Service Manual
Video Cassette
Recorder
VHR-240 series
VHR-250 series
VHR-251 series
VHR-254 series
VHR-24 series
VHR-27 series
Illustration: VHR-250G
prig
PAL
TABLE OF CONTENTS
1. CIRCUIT BOARD LOCATIONS
1-1. MAINBOARDS . .. . . . . . . . . . . . .. .. .. .. .. .. . . . . . . . . . . . . .. .. .. .. . . . . . . . . . . . . . .. . . . . . . . . 1
1-2. LOCATION FOR TAPE PATH ADJUSTMENT . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . 1
2. ELECTRICAL ADJUSTMENT
2-1. PREPARATION . .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. .. . . . . . . . . . . . .. .. .. . . . . . . 2
2-2. SERVO CIRCUIT ADJUSTMENT . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . .. .. .. . . . . . . . . . 4
2-3. VIDEOCIRCUIT ADJUSTMENT . . . . . . . . . . .. .. . . . . . . . . . . . .. .. . . . . . . . . . . . .. .. .. . . ...6
2-4. VIDEOTEXTDECODER CIRCUIT ADJUSTMENT . .. .. .. . . . . . . . . . .. .. .. . . . . . . . . . 8
2-5. AUDIOCIRCUIT ADJUSTMENT . . . . . .. . . . . . . . . . . . . . . . . . .. . . .. .. . . . . . . . . . . . .. . . . . . 9
2-6. TUNER lFCIRCUIT ADJUSTMENT . .. . . . . . . . . . . . . . .. .. . . . . .. .. . . . . . . . . . .. .. .. .... 9
3. DISASSEMBLY PROCEDURES
3-1. REMOVAL OF REMOTE CONTROL UNITCASE . .. .. .. .. . . . . . . . . . . . . . . . .. .. ..l0
EP4,EP4Vseries
REFERENCE No. WM-531058
351lL1l(N)
I
1. CIRCUIT BOARD LOCATIONS
1-1. MAIN BOARDS
Video pre-amp unit
7
/
(
CP-1 (Video, Servo & Audio) board
W-lPowersupply)hard&~GMl
,:
,, ‘....
TM-2 (Operation) board
“ my*M~fld-eboad
TM-1 (Operation key & Display) board
Installed specific-equipment and models
TM-5 (OSA: on screen assist) board: except VHR-254G
TM-6 (Videotext decoder) board: VHR-254G only
TM-8 (VPS) board: VHR-240G, VHR-250G, VHR-254G
Appearance and specifications are subject to change without notice.
Figm 1-1
~ TM-8 (VPS) board
L13L073
1-2. LOCATION FOR TAPE PATH ADJUSTMENT
NOTE: Test point TP182 and TPI 83 for tape path adjustment is shown in figure below.
For adjustment, refer to the Mechanism Service Technical Information (WM-530599 and WM-531 029).
FOSL012
Shield case
F o m .I-@RqJq
s
r
TP183
TP182
CN181
SW-P.
ENV.
Fig. 1-2 Video pre-amp unit
—
—l—
3511J11(N)
2. ELECTRICAL ADJUSTMENT
L
2-1. PREPARATION
When
repairing the Video pre-amp unit
2-1-1. EQUIPMENT
(see Figs. 2-1-1 and 2-1 -4)
Colour TV monitor
PAL Colour-bar generator (with RF and LINE OUTPUT)
Audio signal generator
Oscilloscope (dual trace; frequency response: 10MHZ or
more; probe: 101 )
Frequency counter (countable to 10MHZ or higher)
Digital voltmeter
AC voltmeter
In/output probes
Alignment cassette (VHJ-0008) PAL Colour bar 1KHz
Alignment cassette (VHJ-0009) Monoscope 6KHz
Alignment cassette (VHJ-0023) PAL Monoscope 6KHz,
PAL Colour-bar 1KHz, SECAM Colour-bar 1KHz, PAL RF
Sweep MESECAM Colour-bar 1KHz, NTSC Colour-bar
1KHz.
