SERVICE MANUAL
TOSHIBA
V726B/727B
MODEL
MC-Service
1
TOSHIBA V 726B
U-View Limited
Matrix
Item
See Model
Book
Deck Alignment ............................................................................ Toshiba V 856
6
Mech. Adjustments ...................................................................... Toshiba V 856
6
Deck Exploded View .................................................................... Toshiba V 856
6
General Information
Also Covers
V 727B
(V726B Only)
0001C
70061668
Owners Manual
English
0014C
70012604
Power Cord
0250
70051776
Front Panel
0350
70051141
Bottom Plate
0400
70051620
Top Cover
0450
70975305
Label
RS045
70041671
Res, Fusible
18
J 0.3W
RT809
70040122
Res, Carbon
1
J 0.3W
RW012
70041074
Res, Fusible
27
J 0.3W
RW021
70041672
Res, Fusible
5.6
J 0.3W
RW030
70041116
Res, Fusible
39
J 0.3W
LP002
70011949
Line Filter
LP020
70012427
Power Transformer TF-SMT13
CP001
70042150
Cap, Plastic
100nF M
CP003
70051665
Cap
2.2nF
400V
RP018
70041078
Res, Fusible
1.5
J 0.3W
RP021
70041673
Res, Fusible
2.2k
J 0.3W
RP071
70041073
Res, Fusible
22
J 0.3W
RP091
70042136
Res, Fuse
0.47
K
RP092
70040125
47
J 0.3W
BP 001
70011176
Inlet
FP001
70010445
Fuse, 1A, 250V
(V727B Only)
0001C
70061922
Owners Manual
English
0014C
70012731
Power Cord
0250
70052001
Front Panel
0350
70051141
Bottom Plate
0400
70051620
Top Cover
RS045
70041671
Res, Fusible
18
J 0.3W
RT809
70040122
Res, Carbon
1
J 0.3W
RW012
70041074
Res, Fusible
27
J 0.3W
RW021
70040122
Res, Carbon
1
J 0.3W
RW030
70041116
Res, Fusible
39
J 0.3W
LP002
70011949
Line Filter
LP020
70012427
Power Transformer TF-SMT13
CP001
70042150
Cap, Plastic
100nF M
CP003
70051665
Cap
2.2nF
400V
RP018
70041078
Res, Fusible
1.5
J 0.3W
RP021
70041673
Res, Fusible
2.2k
J 0.3W
Recommended Safety Parts
Item
Part No.
Description
Electrical Adjustments
<Test equipment required>
Adjustment will be performed with the following
test equipment.
1. Color TV (Monitor)
2. Oscilloscope, 2 CHs, 15 MHz or higher with
delay system
3. Frequency counter (7 digits or higher)
4. Millivoltmeter
5. Digital voltmenter
6. Tester(20k
/V)
7. Audio generator
8. Audio attenuator
9. Alignment tapes
Part code: ST-C6: 70909409, ST-C7:
70909410
10. Alignment screw driver (jig)
11. Color pattern generator
12. Video sweep generator
<Color bar signal>
Color bar signals of 75% recorded on the
alignment tapes are shown in Fig. 2-1-1.
Fig. 2-1-1
<Specified input and output levels, and
impedance>
Video input: Negative sync, standard composite
video signal 1 V(p-p), 75
Video output: Same as the video input 1 V(p-p),
75
Audio input: 308 mV(rms), more than 47 k
(phono type), more than 10 k
(21 pin type)
Audio output: 308 mV(rms), less than 4.7 k
(phono type), less than 1.0 k
(21 pin type)
<Alignment sequence>
Recorded the alignments in the sequence as
shown in Fig. 2-1-2.
Fig. 2-1-2
Alignment tape specifications
[1] ST-C6
[2] ST-C7
2-1. Servo Circuit
Main PC Board
Terminal PC Board
2-1-1. Playback Phase (PG) Adjustment
Test point:
Pins 1 and 2 of BW005, Pin 19 of BX102 (Video
out)
Test equipment: Oscilloscope
1. During playback press the VTR's channel up
and down buttons simultaneously to reset to
tracking center.
2. Confirm that phase difference between the
fall of the DFF pulse (pin 1 of BW005) and the
rise of CTL pulse (pin 2 of BW005) is 12
± 0.5
ins.
3. Further, observe the envelope (pin 4 of
BW005) waveform, and confirm that the ACE
head position adjustment and linearity
adjustment have been made, and C-SYNC
(pin 70 of IT001) is being input during
playback.
4. Set the VTR to the STOP mode.
5. Press the unit's channel up/down buttons
simultaneously for more than 5s.
6. Afterwards, within 2s, press the PLAY button
on the remote controller.
7. The automatic adjustment will be made for
about 10s, all the displays will blink. If the
automatic adjustment is not carried out,
confirm that the alignment tape has a safety
tab or not, and redo from the step 3.
1) When adjustment has been completed:
The display will blink for 10s, stop blinking
and return to the normal display in the STILL
mode, then it shifts to the playback display in
the playback mode.
