External Recorder Playback Circuit; Colour Encoder - Sharp MZ-700 Service Manual

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5-2. External recorder playback circuit
When the external recorder is used, connection is made
with the 8255 by shorting P-12. In this condition, the
write data (8255 PC output)
is
differentiated and sent
to the recorder. In the case of read, the signal peak is
chopped by DI and D2 (about O.6V), amplified in the
1.2V limiter (about 1.2V), then amplified to 5V in the
next stage amplifier. The phase of the read signal may
be inverted with the tape switch after this is to compensate
for phase difference owing to the head of the recorder.
When proper operation is not attained with an external
recorder, adjust the volume control and the tone control
knobs to optimum positions. Those which incorporate
treble and base for tone control should preferably be set to
a flat condition, and those with only a tone control knob,
should be set to a high condition.
6. COLOUR ENCODER
6-1.
Colour encoder
• The encoder unit should be replaced as a unit part.
• Input signals
• COLOR
• CSYNC
• HSYNC
• VSYNC
• R
• G
• B
Colour sub-carrier wave frequency
Composite synchronizing signal
Horizontal synchronizing signal
Vertical synchronizing signal
• CVIDEO
'X. Rear view
,~
B/W-Colour
sw
I
+
+
6+
?
I
RF CH1- VIDEO 8pin
OUT CH2 OUT Din
SW
19
• 8-Pin DIN connector
I VIDEO
2 GND
'5'
VSYNC
4 HSYNC
'3'
CSYNC
6 R
7 G
8 B
7~~
3 •
S'
8 4
2
• Whenever there is any problem with the display check
if all signals are supplied to the colour encoder. Check
the waveform of VIDEO OUT.
*
Problems may arise if the colour TV is improperly
adjusted.
Signal waveform of VIDEO OUT (figures in the drawing
represents nominal values)
0- - -
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