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Chassis 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 10. A-Board main
components
(varies depending on model
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
23.0V ± 2.0V
TPD9
13.0V ± 2.0V
IC552 Pin3
5.0V ± 0.25V
IC551 Pin3
9.0V ± 0.25V
D554 Cathode
180V ± 15V
IC002
A11
IC001
IC050
TPE10
TPE11
IC2302
IC2301
VOLTAGE
13"
20" & 27"
26.0V ± 2.0V
13.0V ± 2.0V
5.0V ± 0.25V
9.0V ± 0.25V
200V ± 15V
) — tuner shield, IC451's heat sink or FA2.
IC003
C825
TPD17
TPD15
TPD16
IC801
CRT
HOT (
)
GND
COLD (
)
F801
Adjust picture menu for normalized video adjustments.
High voltage check
1. Select an active TV channel and confirm that
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:
23.75kV ± 1.25kV
27.70kV ± 1.25kV
29.25kV ± 1.25kV
- 15 -
TPD14
IC451
D561
TPD8
TPD9
FOCUS
SCREEN
13"
20"
27"
D554
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