2) When adjustment fails:
It goes into the STOP mode.
8. Confirm that the play indicator is displayed,
and confirm that the rising and falling edge of
the SW pulse is 6.5
± 0.5H from the V-sync
front edge of the video signal.
2-1-2. When lT004 is Replaced
When IT004 is replaced, the data in the VTR is
required to memorize in the new one. So
perform the following procedures.
1. Press the channel up/down buttons on the
VTR simultaneously for more than 5s while
the display blinks and the unit is in the power
off mode.
2. And then within 2s, press the CANCEL button
on the remote controller.
3. After displaying the address at the channel
display area and the data at the minute
display area, set the address to 12 using the
channel up/down buttons on the remote
controller. Next, set the data to d2 using the
FF/REW buttons on the remote controller.
The data goes up using FF button and down
using REW button.
4. Set each address and data in the table
following the description above.
Address Data
24
0A
25
03
26
15
27
0A
5. Perform the adjustment described in the item
"2-1-1. Playback Phase (PG) Adjustment".
6. Pull out the power cord plug from the AC
outlet once and insert the power cord plug
into the AC outlet again.
7. Perform the channel presetting as the IT004
replaced has no channel data.
2-2. Audio Circuit
Main PC Board
2-2-1. Bias Level Adjustment
Test point: Pins 1 and 2 of BS001
Test equipment: Millivoltmeter
Adjusting point: PS034
1. Set the VTR to record mode.
2. Connect pin 2 to the millivoltmeter and pin 1
to ground.
3. Adjust PS034 to obtain 3.6 (300
µA) ± 0.1 mV
(rms).
2-3. Self Diagnosis Function
2-3-1. Outline
When a tape running stops or the VTR enters
the power OFF mode, etc. due to some
abnormality, the abnormality is stored in the
EEPROM and displayed on the display tube.
2-3-2. Storing abnormal modes
· The abnormality is classed into 5 groups, and
the abnormality number, system control
mode, and the mechanism position at which
the abnormality occurred are stored in the
EEPROM.
· The writing timing is just after the abnormality
occurred.
2-3-3. Abnormality mode display
· Press the CH UP and CH DOWN buttons on
the VTR simultaneously for more than 5s.
· And then within 2s, press the STILL button on
the remote control.
· The system control mode at which the
abnormality occurred is displayed at the
channel display area, "E" is displayed at the
hour digit, abnormality generation number is
displayed at the minute digit, and the
mechanism position is displayed in the
second digit position.
· The abnormality mode is displayed regardless
of the power on off.
MC-Service
2
TOSHIBA V 726B
www.u-view.co.uk
Electrical Adjustments
Cont'd
· When the Counter Reset button is pressed in
the display period, the abnormality display
data is initialized and "-" is displayed.
The data displayed are as follows:
Abnormality generation number
Abnormal system control modes
Abnormal mechanism positions
Positions 0, 2, 4 exist as mechanism positions.
For example, 8 shows a position between 7 and
9 (between playback position and review
position).
2-3-4. Cylinder rotation time display
(1) Outline
All the time for which the cylinder is ON is
counted, memorized on EEPROM, and indi-
cated on the display tube.
(2) Display method
· Press the "CH UP" and "CH DOWN" button on
the main unit for more 5 sec. at the same
time.
· Next, within 2 sec. press the "STOP" button
on the remote control.
· The cumulative operation time of the cylinder
will be displayed for 30 sec. The time unit is
an hour.
(3) Example of display
· In case of 1234 hours.
· In case of 4 hours.
Electrical Adjustments
(V-727B Only)
1. ADJUSTMENT PROCEDURES
1-1. Servo Circuit
1-1-1. When IT004 is Replaced
When IT004 is replaced, the data in the VTR is
required to memorize in the new one. So
perform the following procedures.
1. Press the channel up/down buttons on the
VTR simultaneously for more than 5s while
the display blinks and the unit is in the power
off mode.
2. And then within 2s, press the CANCEL button
on the remote controller.
3. After displaying the address at the channel
display area and the data at the minute
display area, set the address to 12 using the
channel up/down buttons on the remote
controller. Next, set the data to d2 using the
FF/REW buttons on the remote controller. The
data goes up using FF button and down using
REW button.
Fig. 1-1
4. Set each address and data in the table
following the description above.
Table 1-1
Address
Data
24
0A
25
03
26
15
27
0A
28
5A
0C
7F
5. Perform the adjustment described in the item
"Playback Phase (PG) Adjustment".
6. Pull out the power cord plug from the AC
outlet once and insert the power cord plug
into the AC outlet again.
7. Perform the channel presetting as the IT004
replaced has no channel data.
Scart AV Switching Diagram
MC-Service
3
TOSHIBA V 726B
U-View Limited
Wiring Diagram
Wiring Diagram (V 727B)
MC-Service
MC-Service
4
TOSHIBA V 726B
www.u-view.co.uk
IF Tuner (V726B) Diagram
MC-Service