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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 IC803’s heat sink when the HOT ground
symbol ( ) is used. Otherwise, use COLD ground (
) — Tuner shield, IC451’s heat sink or FA2 (Fig. 5,Fig. 6).
Figure 5. A-Board Main Components and Test Points
MOMENTARILY CONNECT A JUMPER FOR ENTERING SERVICE MODE (FA1 to FA2 )
131.0V B+ Voltage Confirmation
1.
Set the Bright and the Picture to Minimum by
using the Picture Menu.
2.
Connect the DVM between C809(+ side) and hot
ground (
).
3.
Confirm that B+ voltage is 131.0V ± 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 the correct
ground for the (-) lead of the DVM.
C809(+) +131V
±
2.5V
TPD9
+13.0V ± 2V
C552(+)
+20.0V ± 2V (27&25”)
+8.0V ± 1V (32”)
TPD8
+27.4V ± 2V
CATHODE OF D554
+220.0V ± 15V (27”&32”)
+220.0V ± 5V (25”)
Adjust Picture Menu for normalized video adjustments.
B+ 5V Source Voltages
Volatile 5V:
C572, + side = IC552 pin 3, Tuner BPL, IC101 (IF 5V).
MPU 5V:
Emitter Q002 = IC001 (V
DD
, AV
DD
).
Standby 5V:
IC001 (key in 1), I
2
C EEPROM (IC002), Remote
Receiver.
B+ 9V Source Voltage
IC551 pin 3 = IC101 (IF 9V), Tuner (BM).
B+ 12V (Stand- by)
Note: +16V when power is on
Cathode D002= RL801 (on-off relay).
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+ 131V is within limit.
4.
Using a high voltage meter confirm that the High
Voltage is 29.25kV ± 1.25kV.
A-BOARD TEST LOCATIONS
T
U
N
E
R
IC 551
IC 101
1
52
26
27
IC 001
1
64
32
33
C552
C551
IC 002
D554
C809
IC 803
IC 451
TPD8
TPD9
FOCUS
SCREEN
F801
HOT ( )
COLD ( )
FA1
DATA TP15
CLK
FA2
IC 552
A11
SP
Q002
D002
RL801
TP16
C552
Note:
A/V Inputs only
available on
some models