Relay jig (vHJ-0066) 7-wire cable for Pre-amp unit
Relay jig (VHJ-0084) for CP-1 and CP-2 board
Relay jig (VHJ-0085) for Video pre-amp unit
2-1-2. CONNECTING THE RELAY JIG
When repairing CP-1
(see Figs. 2-1-2 and 2-1 -3)
NOTE: The connection of any Relay jigs can be done with-
1.
2.
3.
4.
5.
6.
out removing the front panel of the main unit.
Remove the seven red screws of the CP-1 board to take
out.
Insert the CP- 1 board in the slit of chassis as shown in
Fig. 2-1-3.
Connect CNO1 and CN02 of Relay jig (VHJ-0084) into
connectors of the PW-1 board and the Pre-amp unit, in the
direction of arrow as shown in Fig. 2-1-3. Fix the Relay jig
(VHJ-0084) with screw if necessary.
Connect 12-pin, 8-pin and 4-pin connectors of the Relay
jig to connectors CN541, CN101 and CN201 on the CP-1
board, respectively.
Connect connector from ACE head to CN06 of the Relay
jig (VHJ-0084).
After finishing the repairs and adjustments, put the Flat
cables (A) and (B) back to its former position.
CN08 connectorfrom
CN02 connectorto
connectorforACE
head
CN181 of Pre-amp unit.
\
1. Remove the Pre-amp unit from the chassis, connect
Relay jig (vHJ-0066) between the Pre-amp unit and
cylinder assembly.
2. Connect Relay jig (VHJ-00B4) excepting 8-pin connector
between the PW- 1 board and CP-1 board as shown in
Fig. 2-1-4. Fix the Relay jig (VHJ-0084) with screw if
necessary.
3. Connect Relay jig (VHJ-0085) between the top of Pre-
amp unit and CN101 on the CP-1 board.
NOTE: When repairing or adjusting the Pre-amp unit, be
sure to make contact an end of the Shield case
with Bracket of the Pre-amp unit to maintain the
shield effect. If the Pre-amp unit does not contact,
image can be obtained.
CAUTION: Be sure that the Relay jig does not have touch
with video head or the upper cylinder assem-
bly.
CN02 connector to
CN181 of Pre-amp unit
8-pin connector to
CN101 of CP-1 board
Relay jig VHJ-0085
Fig. 2-1-1
‘eaw’’’’’’’’a
CNO1 connector to
CN511 of PW-1 board
Relay jig VHJ-0084
b
4-pin connector to
CN201 of CP-1 board
Fig. 2-1-2
—2—
3511J21(N)
P1OJO17
Connector to CN06
1
r 12-pin
connector to CN541
v!!!
&’
*
‘~
1
“
w’
—
\
Relay jig (VHJ-O064)–
Screw
7
CNO1 toCN511 of PW-1 board
CN06 for connector from ACE head
4-pin connector to CN201
ACE head
Flat cable B (35-wires)
~
II I!_
-!
Fig. 2-1-3
WSJO18
ector
Vtdeo pre
nector
Relay jig
Syli
Fig. 2-1-4
2-1-3. SET-UP
Because the RF input signal is used for circuit adjustments,
connect the colour-bar generator to the ANT IN terminal of
the VCR. The RF input signal is processed by the tuner and
IFcircuit. It is improtant that the video output signal of the IF
circuit satisfies the items shown in Fig. 2-1-5. Connect the
oscilloscope to the VIDEO OUTPUT terminal of the video
circuit and terminate with a 75Q load, and then check the
video output signal.
.
.
.
The amplitude of the sync signal should be approxi-
mately 0.3 Vp-p.
The amplitude of the video signal should be approxi-
mately 0.7 Vp-p.
While observing the oscilloscope or TV screen, make
fine-tuning adjustments so that the colour burst
amplitude is approximately 0.3 Vp-p.
!--
Check to be sure that there is no spike noise in the sync
part of the horizontal sync signal.
W05JO01
100%
P
o.
-P
H syncsignal
Fig.
2-1-5
–3–
3513S11(N)
2-2. SERVO CIRCUIT ADJUSTMENT
o These adjustments should be carried out upon completion of the tape transport adjustments.
o If the tape transport adjustments (except the tilt adjustment) are carried out after these adjustments, follow the procedures
again in Item 1 SWITCHING POSITION ADJ.
