Table of Contents
Advertisement
EN 144
9.
= [4.5m * 22K +2 * 0.7] + 1.87 * 22K / 820 * (Vpin4 - Vpin2)
With the above equation, we know that we have a signal
amplification AC gain of 1.87 * 22K * 820 ~ 50
For the fixed DC gain, it is referring to the 172V adjustment, i.e.,
POT meter adjustment input to pin 2 and determine Cathode
DC level, which fix black level at 172V when HOP IC black level
is 2.5V.
Therefore, if HOP IC output 2.5Vdc level, we can obtain 172V
black level at Cathode by adjusting POT meter. With that, RGB
amplifier will amplify and display the signal level from HOP IC
with level >2.5V. All the signal < 2.5V will be below 172V at
Cathode and blanked not to display.
Misc. components:
•
3208/7202/3223/3209/3204: Buffer of RGB. Temperature
compensation for PNP buffer at MSB board.
•
3225/3227/3226: POT meter adjustment for 172V.
•
2215/2212/3214/2204/2207: Noise decoupling of non-
inverting input pin.
•
3228/3216/2216/2213: +12V decoupling.
•
3224/3213: Gain components.
•
3215/2210: Gain for high frequency.
•
2214/2217/2224: +200V decoupling.
•
2203/6202/3220: AKB feedback voltage filtering and
clamping. AKB is not used in HDPTV2K6 and so
•
3220 is not inserted. The AKB path is disconnected to
MSB.
•
3206/5202/5203/3211/3218/6201: Cathode waveform
smoothing and flash preventing.
•
3210/2206: G2 voltage decoupling and flash preventing.
•
3202/6200/2218: G1 voltage decoupling and flash
preventing.
•
2200/2201/5200/5201: Filament voltage decoupling.
9.5
MSB HOP Section
B
L
1
3
3
2
8
Y
R
S
A
T
U
R
A
I T
O
N
Y
N I
C
O
N
T
R
O
L
2
7
U
G
C
O
N
T
R
A
S
U
N I
S
W
T I
C
H
C
O
L
O
U
R
C
O
N
T
R
O
2
6
V
B
D
F I
F
E
R
E
N
C
E
V
N I
M
A
T
R
X I
S
A
T
C
O
N
T
R
Y
U
V
3
0
R
1 I
3
1
R
G
B
Y -
U
V
B
L
A
C
K
G
1 I
M
A
T
R
X I
S
T
R
E
T
C
H
3
2
B
1 I
V 2
P
3
9
V 1
P
1
7
D
E
C
V
D
7
D
E
C
1
8
B
G
S
O
F
T
S
U
P
P
L
Y
S
T
A
R
T
S /
T
O
G
N
D
1
6
L
O
W
P -
O
W
E
G
N
D
2
1
9
S
T
A
R
- T
U
P
H
S -
H
F I
T
2
3
V D
2
4
H D
C
L
O
C
K
G
E
N
E
R
A
I T
O
N
P
H
A
S
E
2 -
H
O
R
Z I
O
N
T
A
N
D
L
O
O
P
O
U
T
P
U
T
1
2
H
S
E
L
1
t s
L
O
O
P
2
0
2
1
9
1
3
1
4
5
H
F
B
X
T
A
I L
X
T
A
L
O
S
C
O
F
L
A
S
H
H
O
D
P
C
Figure 9-3 MSB HOP IC
The HOP is functioning as a horizontal output processor, which
takes care of horizontal and vertical deflection drive, EW drive,
and RGB drive.
9.5.1
Horizontal deflection drive
For the horizontal deflection drive, HOP pin8 output Hout to
horizontal base driver through connector 1620 pin9. The
switching Hout then drives the horizontal output stage with the
yoke. The yoke coil is being switched, and horizontal yoke
current is induced to achieve horizontal scanning.
