeve at its
center. Be sure to crimp fully to the comp lete closure of the tool.
L. When connecting or disconnecting the internal
connectors, first, disconne ct the AC plug from the
AC outlet.
1-2-1 U31P_ISP
Safety Check after Servicing
Examine the area surrounding the repaired location
for damage or deterioration. Observe that screws,
parts, and wires have been returned to their original
positions. Afterwards, do the following tests and confirm the specified values to verify compliance with
safety standards.
1. Clearance Distance
When replacing primary circuit components, confirm
specified clearance dista nce (d) and (d’) between soldered terminals, and between terminals and surrounding metallic parts. (See Fig. 1)
Table 1 : Ratings for selected area
AC Line Voltage Clearance Distance (d), (d’)
220 to 240 V
Note: This table is unofficial and for reference only.
Be sure to confirm the precise values.
≥ 3mm(d)
≥ 6 mm(d’)
2. Leakage Curre nt Test
Confirm the specified (or lower) leakage current
between B (earth ground, power cord plug prongs)
and externally exposed accessible parts (RF terminals, antenna terminals, video and audio input and
output terminals, microphone jacks, earphone jacks,
etc.) is lower than or equal to the specified value in the
table below.
Measuring Method (Power ON) :
Insert load Z between B (earth ground, power cord
plug prongs) and exposed accessible parts. Use an
AC voltmeter to measure across t he ter minals of l oad
Z. See Fig. 2 and the following table.
Chassis or Secondary Conductor
Primary Circuit
d' d
Exposed Accessible Part
Z
One side of
B
Power Cord Plug Prongs
AC Voltmeter
(High Impedance)
Fig. 1
Fig. 2
Table 2: Leakage current ratings for selected areas
AC Line Voltage Load Z Leakage Current (i)
2kΩ RES.
Connected in
parallel
220 to 240 V
50kΩ RES.
Connected in
parallel
Note: This table is unofficial and for reference only. Be sure to confirm the precise values.
i≤0.7mA AC Peak
i≤2mA DC
i≤0.7mA AC Peak
i≤2mA DC
1-2-2 U31P_ISP
One side of power cord plug
prongs (B) to:
RF or
Antenna terminals
A/V Input, Output
STANDARD NOTES FOR SERVICING
Circuit Board Indications
1. The output pin of the 3 pin Regulator ICs is
indicated as shown.
Top View
Out
2. For other ICs, pin 1 and every fifth pin are
indicated as shown.
Pin 1
3. The 1st pin of every male connector is indicated as
shown.
Pin 1
Input
In
Bottom View
5
10
Pb (Lead) Free Solder
When soldering, be sure to use the Pb free solder.
How to Remove / Install Flat Pack-IC
1. Removal
With Hot-Air Flat Pack-IC Desoldering Machine:
1. Prepare the hot-air flat pack-IC desoldering
machine, then apply hot air to the Flat Pack-IC
(about 5 to 6 seconds). (Fig. S-1-1)
Fig. S-1-1
2. Remove the flat pack-IC with tweezers while
applying the hot air.
3. Bottom of the flat pa ck-IC is fixed with glue to the
CBA; when removing entire flat pack-IC, first apply
soldering iron to center of the flat pack-IC and heat
up. Then remove (glue will be melted). (Fig. S-1-6)
4. Release the flat pack-IC from the CBA using
tweezers. (Fig. S-1-6)
CAUTION:
1. The Flat Pack-IC shape may differ by models. Use
an appropriate hot-air flat pack-IC desoldering
machine, whose shape matches that of the Flat
Pack-IC.
2. Do not supply hot air to the c hip par ts around the
flat pack-IC for over 6 seconds because damage
to the chip parts may occur. Put masking tape
around the flat pack-IC to protec t other pa r ts from
damage. (Fig. S-1-2)
1-3-1 VCRP_SN
3. The flat pack-IC on the CBA is affixed with glue, so
be careful not to break or dam age the foil of ea ch
pin or the solder lands under the IC when
removing it.
