ELECTRICAL ADJUSTMENTS
1. ADJUSTMENT PROCEDURE2. BASIC ADJUSTMENTS
Read and perform these adjustments when repairing the2-1: CONSTANT VOLTAGE
circuits or replacing electrical parts or PCB assemblies.
1.Place the set with Aging Test for more than 5 minutes.
CAUTION2.Connect the digital voltmeter to TP501.
3.Set condition is AV MODE without signal.
YUse an isolation transformer when performing any
4.Adjust the VR501 until the DC voltage is 115 ? 0.5V.
service on this chassis.
YBefore removing the anode cap, discharge electricity
2-2: VCO
because it contains high voltage.
YWhen removing a PCB or related component, after1.Place the set with Aging Test for more than 10 minutes.
unfastening or changing a wire, be sure to put the wire2.Connect the oscillator (38.9MHz) to TP001.
back in its original position.3.Activate the adjustment mode display of Fig. 1-1 and
YWhen you exchange IC and Transistor for a heat sink,press the channel button (13) on the remote control to
apply the silicon grease on the contact section of theselect "VCO COARSE".
heat sink. Before applying new silicon grease, remove all4.Press the VOL. +/- button on the remote control until
the old silicon grease. (Old grease may cause damagesthe "OK" appear on the screen. If the "OK" is not
to the IC and Transistor).displayed, select the "+" side on the changed from "+"
to "-".
Prepare the following measurement tools for electrical
5.Press the Page UP button once to set to "VCO FINE"
adjustments.
mode.
1. Oscilloscope6.Press the VOL. +/- button on the remote control to
2. Digital Voltmeterselect the 5 step down point from the upper limit on the
3. Pattern Generator"OK".
On-Screen Display Adjustment(Example: In case of the "OK" range 30~41, select 36.)
1. In the condition of NO indication on the screen.
2-3: AGC VOLTAGE
Press the VOL. DOWN button on the set and the
1.Place the set with Aging Test for more than 15 minutes.
Channel button (9) on the remote control for more than
2.Receive the VHF HIGH (63dB).
2 seconds to appear the adjustment mode on the
3.Connect the digital voltmeter to pin 5 of CP101.
screen as shown in Fig. 1-1.
4.Activate the adjustment mode display of Fig. 1-1 and
press the channel button (01) on the remote control to
select "RF AGC".
5.Press the VOL. +/- button on the remote control until the
digital voltmeter is 2.50 ? 0.05V.
2-4: CUT OFF
35 H POSI OSD1171.Set condition is AV MODE without signal.
36 V POSI OSD57
37 H POSI TEXT1172.Using the remote control, set the brightness and
38 V POSI TEXT57
39 H POSI 6045contrast to normal position.
00 CUT OFF
VCO Status -3.Place the set with Aging Test for more than 15 minutes.
9- EXTMMM
4.Activate the adjustment mode display of Fig. 1-1 and
Fig. 1-1
press the channel button (00) on the remote control to
select "CUT OFF".
2.Use the Channel button (0-9) or Channel UP/DOWN
5.Adjust the Screen Volume until a dim raster is obtained.
button on the remote control to select the options
shown in Fig. 1-2.
3.Press the MENU button on the remote control to end2-5: WHITE BALANCE
the adjustments.
NOTE: Adjust after performing CUT OFF adjustment.
NO. FUNCTIONNO. FUNCTION1.Place the set with Aging Test for more than 15 minutes.
00CUT OFF20TINT2.Receive the gray scale pattern from the Pattern
01RF AGC21SHARP
Generator.
02AGC GAIN22CONTRAST CENT
03R DRIVE23CONTRAST MAX3.Using the remote control, set the brightness and
04R CUTOFF24CONTRAST MINcontrast to normal position.
05G DRIVE25COLOR CENT
4.Activate the adjustment mode display of Fig. 1-1 and
06G CUTOFF26COLOR MAX
press the channel button (03) on the remote control to
07B DRIVE27COLOR MIN
08H POSI (50)28M R CUT OFFselect "R DRIVE".
09V POSI (50)29M G CUT OFF5.Press the Page UP/DOWN button on the remote control
10V POSI (60)30M B CUT OFF
to select the "R DRIVE", "G DRIVE", "M R CUTOFF" or
11V SIZE (50)31CVBS OUT
12V SIZE (60)32APR THRESHOLD"M G CUTOFF".
13VCO COARSE33BELL FILTER6.Adjust the VOL. +/- button on the remote control to
14VCO FINE34BANDPASS
whiten the R DRIVE, G DRIVE, M R CUT OFF, and M G
15VCO COARSE L135H POSI OSD
CUT OFF at each step tone sections equally.
16VCO FINE L136V POSI OSD
17BRIGHT CENT37H POSI TEXT7.Perform the above adjustments 5 and 6 until the white
18BRIGHT MAX38V POSI TEXTcolor is looked like a white.
19BRIGHT MIN39H POSI (60)Fig. 1-2
D-1 |
ACEC