Related to horizontal scanning, we have Hfb feedback from
horizontal deflection stage. Hfb is for phase II locking, which
EBJ1.0U
Circuit Descriptions, Abbreviation List, and IC Data Sheets
R
2 I
G
2 I
B
2 I
B
L
2
F
B
C
S
O
P
W
L
3
5
3
6
3
7
3
8
2
9
3
4
R
R
R
O
U
T
P
U
T
W
H
T I
E
P
O
N I
T
A
M
P
L
F I
E I
R
G
G
A
N
D
G
T
R
G
B
A
N
D
L
N I
S
E
R
I T
O
N
B
I R
G
H
T
N
E
S
S
B
B
B
B
U
F
F
E
R
C
O
N
T
R
O
L
B
L
U
E
S
T
R
E
T
C
H
w
i h
e t
B
I R
p
i o
t n
P
W
L
A
N
D
C
O
N
T
N I
U
O
U
S
B
E
A
M
C
A
T
H
O
D
E
T
D
A
9
3
3
x
H
C
U
R
R
E
N
T
C
A
L
B I
R
A
I T
O
N
I L
M
T I
E
R
1 ×
2
P
9
6
B -
T I
D
A
C
s
I
C
B -
U
S
H
V /
D
V I
D I
E
R
2 ×
R
4
B -
T I
D
A
C
s
T
R
A
N
S
C
E
V I
E
R
G
E
O
M
E
T
R
Y
C
O
N
T
R
O
L
A
L
R
A
M
P
V
E
R
T
C I
A
L
- E
W
G
E
N
E
R
A
T
O
R
G
E
O
M
E
T
R
Y
G
E
O
M
E
T
R
Y
8
2
2
1
5
1
6
1
2
4
3
V
S
C
I
r
f e
U
T
L
P
S
U
V
D
O
A
V
D
O
B
E
H
T
N I
E
W
O
locks the horizontal output stage flyback phase to HOP Hfreq
local oscillator. The HOP IC will shut down if Hfb is not
available.
9.5.2
Vertical Deflection Drive
For the vertical deflection drive, HOP pin1 and pin2 output
differential vertical current source VDOA and VDOB to vertical
IC STV8172A through connector 1620 pin3 and pin4. The
sawtooth differential current source VDOA and VDOB is then
being amplified by STV8172A and a sawtooth vertical yoke
current is induced to achieve vertical scanning.
Related to the vertical scanning, we have the sawtooth
generator pin16 IREF and pin15 VSC. IREF is a constant
current fixed by resistor 3616. This IREF then charges 2615 to
obtain a sawtooth current. During every vertical flyback period,
2615 is being switched to gnd and recharged again during the
scanning period. A periodic sawtooth is then achieved and
delivered to the vertical deflection stage through VDOA and
VDOB.
9.5.3
East West (EW) Drive
For the EW drive, HOP pin3 output EW current source EWO to
EW correction circuit 7802/7803 through connector 1620 pin5.
The parabola EW current source is input to 7803 pin3 and pin5
and compared with sawtooth on pin2 and pin6. The current
source will sink current from the EW correction through
switching method (class D). This I_ew * (R3829//R3823) will
determine the voltage of the diode modulator 6810 pin 2
voltage. This will then modulate the horizontal deflection
current to achieve EW size control.
9.5.4
RGB Drive
For the RGB drive, HOP pin30/31/32/23/24 receive RGBHV
from EBJ panel. HOP IC will then convert and amplify these
standard 1080i RGBHV to CRT RGB drive signals pin40/41/42.
RGB drive output from HOP is with ~6V max. There are PNP
4
0
buffers 7702/12/20 connected between RGB output and CRT
R
O
4
1
G
O
4
2
board.
B
O
For the Blue channel, due to the blue CRT non-linear phosphor
4
4
B
L
K
N I
characteristic, a blue stretch circuit is designed in between
4
3
BLUE output and the PNP buffer. The Blue stretch circuit
B
C
L
2
5
D
A
C
O
U
T
consists of 7721/22/23. Depending on 7722 voltage level, 7723
1
0
S
C
L
may be turned "on" and so the gain of the circuit changes and
1
1
S
D
A
obtains a two-section non-linear gain to compensate the blue
phosphor characteristic.
HV sync. is embedded into RGB output which function to blank
and synchronize the RGB display.
Related to RGB, we have a Beam Current Limiter (BCL or ABL)
G_15860_052.eps
070406
connected to LSP through 1620 pin1. The BCL circuit is to limit
the beam when the display exceeds a certain driving level. This
will prevent the display from blooming due to too high contrast.
The circuit also set a max beam current, which is 1.8mA for the
application. The max. beam is set by LSP 3910/3911.
When1620 pin1 voltage goes lower till certain level said 2.8V,
HOP Contrast/Brightness gain controller will start to react and
reduced the gain and so limit the drive going too high.
Making use of the BCL function, 7660 is designed in to prevent
the blue gun from damaging, which may happen if we have a
blue background display for a long time. 7660 compares the
driving level of the Red/Green combination and the Blue level.
When the Blue level becomes higher than the Red/Green
combination, 7660 starts to turn "on" and limit the RGB drive
including the Blue drive.
Advertisement
Table of Contents
