Chasis Service Adjustment Procedures; 130.0V B+ Voltage Confirmation; Source Voltage Chart; High Voltage Check - Panasonic CT-20D12DF Service Manual

Chasis service adjustment procedures

All service adjustments are factory preset and should not require adjustment unless controls and/or
associated components are replaced.
Note: Connect the (-) lead of the voltmeter to the appropriate ground. Use IC801's heat sink when the HOT
ground symbol ( ) is used. Otherwise, use COLD ground (
Figure 2. A-Board main
components
and test points
IC552
IC551
T
U
N
E
R
FA1 CLK
DATA FA2
COMPONENTS WITHIN DOT LINES ARE LOCATED AT THE OPOSITE SIDE OF BOARD.

130.0V B+ voltage confirmation

1. Set the BRIGHT and the PICTURE to minimum by
using the PICTURE menu.
2. Connect the DVM between C825 (+ side) and cold
ground ( ).
3. Confirm that B+ voltage is 130.0V ± 2.5V. This
voltage supplies B+ to the horizontal output &
flyback circuits.

Source voltage chart

120V AC line input. Set the BRIGHT and the PICTURE
to minimum by using the PICTURE menu. Use cold
ground ( ) for the (-) lead of the DVM.
LOCATION
TPD8
TPD9
IC002
A11
IC001
IC050
TPE10
TPE11
IC2302
COLD (
IC2301
VOLTAGE
26.0V ± 2V
25.0V ± 2V
) — tuner shield, IC451's heat sink or FA2.
IC003
C825 TPD14
TPD17
TPD15
TPD16
IC801
CRT
HOT ( )
GND
)
F801
LOCATION
IC552 Pin3
IC551 Pin3
D554 Cathode
Adjust PICTURE
adjustments.

High voltage check

1. Select an active TV channel and confirm that the
horizontal is in sync.
2. Adjust BRIGHTNESS and PICTURE using picture
icon menu, so video just disappears.
3. Confirm B+ 130V is within limit.
4. Using a high voltage meter confirm that the high
voltage is:
26.60kV±1.25kV
- 7 -
IC451
D561
TPD8
D554
TPD9
FOCUS SCREEN
VOLTAGE
5.0V ± 0.25V
9.0V ± 0.25V
200V ± 15V
menu for normalized video