Toshiba VTW21FQR, Service Manual

Page: 57 / 116

ELECTRICAL ADJUSTMENTS
D3-1
2. BASIC ADJUSTMENTS
(VCR SECTION)
2-1: PG SHIFTER
1.
2.
3.
Playback the alignment tape.
Press and hold the Tracking-Auto button on the remote
control more than 2 seconds to set tracking to center.
Press the VOL. DOWN button on the set and the
channel button (3) on the remote control simultaneously
until the indicator REC disappears. If the indicator REC
disappears, adjustment is completed.
(If the above adjustments doesn't work well:)
4.
5.
6.
7.
Connect CH-1 on the oscilloscope to TP4502 and CH-2
to TP4501.
Press the VOL. DOWN button on the set and the
channel button (3) on the remote control simultaneously
until the indicator REC disappears.
When the REC indicator is blinking, press both VOL.
DOWN button on the set and the channel button (4) on
the remote control simultaneously and adjust the
Tr/- button until the arising to the down of Head
Switching Pulse becomes 6.5
±
0.5H.
(Refer to Fig. 2-1-A, B)
Stop the alignment tape.
CH-1
CH-2
6.5H
Fig. 2-1-A
CH-2
CH-1
6.5H
Fig. 2-1-B
2-2: VCO
1.
2.
3.
4.
5.
6.
Place the set in Aging Test for more than 10 minutes.
Connect the oscillator (38.5MHz) to TP601.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (13) on the remote control to
select "VCO COARSE".
Press the LEFT/RIGHT button on the remote control
until the "OK" appear on the screen. If the "OK" is not
displayed, select the "-" side on the changed from "+" to
"-".
Press the channel button (14) to set to "VCO FINE"
mode.
Press the LEFT/RIGHT button on the remote control to
select the 5 step down point from the upper limit on the
"OK".
(Example: In case of the "OK" point 41, select 36.)
NO.
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38 FUNCTION
CUT OFF
RF AGC
AGC GAIN
R DRIVE
R CUTOFF
G DRIVE
G CUTOFF
B DRIVE
H POSI 50Hz /60Hz
V POSI 50Hz /60Hz
---
V SIZE 50Hz /60Hz
---
VCO COARSE
VCO FINE
VCO COARSE L1
VCO FINE L1
BRIGHT CENT
BRIGHT MAX
BRIGHT MIN NO.
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19 FUNCTION
CONTRAST CENT
CONTRAST MAX
CONTRAST MIN
COLOR CENT
COLOR MAX
COLOR MIN
TINT
SHARP
M R CUT OFF
M G CUT OFF
M B CUT OFF
H POS OSD
---
---
---
CVBS OUT
APR THRESHOLD
BELL FILTER
BANDPASS
Fig. 1-2
(MONITOR TUNER)
1. ADJUSTMENT PROCEDURE
On-Screen Display Adjustment
1.
2.
Unplug the AC plug for more than 30 minutes to set the
clock to the non-setting state. (To release the Back-Up
immediately, take the short circuit between C1003 and
GND at the Power Off.) Then, set the volume level to
minimum.
Press the VOL. DOWN button on the set and the
channel button (9) on the remote control for more than
2 seconds to display adjustment mode on the screen as
shown in Fig. 1-1.
Fig. 1-1
01 RF AGC 30
TV
3.
4.
Use the Channel UP/DOWN button or Channel button
(0-9) on the remote control to select the options shown
in Fig. 1-2.
Press the MENU button on the remote control to end
the adjustments.
Read and perform these adjustments when repairing the
circuits or replacing electrical parts or PCB assemblies.
CAUTION
•
•
•
•
Use an isolation transformer when performing any
service on this chassis.
Before removing the anode cap, discharge electricity
because it contains high voltage.
When removing a PCB or related component, after
unfastening or changing a wire, be sure to put the wire
back in its original position.
When you exchange IC and Transistor for a heat sink,
apply the silicon grease on the contact section of the
heat sink. Before applying new silicon grease, remove all
the old silicon grease. (Old grease may cause damages
to the IC and Transistor.)
Oscilloscope
Digital Voltmeter
Pattern Generator 1.
2.
3.
Prepare the following measurement tools for electrical
adjustments.