Electrical Adjustments; Basic Adjustments - Toshiba MD20FM1 Service Manual

1. BEFORE MAKING ELECTRICAL
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).
Prepare the following measurement tools for electrical
adjustments.
1. Oscilloscope
2. Digital Voltmeter
3. AC Voltmeter
4. Pattern Generator
5. Multi-Sound Signal Generator
On-Screen Display Adjustment
1. In the condition of NO indication on the screen.
Press the VOL. DOWN button on the set and the
Channel button (9) on the remote control for more than
1 second to appear the adjustment mode on the screen
as shown in Fig. 1-1.
Function
01 RCUT
Step No.
2. Use the Channel UP/DOWN button or Channel button
(1-0) on the remote control to select the options shown
in Fig. 1-2.
3. Press the MENU button on the remote control to end
the adjustments.

ELECTRICAL ADJUSTMENTS

3E
Fig. 1-1
NO. FUNCTION
01 R CUT OFF
02 G CUT OFF
03 B CUT OFF
04 G DRIVE
05 B DRIVE
06 BRIGHTNESS(CENT.)
07 BRIGHTNESS(MAX)
08 BRIGHTNESS(MIN)
09 COLOR(CENT.)
10 COLOR(MAX)
11 COLOR(MIN)
12 TINT
13 SUB CONTRAST
14 CONTRAST(CENT.)
15 CONTRAST(MAX)
16 CONTRAST(MIN)
17 SHARPNESS
18 RGB CONTRAST
19 H POSITION
20 V POSITION
21 V SIZE
22 V LINEARITY
23 V S CORRECTION
24 EW PARABOLA CORR.
25 EW TRAPEZIUM CORR.
26 H SIZE
27 V EHT
28 H EHT
29 RF AGC
30 V CENTERING
31 CORNER CORR. TOP
32 CORNER CORR. BTM
33 OSD H
34 FM LEVEL
35 TEST PWM
36 TEST TONE CONTROL

2. BASIC ADJUSTMENTS

2-1: CONSTANT VOLTAGE
1. Set condition is AV MODE without signal.
2. Using the remote control, set the brightness and contrast
to normal position.
3. Connect the digital voltmeter to TP401.
Adjust the VR502 until the digital voltmeter is 111 ± 0.5V.
4.
2-2: RF AGC
1. Receive the VHF HIGH (63dB).
2. Place the set with Aging Test for more than 15 minutes.
3. Connect the digital voltmeter between the pin 5 of
CP101 and the pin 1 of CP101.
4. Activate the adjustment mode display of Fig. 1-1 and
press the channel button (29) on the remote control to
select "AGC".
5. Press the RIGHT/LEFT button on the remote control
until the digital voltmeter is 2.7 ± 0.05V.
2-3: FOCUS
1. Receive the monoscope pattern.
2. Turn the Focus Volume fully counterclockwise once.
3. Adjust the Focus Volume until picture is distinct.
2-4: CUT OFF
1. Adjust the unit to the following settings.
R CUT=7F, G CUT=7F, B CUT=7F, G DRV=3F,
B DRV=3F
2. Place the set with Aging Test for more than 15 minutes.
3. Set condition is AV MODE without signal.
4. Using the remote control, set the brightness and contrast
to normal position.
5. Activate the adjustment mode display of Fig. 1-1 and
press the channel button (72) on the remote control to
select "CUT OFF".
6. Adjust the Screen Volume until a dim raster is obtained.
D-1
NO FUNCTION
.
37 BRI. AV(CENT.)
38 BRI. AV(MAX)
39 BRI. AV(MIN)
40 COL. AV(CENT.)
41 COL. AV(MAX)
42 COL. AV(MIN)
43 TINT AV
44 SUB CONTRAST AV
45 CONT. AV(CENT.)
46 CONT. AV(MAX)
47 CONT. AV(MIN)
48 SHARPNESS AV
49 BRI. DVD(CENT.)
50 BRI. DVD(MAX)
51 BRI. DVD(MIN)
52 COL. DVD(CENT.)
53 COL. DVD(MAX)
54 COL. DVD(MIN)
55 TINT DVD
56 SUB CONTRAST DVD
57 CONT. DVD(CENT.)
58 CONT. DVD(MAX)
59 CONT. DVD(MIN)
60 SHARPNESS DVD
61 BRI. GAME(CENT.)
62 BRI. GAME(MAX)
63 BRI. GAME(MIN)
64 CONT. GAME(CENT.)
65 CONT. GAME(MAX)
66 CONT. GAME(MIN)
67 TUNING V MUTE
68 POWER ON V MUTE
69 INPUT LEVEL
70 SEPARATION L
71 SEPARATION H
72 CUT OFF
Fig. 1-2