With Soldering Iron:
1. Using desoldering braid, remove the solder from
all pins of the flat pack-IC. When you use solder
flux which is applie d to all pi ns of the fl at pack-IC,
you can remove it easily. (Fig. S-1-3)
CBA
Masking
Tape
Tweezers
Hot-air
Flat Pack-IC
Desoldering
Machine
Flat Pack-IC
Fig. S-1-2
Flat Pack-IC
Desoldering Braid
Soldering Iron
Fig. S-1-3
2. Lift each lead of the flat pack-IC upward one by
one, using a shar p pin or wi re to which s older will
not adhere (iron wire). W hen hea tin g the pins, use
a fine tip soldering iron or a hot air desoldering
machine. (Fig. S-1-4)
Sharp
Pin
Fine Tip
Soldering Iron
3. Bottom of the flat pa ck-IC is fixed with glue to the
CBA; when removing entire flat pack-IC, first apply
soldering iron to center of the flat pack-IC and heat
up. Then remove (glue will be melted). (Fig. S-1-6)
4. Release the flat pack-IC from the CBA using
tweezers. (Fig. S-1-6)
Fig. S-1-4
1-3-2 VCRP_SN
With Iron Wire:
1. Using desoldering braid, remove the solder from
all pins of the flat pack-IC. When you use solder
flux which is ap plied to all pins of the flat pack-IC,
you can remove it easily. (Fig. S-1-3)
2. Affix the wire to a workbench or solid mounting
point, as shown in Fig. S-1-5.
3. While heating the pins using a fine tip soldering
iron or hot air blower, pull up the wire as the solder
melts so as to lift the IC leads from the CBA
contact pads as shown in Fig. S-1-5.
4. Bottom of the f lat pack-IC is fixed with glue to the
CBA; when removing entire flat pack-IC, first apply
soldering iron to center of the flat pack-IC and heat
up. Then remove (glue will be melted). (Fig. S-1-6)
5. Release the flat pack-IC from the CBA using
tweezers. (Fig. S-1-6)
Note: When using a soldering iron, care must be
taken to ensure that the flat pack-IC is not
being held by glue. When the flat pack-IC is
removed from the CBA, handle it gently
because it may be damaged if force is applied.
Hot Air Blower
2. Installation
1. Using desoldering braid, remove the solder from
the foil of each pin of the flat pack-IC on the CBA
so you can install a r ep la cem ent fl at p ack-IC mo re
easily.
2. The “●” mar k on the flat pack-IC indicates pin 1.
(See Fig. S-1-7.) Be su re thi s mar k m atche s the 1
on the PCB when positioni ng for installa tion. Then
presolder the four corners of th e fl at pa ck-IC. (See
Fig. S-1-8.)
3. Solder all pins of the flat pack-IC. Be sure that
none of the pins have solder bridges.
Example :
Pin 1 of the Flat Pack-IC
is indicated by a " " mark.
Fig. S-1-7
To Solid
Mounting Point
CBA
Tweezers
Iron Wire
Soldering Iron
Fig. S-1-5
Fine Tip
Soldering Iron
Flat Pack-IC
or
Presolder
Flat Pack-IC
CBA
Fig. S-1-8
Fig. S-1-6
1-3-3 VCRP_SN
Instructions for Handling Semiconductors
Electrostatic breakdown of the semi-conductors may
occur due to a potential difference caused by
electrostatic charge during unpacking or repair work.
1. Ground for Human Body
Be sure to wear a grounding band (1 MΩ) that is
properly grounded to remove any static el ectric ity that
may be charged on the body.
2. Ground for Workbench
Be sure to place a c onductive sheet or copper plate
with proper grounding (1 MΩ) on the workbench or
other surface, where the semi-conductors are to be
placed. Because the static electricity charge on
clothing will not escape through the body grounding
band, be careful to avoid contacting semi-conductor s
with your clothing.
