Sanyo HT28745 Service Manual page 15

Drive Level Adjustment
13. Select "Drive Level Adjustment" Menu (between
NO. 08E and NO. 0B0) with L or M key. The Menu dis-
play will appear.
14. Adjust Red and Blue Drive Levels alternately with 1, 3,
7, or 9 key to produce normal black and white picture in
highlight areas. The Drive Level adjustment data will be
written in the Service Menu No. 106 and 108 automati-
cally. (See Figure 3.)
2 3
1
RD(–) (N/A) RD(+)
4 5 6
(N/A)
(N/A) (N/A)
7 8 9
BD(–) (N/A) BD(+)
Figure 3. Remote Control Number keys' functions in
Service Menu "Drive Level Adjustment"
15. Check for proper grayscale at all brightness levels.
Note: If Grayscale Adjustment is made after picture tube
replacement, check Brightness Adjustment.
BRIGHTNESS LEVEL ADJUSTMENT
Note: Grayscale Adjustment and High Voltage Check must be
completed before attempting Brightness Level
Adjustment.
1. Connect a color-bar generator to the analog antenna
terminal.
2. Switch the generator to the 15 IRE flat pattern.
3. Reset the picture controls to the Sports level. Full mode.
4. Connect voltmeter (high impedance) + lead to terminal
TP51 and – lead to terminal TP50 on P/D board. Set
voltmeter for 1.5V ~ 3V range.
5. Turn off the receiver and disconnect the AC power cord.
6. While pressing the VOLUME – key, reconnect the AC
power cord. The Service Menu display will now appear.
7. Select NO. 109 (SBR2: Sub Brightness, Bit 7 - 2) with L
or M key.
8. Adjust the data with numeric keys
9. Press the MENU key to turn off the Service Menu display.
10. Check brightness level on every active channel, readjust
(repeat steps 5 ~ 9), if necessary.
Note: Do not set to excessive brightness level, otherwise
the contrast level will be suppressed.
SUB CONTRAST ADJUSTMENT
1. Connect a color-bar generator to the analog antenna
terminal.
2. Switch the generator to the crosshatch pattern.
3. Connect oscilloscope probe (at least 50:1) to TP47G and
ground lead to TE47 on the CRT socket PWB.
4. Turn off the receiver and disconnect the AC power cord.
5. While pressing the VOLUME – key, reconnect the AC
power cord. The Service Menu display will now appear.
6. Select NO. 109 (SBR2: Sub Brightness, Bit 7 - 2) with L
or M key. Remember this data setting.
FOR RED DRIVE ADJUSTMENT
FOR BLUE DRIVE ADJUSTMENT
for 35
mVDC.
7. Set the data with numeric key to 2E with numeric keys.
8. Select NO. 10D (SCO4: Sub Contrast, Bit 7 - 4) with
L or M key.
9. Set the data with numeric keys 4 - 7 for 100Vp-p.
10. Reset brightness level to previous data (repeat steps
6 – 7). To turn off the Service Menu display, press the
MENU key.
SUB COLOR AND SUB HUE ADJUSTMENT
Sub Hue (Tint)
1. Connect a color-bar generator to the analog antenna
terminal. Set picture controls to Sports level.
2. Switch the generator to the color-bar (NTSC) pattern.
3. Connect oscilloscope probe (at least 50:1) to TP47G and
ground lead to TE47 on the CRT socket PWB.
4. Turn off the receiver and disconnect the AC power cord.
5. While pressing the VOLUME – key, reconnect the AC
power cord. The Service Menu display will now appear.
6. Select NO. 102 (SHU2: Sub HUE, Bit 7 - 2) with L or M key.
7. Set the data with numeric keys 2 - 7 for waveform
shown in Figure 5.
Sub Color
8. Select NO. 103 (SCL2: Sub Color, Bit 7 - 2) with L or M key.
9. Set the data with numeric keys 7 -2 for waveform
shown in Figure 6 (Flat Waveform).
10. After adjustment add 4 steps to NO. 102 (SHU2: Sub
HUE) data and 8 steps to NO. 103 (SCL2: Sub Color) data.
To turn off the Service Menu display, press the MENU
key.
— 15 —
100Vp-p
(From Blanking Level
to White 100IRE)
Figure 4. Sub Contrast
Figure 5. Sub Hue
Same level
Figure 6. Sub Color