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 15 minutes.
CAUTION2.Connect the digital voltmeter to TP502.
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
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 TP003.
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: 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 seconds to appear the adjustment mode on the2.Connect the oscillator (33.95MHz) to TP003.
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
L1" mode.
35 H POSI OSD1206.Press the VOL. +/- button on the remote control to select
36 V POSI OSD57
37 H POSI TEXT119the 5 step down point from the upper limit on the "OK".
38 V POSI TEXT57
39 H POSI 6034(Example: In case of the "OK" point 30~41, select 36.)
00 CUT OFF
VCO Status -
9- EXTMMM2-4: AGC VOLTAGE
Fig. 1-1
1.Place the set with Aging Test for more than 15 minutes.
2.Receive the UHF (63 ? 1dB).
2.Use the Channel button (0-9) or Channel UP/DOWN
3.Connect the digital voltmeter to TP002.
button on the remote control to select the options4.Activate the adjustment mode display of Fig. 1-1 and
shown in Fig. 1-2.
press the channel button (01) on the remote control to
3.Press the MENU button on the remote control to endselect "RF AGC".
the adjustments.
5.Press the VOL. +/- button on the remote control until the
digital voltmeter is 2.5 ? 0.05V.
NO. FUNCTIONNO.FUNCTION
00CUT OFF20TINT
01RF AGC21SHARP2-5: CUT OFF
02AGC GAIN22CONTRAST CENT
03R DRIVE23CONTRAST MAX1.Set condition is AV MODE without signal.
04R CUTOFF24CONTRAST MIN2.Using the remote control, set the brightness and
05G DRIVE25COLOR CENTcontrast to normal position.
06G CUTOFF26COLOR MAX
3.Place the set with Aging Test for more than 15 minutes.
07B DRIVE27COLOR MIN
08H POSI (50)28M R CUT OFF4.Activate the adjustment mode display of Fig. 1-1 and
09V POSI (50)29M G CUT OFFpress the channel button (00) on the remote control to
10V POSI (60)30M B CUT OFF
select "CUT OFF".
11V SIZE (50)31CVBS OUT
12V SIZE (60)32APR THRESHOLD5.Adjust the Screen Volume until a dim raster is obtained.
13VCO COARSE33BELL FILTER
14VCO FINE34BANDPASS
15VCO COARSE L135H POSI OSD
16VCO FINE L136V POSI OSD
17BRIGHT CENT37H POSI TEXT
18BRIGHT MAX38V POSI TEXT
19BRIGHT MIN39H POSI (60)Fig. 1-2
D-1 |
ACEC
