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 135 ? 0.5V.
service on this chassis.
YBefore removing the anode cap, discharge electricity
2-2: VCO COASE, VCO FINE
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" point 30~41, select 36.)
1. In the condition of NO indication on the screen.
2-3: VCO COASE L1, VCO FINE L1
Press the VOL. DOWN button on the set and the
Channel button (9) on the remote control for more than1.Place the set with Aging Test for more than 10 minutes.
2.Connect the oscillator (33.95MHz) to TP001.
2 seconds to appear the adjustment mode on the
screen as shown in Fig. 1-1.3.Activate the adjustment mode display of Fig. 1-1 and
press the channel button (15) on the remote control to
select "VCO COARSE L1".
4.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 "+".
5.Press the Page UP button once to set to "VCO FINE
35 H POSI OSD135L1" mode.
36 V POSI OSD576.Press the VOL. +/- button on the remote control to
37 H POSI TEXT130
38 V POSI TEXT57select the 5 step down point from the upper limit on the
39 H POSI 6044
00 CUT OFF"OK".
VCO Status -
9- EXTMMM(Example: In case of the "OK" point 30~41, select 36.)
Fig. 1-12-4: AGC VOLTAGE
1.Place the set with Aging Test for more than 15 minutes.
2.Use the Channel button (0-9) on the remote control to
2.Receive the UHF (63 ? 1dB).
select the options shown in Fig. 1-2.
3.Connect the digital voltmeter to pin 5 of CP101.
3.Press the MENU button on the remote control to end
4.Activate the adjustment mode display of Fig. 1-1 and
the adjustments.
press the channel button (01) on the remote control to
NO. FUNCTIONNO.FUNCTIONselect "RF AGC".
00CUT OFF20TINT5.Press the VOL. +/- button on the remote control until the
01RF AGC21SHARPdigital voltmeter is 2.50 ? 0.05V.
02AGC GAIN22CONTRAST CENT
03R DRIVE23CONTRAST MAX
04R CUTOFF24CONTRAST MIN2-5: CUT OFF
05G DRIVE25COLOR CENT
06G CUTOFF26COLOR MAX1.Set condition is AV MODE without signal.
07B DRIVE27COLOR MIN2.Using the remote control, set the brightness and
08H POSI (50)28M R CUT OFFcontrast to normal position.
09V POSI (50)29M G CUT OFF
3.Place the set with Aging Test for more than 15 minutes.
10V POSI (60)30M B CUT OFF
11V SIZE (50)31CVBS OUT4.Activate the adjustment mode display of Fig. 1-1 and
12V SIZE (60)32APR THRESHOLDpress the channel button (00) on the remote control to
13VCO COARSE33BELL FILTER
select "CUT OFF".
14VCO FINE34BANDPASS
15VCO COARSE L135H POSI OSD5.Adjust the Screen Volume until a dim raster is obtained.
16VCO FINE L136V POSI OSD
17BRIGHT CENT37H POSI TEXT
18BRIGHT MAX38V POSI TEXT
19BRIGHT MIN39H POSI (60)Fig. 1-2
D-1 |
ACEC
