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: AGC VOLTAGE
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 15 minutes.
2 seconds to appear the adjustment mode on the2.Receive the UHF (63 ? 1dB).
screen as shown in Fig. 1-1.3.Connect the digital voltmeter to TP002.
4.Activate the adjustment mode display of Fig. 1-1 and
press the channel button (01) on the remote control to
select "RF AGC".TV
5.Press the VOL. +/- button on the remote control until the
digital voltmeter is 2.5 ? 0.05V.
2-4: CUT OFF
1.Set condition is AV MODE without signal.
35 H. POSI OSD 1282.Using the remote control, set the brightness and
contrast to normal position.
Fig. 1-1
3.Place the set with Aging Test for more than 15 minutes.
4.Activate the adjustment mode display of Fig. 1-1 and
2.Use the Channel button (0-9) or Channel UP/DOWN
button on the remote control to select the optionspress the channel button (00) on the remote control to
select "CUT OFF".
shown in Fig. 1-2.
3.Press the MENU button on the remote control to end5.Adjust the Screen Volume until a dim raster is obtained.
the adjustments.2-5: WHITE BALANCE
NO. FUNCTIONNO.FUNCTIONNOTE: Adjust after performing CUT OFF adjustment.
00CUT OFF20TINT
01RF AGC21SHARP1.Place the set with Aging Test for more than 10 minutes.
02AGC GAIN22CONTRAST CENT2.Receive the gray scale pattern from the Pattern
03R DRIVE23CONTRAST MAX
04R CUTOFF24CONTRAST MINGenerator.
05G DRIVE25COLOR CENT3.Using the remote control, set the brightness and
06G CUTOFF26COLOR MAXcontrast to normal position.
07B DRIVE27COLOR MIN4.Activate the adjustment mode display of Fig. 1-1 and
08H POSI (50)28M R CUT OFF
09V POSI (50)29M G CUT OFFpress the channel button (03) on the remote control to
10V POSI (60)30M B CUT OFFselect "R DRIVE".
11V SIZE (50)31CVBS OUT
12V SIZE (60)32APR THRESHOLD5.Press the Page UP/DOWN button on the remote control
to select the "R DRIVE", "G DRIVE", "M R CUTOFF" or
13VCO COARSE33BELL FILTER
14VCO FINE34BANDPASS"M G CUTOFF".
15VCO COARSE L135H POSI OSD6.Adjust the VOL. +/- button on the remote control to
16VCO FINE L136V POSI OSD
17BRIGHT CENT37H POSI TEXTwhiten the R DRIVE, G DRIVE, M R CUT OFF, and M G
18BRIGHT MAX38V POSI TEXTCUT OFF at each step tone sections equally.
19BRIGHT MIN39H POSI (60)Fig. 1-27.Perform the above adjustments 5 and 6 until the white
color is looked like a white.
D-1 |
ACEC
TOSHIBA