“ When a cassette tape is loaded, auto-tracking will be set immediately after starting the first playback. As this will deviate the
tracking center set, be sure to press tracking buttons (+)or (-) once directly after starting playback to prevent auto-tracking from
being set. Press the tracking buttons (+) and (-) simultaneously, the tracking control to the center position.
“ Unless otherwise specified, all test point and adjustment location on the CP- 1 board.
io.
Item Input
Mode Point
Location Remark
W25SO01
%:?in’y+
VIDEO
OUTPUT
Alignment
TP101
Videosignal
cassette
J654321—
,
SWITCHING
V
sync
POSITION
(VHJ-0009
PLAY
RF SW VR351
pulse
1. Press the tracking buttons (+) and (-) simul-
VHJ&23)
TPI 83
taneously to the tracking center position (in-
(Video pre-
dictor panel displayed: “T —:— “).
amp unit)
2. Adjust VR351 so that the phase of the lead-
ing edge of the vertical sync signal isdelayed
6.5 &0.5 H from the rise of the RF switching
pulse waveform.
W20S011
E
Noiseat —
------ ------ ---
--.---- -------- -
Monitor
------- --------
upperside
screen
Noise at
-----.---- -----
------ ------- ---
lower side
----------- ----
1.
Set the VCR in the SP REC mode and record
at the middle of the cassette tape.
2. Playback the recorded part, and set the SP
STILL mode.
3. Press the tracking buttons (+) or (-) until V
SP mode
jitter (very fine movement of the vertical
REC
sync.) is minimized.
Colour bar
!
TRACKING
4. Set the SP SLOW mode by remote control unit.
buttons
5. Press the tracking buttons (+) and (-) simul-
SP SLOW
from
PIAY
2 TRACKING
Colour bar
\
TV screen and
taneously to adjust the tracking to the center
generator STILL
REC button
position (displayed: “T —:— “).
\
(Front panel)
Press the REC button during the tracking
SLOW
center display (approx. within three sec-
onds), at this time make sure that display as
shown “T- : —“.
6. Press tracking buttons(+) or (-) to send away
the noise which appears on the monitor
from the screen, and also adjust the position
of the noise at the upper side of the screen to
the similar position of the one at the lower
side judging from the center of the screen.
Press the REC button during the tracking
center display (approx. within three sec-
onds), at this time make sure that display as
shown ‘T— : —“.
—4—
-..”-..,., .
S51.XIZI(NI
]
10,
Item
Input
Mode
Point
Location
Remark
W20S011
E
Noise at — :.-::::.-::::::::-
Monitor
------ -------- .
upper side
screen
Noise at
------ ------- --
----- . . . . . ------
Iower
side
----- ------ ..-.
1.Set the VCR in the LP REC mode and record at
the middle of the cassette tape.
2. Playback the recorded part, and set the LP
STILL mode.
3. Pressthe tracking buttons(+) or (-) until V jitter
(very fine movement of the vertical sync.) is
LP mode
minimized.
REC
4. Set the LPSLOW mode by remote control unit.
Colour bar
I
TRACKING
5. Press the tracking buttons (+) and (-) simul-
LP SLOW
from PIAY
buttons
taneously to adjust the tracking to the center
3 TRACKING
Colour bar
TV screen
and
position (displayed: “T —:— “).
generator ST:LL
REC button
Press the REC button during the trakcing
(Front panel)
center display (approx. within three seconds),
SL~W
at this time make sure that display as shown
‘l–– : –“.
6, Press tracking buttons (+) or (-) to send away
the noise which appears on the monitor from
the screen, and also adjust the position of the
noise at the upper side of the screen to the
similar position of the one at the lower side
judging from the center of the screen.
Press the REC button during the tracking
center display (approx. within three seconds),
at this time make sure that display as shown
“T– : –“.
Note: Skew may occur at the upper side of the
playback monitor screen during the LP
mode, do not mistook this for noise.
PI2S051
1
TB-1
TP201 (HOT).
~--1
~--:; ICI 11
Terminal
TP202 (GND)@
::
II
r--; VR201
11
0
@ BIAS
TP101 ~~
IC301
VIDEOO
Q1012
OUT ‘‘
II
.-.
