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10. RA-4/4A Deflection Circuit Troubleshooting
Chapter 10 - RA-4/4A Deflection Circuit Troubleshooting
A BOARD
1
10
11
12
8
9
7
6
5
3
2
4
8
9
FROM
IC516/7
HS BUFFER
+12V
+12V
C553
R545
C523
C543
C546
R550
C548
R537
C521
C522
R549
R536
R540
R548
R552
R562
C558
R577
HS
IN
VCC
HD
DUTY
H DRIVE
H OSC 1
H OSC 2
IC507
H JUNGLE
LA7856
FBP
IN
AFC
FILTER 2
FILTER 1
PHASE 1
PHASE 2
C550
R590
R591
R586
C571
Q514
N
R618
R532
R516
R541
R534
C525
C526
FROM IC512/24
AFC VDSP
TO D
BOARD
CN5004
CN509
FIGURE 10-1 - HORIZONTAL JUNGLE
10.1TVP14
5/24/02
Overview
With the introduction of scan line doubling, the RA-4 chassis introduced new circuit designs. The horizontal scan
rate operates at 31.5KHZ instead of the conventional 15.75KHZ. The YC/Jungle IC is replaced by a separate
video process (IC511) and a horizontal jungle (IC507). High voltage is developed in a separate circuit and will be
covered in Chapter 11. The vertical deflection circuit has had some notable changes, such as its own digital
deflection generator. The output stage remains relatively unchanged.
Horizontal Deflection
Figure 10-1 illustrates how horizontal scan is developed. IC507 is solely dedicated to this. Since the 480i signals
received by the set are up-converted, IC511 will provide H sync at 31.5KHZ to pin 1. Capacitors C521 and C522
will provide the necessary tuning for the oscillator to free run at the correct frequency. Pin 4 will receive the H
pulse for phase locking.