Sharp VT-3418X, Service Manual, Page: 52 / 170

KEY-IN
VCR POWER
FLOW CHART NO. l-l
FLOW CHART NO.
The VCR
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Key-h Input is not received.
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Unplug the AC power cord.
it a few minutes later.
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Is the key switch in good contact 7
Check the switch contact.
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short-circuit in the key
NO
Check
and switches for poor
soldering.
I
S
the fuse in the TV
mother
Replace the fuse
YES
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I
YES
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I 1
Are signals received at pin of
and pin of when
l i n e s t o i n p u t o r
the key is activated
YES
Are the and lines
normal in the VCR
Is the AT line normal ?
NO
Check the AT line,
and
Are the and lines
NO
properly connected with ?
Check poor soldering.
Check and signal
of serial serial clock and
INFRARED R/C
FLOW CHART NO.
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No operation is possible from the
infrared remote control.
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YES
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1
Does the infrared remote control
function ?
control as required.
Replace the infrared remote
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Is there oscillation at pins and
of ?
Replace and /or
YES
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YES
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Is applied at pin of the
remote control receiver ?
Check the and lines.
I
t
Does pin of change
from to L level when
N O
Check pin of or
the AC cord is plugged in or ALL
CLEAR button is pressed and
released?
I
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I
YES
,
Check pin of and /or
YES
1
of
e
NO
to
level w
Check power key input to
en
the power button is pressed
and serial between
. and
YES
NO
away from the set ?
Reposition the set not to be
exposed to strong light.
YES
Is there short-circuit in the key
input or
or
?
YES
NO
Check key input terminals.
- N O
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S
the PC line normal
YES
in of connector an
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S
the PC line normal ?
YES
NO
Check
Check and signal
line of serial serial clock and
ready .
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Check wire harness to mechanism.
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