CN302
r-,
.----------------,
II
\-_-- _---- __--. -l
L.,’
II
~----------->
!
~ ------------------ .
,
L-_------ _-: .
Tuner ~ ~ ~
,-...
i:
I
L_-- _------ _—_----J
L--_j
Fig. 2-2-1 CP-I board (Foil sideview)
—5–
3513V11(N)
2-3. VIDEO CIRCUIT ADJUSTMENT
“
Use the Relay jig mentioned in the 2-1. PREPARATION to provide simple adjustment of the Video Pre-amp unit.
o Before these adjustments place the unit in the SP mode.
- Unless otherwise specified, alltest point and adjustment location on the CP-1 board.
Item
AGC
LEVEL
PB-Y
LEVEL
CARRIER
SET
DEVIATION
Input
Colour bar
100% white
level)
from
Colour bar
generator
Alignment
cassette
[VHJ-0008
VHJ:b23)
Colour bar
100% white
level) from
Colour bar
generator
1
No-signal
Colour bar
100% white
level)
from
Colour bar
generator
Mode
E-E
PLAY
REC
REC
(Adjust-
ment)
i
PIAY
(Check)
Point
TP102
VIDEO
OUTPUT
TP101
TPI 03
VIDEO
OUTPUT
TP101
Location
VR102
VR101
VR103
VR104
Remark
-100% white
w25v03(
J’54E!,*
u____._i
1. Terminate VIDEO OUTPUT terminal with a
75 ohms.
2. Adjust VRI 02 so that the level is 0.50*
0.025 Vp-p.
W25VC0
~1 00% white
* 0.05 v,-,
1. Terminate VIDEO OUTPUT terminal with a
75 ohms.
2. Adjust VR101 so that the level is 1.00 *
0.05 Vp-p.
1.
2.
3.
Input the PAL colour bar signal to VIDEO
INPUT terminal.
Set the channel selector buttons to the 8’AV’
position and put the VCR in the REC mode.
After removing the first colour bar signal
input from the video input terminal, imme-
diately adjust VR103 so that the frequency
becomes 3.83 * 0.05 MHz.
- 100% white
* 0.05 v,-,
1. Terminate VIDEO OUTPUT terminal with a
75 ohms.
2. Insert the blank tape to the VCR and record
colour bar signal.
3. Playback the recorded part, and check that
the level is 1.00* 0.05 Vp-p.
4. If the adjustment value is not satisfactory,
adjust VR104 and repeat step 3.
—6—
3511V21(N)
—
10
—
5
—
6
—
Item
C REC
CURRENT
Y REC
CURRENT
Input
Colour bar
from
Colour bar
generator
Colour bar
from
Colour bar
generator
Mode
REC
REC
Point
rP181 (HOT)
Shield case
(GND)
(Video pre-
amp unit)
rpl 81
(HOT)
Shield case
(GND)
(Video pre-
amp unit)
Location
VR181
(Video pre-
amp unit)
VR182
(Video pre-
amp unit)
Remark
WI 5VO06
t
150
* 5 mVp-p
i
1.
2.
Rotate VR182 so that the luminance level is
minimize.
Adjust VR181 so that the signal level is 150
* 5 mVp-p.
W25V028
T
480 + 20 mVp-p
A
II II
+t-
--it
H sync
H sync
1.
Connect the ground of the oscilloscope to
the Shield case of Video pre-amp.
2. Set the channel selector buttons to the AV
position.
3. Adjust VRI 82 so that the signal level at the
sync tip is 480 f 20 mVp-p.
Posvol2
Shield case
VR181
VR 182
4p 0? ‘Ekd+
TP181
CN181
I
Fig. 2-3-1 Video pre-amp unit
.-
.. .. .
—7—
3519X11(N)
2-4. VIDEOTEXT DECODER CIRCUIT ADJUSTMENT... For VHR-254G only
—.
“ Unless otherwise specified, all test point and adjustment location on the TM-6 board.
Uo. Item Input Mode
Point Location
Remark
1.Set the vartical scale (VOLTAGE/DIV.) of
the oscilloscope to 10 mV/DIV..
2. Connect the frequency counter to Emitter of
Emitter of
QIO12 and ground through a pre-amp of
1
DECODER
NONE E-E
QIO12
CT771
the above oscilloscope.
