6
No. 51758
AV-28BK5ECB
AV-28BK5ECS
IC7202
Video Memory
IC7203
Video Memory
IC7204
PLL
<READ>
IC7201
DOUBLE SCAN CONVERTER
<TC90A36F>
IC7205
PLL
<WRITE>
LPF
Q7301-Q7304
LPF
Q7311-Q7314
LPF
Q7321-Q7324
LPF
Q7371-Q7374
LPF
Q7361-Q7364
LPF
Q7351-Q7354
IC7341
Inverter
VD
HD
2VD
2HD
Y
U
V
2V
2U
2Y
12
85
90
92
100
98
6
10
5
1
4
6
11
13
31
|
50
9
|
31
71
70
68
63
59
53
9
4
5
4
Digital scan circuit
100Hz Digital Scan Converter circuit
100Hz converter circuit consists of the following ICs.
- TC90A36F, IC7201
Field Progressive Converter
- MSM518221A, IC7202, IC7203
Video Memory
- TLC2932I, IC7204, IC7205
PLL (Phase Locked Loop)
- MC74HC04AFP, IC7341
invertor
The Y-signal output from IC101 is sent to pin 85 of IC7201<TC90A36F>, field progressive
converter, after controlling the amplitude level and band-pass limiting by the circuit consist of
Q7301, Q7302, Q7303, Q7304 and 8MHz LPF. The U/V-signal are also controlling the amplitude
level and band-pass limiting by the circuit consist of Q7311, Q7312, Q7313, Q7314, Q7321,
Q7322, Q7323, Q7324 and 4MHz LPF respectively. The U-signal is sent to pin 90 of IC7201and
the V-signal is sent to pin 92 of IC7201. The HD signal is sent to pin 63 of IC7201 with positive
polarity through IC7341 for shaping the waveform. The VD-signal is sent to pin68 of IC7201 with
negative polarity through IC7341.
The Y-signal input to IC7201 is converted from A to D in 8bit and output from pins 31 to 50 of
IC7201 to pins 1 to 4 and 24 to 27 of IC7203<MSM51822A>, video memory, for writing.
[Digital Scan Operation]
Fig.-6
CHASSIS DESCRIPTION