<Incorrect>
<Correct>
1MΩ
CBA
Grounding Band
1MΩ
CBA
Conductive Sheet or
Copper Plate
1-3-4 VCRP_SN
PREPARATION FOR SERVICING
How to Enter the Service Mode
About Optical Sensors
Caution:
An optical sensor system is used for the Tape Start
and End Sensors on this equipment. Carefully read
and follow the instructions below. Otherwise the unit
may operate erratically.
What to do for preparation
Insert a tape into the Deck Mechanism Asse mbly and
press the PLAY button. The tape will be loaded into
the Deck Mechanism Assembly. Make sure the power
is on, connect TP507 (S-INH) to GND. T his will stop
the function of Tape Start Sensor, Tape End Sensor
and Reel Sensors. (If these TPs ar e c on nected before
plugging in the unit, the function of the sensors will
stay valid.) See Fig. 1.
Note: Because the Tape End Sensors are inactive, do
not run a tape al l t he way to the start or the end of the
tape to avoid tape damage.
Q505
Q504
TP507
S-INH
Fig. 1
1-4-1 HM4N0PFS
CABINET DISASSEMBLY INSTRUCTIONS
1. Disassembl y Flowchart
This flowchar t indi cates the di sass embly ste ps to ga in
access to item(s) to be serviced. When reassembling,
follow the steps in reverse order. Bend, route, and
dress the cables as they were originally.
[1] T op Case
[2] Front Assembly
[3] VCR Chassis Unit
[4] Jack CBA
[5] Deck Assembly
[6] Main CBA
[7] Cylinder Shield
2. Disassembl y Method
REMOVAL
ID/
LOC
.No.
PART
REMOVE/*UNHOOK/
Fig.
UNLOCK/RELEASE/
No.
UNPLUG/DESOLDER
Note
(1):Identification (location) No. of parts in the figures
(2):Name of the part
(3):Figure Number for reference
(4): Identification of parts to be removed, unhooked,
unlocked, released, unplugged, unclamped, or
desoldered.
P=Spring, L=Locking Tab, S=Screw,
CN=Connector
*=Unhook, Unlock, Release, Unplug, or Desolder
e.g. 2(S-2) = two Screws (S-2),
2(L-2) = two Locking Tabs (L-2)
(5):Refer to “Reference Notes.”
Reference Notes
CAUTION: Locking Tabs (L-1) and (L-2) are fragile.
Be careful not to break them.
1. Remove five Screws (S-2), three Screws (S-3) and
Screw (S-4). Then, slowly lift the VCR Chassis Unit
(Deck Assembly, Jack CBA and Main CBA) up.
2. When reassembling, solder wire jumpers as shown
in Fig. D5.
3. Before installing the Deck Assembly, be sure to
place the pin of LD-SW on Main CBA as shown in
Fig. D6. Then, install the Deck Assembly while
aligning the hole of Cam Gear with the pin of LDSW, the shaft of Cam Gear with the hol e of L D-SW
as shown in Fig. D6.
[1] Top Case D1 7(S-1) -
Front
[2]
Assembly
VCR Chassis
[3]
Unit
[4] Jack CBA D4 Desolder, (S-5) -
Deck
[5]
Assembly
[6] Main CBA D5 ---------- -
Cylinder
[7]
Shield
↓
(1)
↓
(2)
D2 *3(L-1),*4(L-2) -
D3 5(S-2), 2(S-3), (S-4) 1
D5
2(S-6), Desolder 2,3
D6
D5 (S-7) -
↓
(3)
↓
(4)
(S-1)
(S-1)
[1] T op Case
(S-1)
↓
(5)
Fig. D1
1-5-1 HM340DC
(L-2)
[2] Front
Assembly
(S-2)
[3]VCR
Chassis
Unit
(L-1)
(S-3)
(S-2)
(L-2)
(S-2)
[4] Jack CBA
(S-5)
Desolder
Fig. D4
Fig. D2
(S-4)
(S-3)
(S-2)
Fig. D3
1-5-2 HM340DC
[7] Cylinder Shield
FE Head
Cylinder Assembly
(S-7)
ACE Head
Assembly
Pin
SW507
LD-SW
[6] Main CBA
From
FE Head
From
Cylinder
Assembly
(S-6)
TOP VIEW
From
ACE Head
Assembly
[5] Deck
Assembly
[6] Main CBA
(S-6)
From
Capstan Motor
Assembly
Lead with
blue stripe
[5] Deck Assembly
Shaft
Hole
LD-SW
Cam Gear
Hole
Pin
[6] Main CBA
Fig. D6
Printing
Lead with
white stripe
Lead connections of Deck Assembly and Main CBA
Lead with
blue stripe
Desolder
from bottom
side
Fig. D5
1-5-3 HM340DC
ELECTRICAL ADJUSTMENT INSTRUCTIONS
General Note: "CBA" is an abbreviation for
"Circuit Board Assembly."