V)(O (CP-1 board)
3. Press the “MENU” button on the remote
Fig. 2-2-1
control unit.
4. After the frequency off by turning CT771 for
moment. Adjust CT771 so that the frequen-
cy is 4433619 * 50 Hz.
Ploxolo
J
Fig. 2-4-1 TM-6 board (Pam side view)
i-..:>.:
... ..... ,
>.... ...
,.~...<
—8–
3511A11(N)
2-5. AUDIO CIRCUIT ADJUSTMENT
“
Unless otherwise specified, all test point and adjustment location on the CP-1 board.
No.
Item
Input
1
BIAS
LEVEL
No-signal
Remark
1. Set the channel selector buttons to the AV
position and place in the SP record mode
without a signal.
2. Adjust VR201 so that the level is 23 mVrms.
3. Confirm that the bias frequency is 70 * 5
KHz.
Mode
REC
Point
TP201 (HOT)
TP202(GND)
Location
VR201
2-6. TUNER IF CIRCUIT ADJUSTMENT
“ There are two of the VIF unit’s type and different with the model as shown in figure below.
—
10
—
1
—
Item
Input
Mode
Point
Location Remark
1. Receive the middle electrical field (60 dB -
80 dB) of the TV channel, and slowly turn
VR611 from the point where snow-noise is
present to the point where it just disappears
from the monitor TV.
2. Confirm by monitor TV that there is no beat
and saturation (S/N is best point) when re-
ceiving any TV channel.
W
broadcast
VR611
(VIF unit)
RF AGC
E-E
TV screen
POSUO06
,.
VR611 &
RF AGC
B
:11
CP-1 board
w . . . . . . . . . .
CP-1board
~z..< .. .
..r.> ....r..—.z . . . .
TYPE B
TYPE A
Fig. 2-6-1 VIF unit (Parts side view)
I
,~.
—9–
3502B11(N)
3. DISASSEMBLY PROCEDURES
kiik.
-
fL,=
3-1. REMOVAL OF REMOTE CONTROL UNIT CASE
Open the remote control unit case as follows. Although a
large type remote control unit is shown in the figure bellow,
small type remote control unit can be openad by the same
procedures.
NOTE: When opening the remote control unit for repairing,
use a GUITER PICK made of plastic (1mm thickness) shown
in the Fig. 3-1-2 or the like (a thin plastic piece) to prevent
scratching.
Never use a metal screwdriverto avoid scratching.
1. Open the battery cover and take out batteries, the then
remove the bottom case fixing screw.
2. Applying force strongly to the battery compartment edge
in the arrow (A) direction by your thumb as shown in Fig.
3-1-1 to make a space (B) between the bottom and upper
case as shown in the cross section Fig. 3-1-3.
m7aool
Edge
r
\’
Make a space
[B)
/
$
Battery
compartment
Bottom case
7
‘%
Upper case
Fig. 3-1-1
FQ7aoos
a
GUITER PICK or
Thin plastic piece
Fig. 3-1-2
Make a space [B)
r#~
;;;ER
“>/,.
\\
Hooks (F)
Bonom case
Upper case
Fig. 3-1-3
To make this procedure easier, push the remote control
unit end (C) against your body Fig. 3-1-4.
3. Insert the GUITER PICK above mentioned into the space
(B) as shown in Figs. 3-1-3,3-1-4 and move the PICK in
the arrow (D) and (E)direction, then disconnect two hooks
(F) of the top of the cases.
4. Applying force to the space (B) and battery compartment
edge by your thumb so that the bottom case is separated
from the upper case as shown in the Fig. 3-1-5.
5. Insert the PICK into the space(G) of the case side slanting-
ly against the bottom case and move the PICK to
disconnect the hooks (H) of the side in order from top to
bottom Fig. 3-1-5.
6. Disconnect the hooks of the other side using the pick by
the same procedure as step 4.
F07BO02
ER PICK
c
Fig.
3-1-4
m7aoo4
Keep a space (B)
K
H)
Fig. 3-1-5
—lo—
,-
Apr.Z92/57m HA PrintedinJapan
SANYO Electric Co., Ltd.
Osaka, Japan
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