ELECTRICAL ADJUSTMENTS
D-1
2. BASIC ADJUSTMENTS
2-1: CONSTANT VOLTAGE
1.
2.
3.
4.
Place the set with Aging Test for more than 5 minutes.
Connect the digital voltmeter to TP501.
Set condition is AV MODE without signal.
Adjust the VR501 until the DC voltage is 117
±
0.5V.
1. ADJUSTMENT PROCEDURE
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).
1. Oscilloscope
2. Digital Voltmeter
3. Pattern Generator
Prepare the following measurement tools for electrical
adjustments.
1.
2.
3.
4.
5.
Place the set with Aging Test for more than 15 minutes.
Receive the VHF HIGH (63dB).
Connect the digital voltmeter to pin 5 of CP101.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (01) on the remote control to
select "RF AGC".
Press the VOL. +/- button on the remote control until the
digital voltmeter is 2.50
±
0.05V.
2-3: AGC VOLTAGE
2-4: CUT OFF
2-2: VCO
1.
2.
3.
4.
5.
6.
Place the set with Aging Test for more than 10 minutes.
Connect the oscillator (38.9MHz) to TP001.
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 VOL. +/- 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 Page UP button once to set to "VCO FINE"
mode.
Press the VOL. +/- 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" range 30~41, select 36.)
1.
2.
3.
4.
5.
Set condition is AV MODE without signal.
Using the remote control, set the brightness and
contrast to normal position.
Place the set with Aging Test for more than 15 minutes.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (00) on the remote control to
select "CUT OFF".
Adjust the Screen Volume until a dim raster is obtained.
2-5: WHITE BALANCE
NOTE: Adjust after performing CUT OFF adjustment.
1.
2.
3.
4.
5.
6.
7.
Place the set with Aging Test for more than 15 minutes.
Receive the gray scale pattern from the Pattern
Generator.
Using the remote control, set the brightness and
contrast to normal position.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (03) on the remote control to
select "R DRIVE".
Press the Page UP/DOWN button on the remote control
to select the "R DRIVE", "G DRIVE", "M R CUTOFF" or
"M G CUTOFF".
Adjust the VOL. +/- button on the remote control to
whiten the R DRIVE, G DRIVE, M R CUT OFF, and M G
CUT OFF at each step tone sections equally.
Perform the above adjustments 5 and 6 until the white
color is looked like a white.
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
2 seconds to appear the adjustment mode on the
screen as shown in Fig. 1-1.
2.
3.
Use the Channel button (0-9) or Channel UP/DOWN
button 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.
NO.
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
FUNCTION
CUT OFF
RF AGC
AGC GAIN
R DRIVE
R CUTOFF
G DRIVE
G CUTOFF
B DRIVE
H POSI (50)
V POSI (50)
V POSI (60)
V SIZE (50)
V SIZE (60)
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
TINT
SHARP
CONTRAST CENT
CONTRAST MAX
CONTRAST MIN
COLOR CENT
COLOR MAX
COLOR MIN
M R CUT OFF
M G CUT OFF
M B CUT OFF
CVBS OUT
APR THRESHOLD
BELL FILTER
BANDPASS
H POSI OSD
V POSI OSD
H POSI TEXT
V POSI TEXT
H POSI (60)
Fig. 1-2
Fig. 1-1
9- EXT
VCO Status -
MMM
35 H POSI OSD
36 V POSI OSD
37 H POSI TEXT
38 V POSI TEXT
39 H POSI 60
00 CUT OFF
117
57
117
57
45