NOTE:
1.Electri cal adjustm ents are re quired after re placing
circuit components and certain mechanical par ts.
It is impor tant to do these adjustments only after
all repairs and replacements have been completed. Also, do not attempt these adjustments
unless the proper equipment is available.
2.To perfor m these alignment / confirmation procedures, make sure that the tracking control is set in
the center po sition: Press either "CHANNEL L5??" or
"CHANNEL K" button on the remote control unit
first, then the "PLAY" button (Front Panel only).
Te st Equipment Required
1.Oscilloscope: Dual-trace with 10:1 probe,
V-Range: 0.001~50V/Div.,
F-Range: DC~AC-20MHz
2.Alignment Tape (FL6A)
Head Switching Position Adjustment
Purpose:
To determ ine the Head Switching position during
playback.
Symptom of Misadjustment:
May cause Head Switch ing noise or vertical jit ter
in the picture.
Test point Adj.Point Mode Input
J23(V-OUT)
TP502(RF-SW)
GND
Tape
FL6A Oscilloscope
Connections of Measurement Equipment
Main CBA
VR501
(Switching Point)
(MAIN CBA)
Measurement
Equipment
J23
GND
TP502
PLAY
(SP)
6.5H±1H
(416µs±64µs)
Oscilloscope
-----
Spec.
CH1 CH2
Trig. (+)
Figure 1
EXT. Syncronize Trigger Point
CH1
CH2
Reference Notes:
Playback the Alignment tape and adjust VR501 so that
the V-sync front edg e of the CH1 video out put waveform is at the 6.5H±1H (416µs±64µs) delayed position
from the rising edge o f the CH2 head switching pulse
waveform.
1.0H
6.5H+/-1H (416µs+/-64µs)
Switching Pulse
0.5H
V-Sync
1-6-1 FEGVCREA
HOW TO INITIALIZE THE VCR
To put the program back at the factory-default,
initialize the VCR as the following procedure.
1. Make sure that no timer programming is set. If not,
reset all timer programming.
2. Turn the power off.
3. Press the [STOP/EJECT] button and
[CHANNEL K] button on the unit simultaneously
for at least 2 seconds.
4. Release the [STOP/EJECT] button and
[CHANNEL K] button to complete this mode.
1-7-1 HM340INT
FUNCTION INDICATOR SYMBOLS
Note:
The following symbols will appear on the indicator panel to indicate the current mode or operation of the VCR.
On-screen modes will also be momentarily displayed on the tv screen when you press the operation buttons.
Display panel
31A-450
TAPE IN TIMER RECFUNCTIONSTANDBY
31C-450
CASSETTE MINUTERIE ENR. FONCTIONVEILLE
STANDBY
VEILLE
FUNCTION
FONCTION
TAPE IN
CASSETTE
TIMER
MINUTERIE
REC
ENR.
" H "= LED Light on, " L "= LED Light off
MODE INDICATOR ACTIVE
Always " H " during electricity
Power on = " H "
Power off = " L "
Cassette in = " H "
Cassette out = " L "
Timer stand by = " H "
One touch recording = " H "
Timer recording = " H "
General mode = " L "
REC mode = " H "
REC pause
General mode = " L "
Blinks at 0.8Hz interval
1-8-1 HM340FIS
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