Memorex MT2206 Series A, Service Manual

Page: 12 / 64

ELECTRICAL ADJUSTMENTS
1.
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 (YG6260M) on the contract
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.)
2. BASIC ADJUSTMENTS BEFORE MAKING ELECTRICAL
ADJUSTMENTS
1. Oscilloscope
2. Digital Voltmeter
3. Multi-sound Generator
4. Pattern Generator
Prepare the following measurement tools for electrical
adjustments.
•
•
•
•
On-Screen Display Adjustment
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
1 second to appear the adjustment mode on the screen
as shown in Fig. 1-1. 1.
Fig. 1-1
Use the Channel UP/DOWN button or Channel button
(0-9) 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. 2.
3.
FUNCTION
OSD H
CUT OFF
H.VCO
H.PHAS
V.SIZE
V.SHIFT
R.DRIVE
B.DRIVE
R.BIAS
G.BIAS
B.BIAS
BRIGHT CENT
BRIGHT MAX
BRIGHT MIN
CONTRAST CENT NO.
00
01
04
05
06
07
08
09
10
11
12
13
14
15
16
Fig. 1-2
FUNCTION
CONTRAST MAX
CONTRAST MIN
COLOR CENT
COLOR MAX
COLOR MIN
TINT
SHARPNESS
FM LEVEL
LEVEL
SEPARATION 1
SEPARATION 2
TEST MONO
TEST STEREO
X-RAY TEST NO.
17
18
19
20
21
22
23
24
25
26
27
28
29
30
TV
00 OSD 16
2-1: CUT OFF
1.
2.
3.
4.
Adjust the unit to the following settings.
R.DRIVE=64, B.DRIVE=64, R.BIAS=64, G.BIAS=64,
B.BIAS=64, BRI CENT=110, CONT MAX=90.
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 (01) on the remote control to
select "CUT OFF".
Adjust the Screen Volume until a dim raster is obtained.
2-2: FOCUS
1.
2.
3. Receive the monoscope pattern.
Turn the Focus Volume fully counterclockwise once.
Adjust the Focus Volume until picture is distinct.
2-3: WHITE BALANCE
NOTE: Adjust after performing CUT OFF adjustment.
Place the set with Aging Test for more than 10 minutes.
Receive the white 100% signal from the Pattern
Generator.
Using the adjustment control, set the brightness and
contrast to normal position.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (10) on the remote control to
select "R. BIAS".
Press the CH. UP/DOWN button on the remote control to
select the "R. BIAS", "G. BIAS", "B. BIAS", R. DRIVE or
"B. DRIVE".
Adjust the VOL. UP/DOWN button on the remote control
to whiten the R. BIAS, G. BIAS, B. BIAS, R. DRIVE, and
B. DRIVE at each step tone sections equally.
Perform the above adjustments 6 and 7 until the white
color is looked like a white. 1.
2.
3.
4.
5.
6.
7.
2-4: SUB TINT/SUB COLOR
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Receive the color bar pattern. (RF Input)
Connect the oscilloscope to TP024.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (22) on the remote control to
select "TINT".
Press the VOL. UP/DOWN button on the remote control
until the section "A" becomes as straight line.
(Refer to Fig. 2-1)
Connect the oscilloscope to TP022.
Activate the adjustment mode display of Fig. 1-1 and
press the channel button (19) on the remote control to
select "COL.CENT".
Adjust the VOLTS RANGE VARIABLE knob of the
oscilloscope until the range between white 100% and
0% is set to 4 scales
Press the VOL. UP/DOWN button on the remote control
until the red color level is adjusted to 110% of the white
level. (Refer to Fig. 2-2)
Receive the color bar pattern. (Audio Video Input)
Press the TV/AV button on the remote control to set to
the AV mode. Then perform the above adjustments 2~8.
D-1