Sharp DV-NC55S Service Manual page 43

(VCR)
FLOW CHART NO.1
The VCR flourescent display tube fails light up.
Is the supply voltage of 5V feed to pin(7) of IC5101?
YES
Is the supply voltage of –20V feed to pin(1) of IC5101?
YES
Is it possible to confirm signals FIP CS, FIP OE,
FIP DATA, and FIP CLK on the pins(2), (3), (4)
and (5) of IC5101?
YES
Are grid and segment signals supplied to the
indication tube (DG5101) from the indication tube
driver IC (IC5101)?
YES
Is supply filament voltage feed between pin(1)/(2)
and (31)/(32) of the flourescent display tube?
YES
Check the periphery of fluorescent indication tube
and main block.
FLOW CHART NO.2
Key-in input is not received.
Does the key switch make good contact, when the
cassette tape is inserted?
YES
Is there the function control voltage inputted at the
pins(87) and (88) of IC701?
YES
Check or place the peripheral circuit of IC701.
FLOW CHART NO.3
No operation is possible from the infrared remote control.
Operation is possible from the VCR, but no
operation is possible from the infrared remote
control.
YES
Is the supply voltage of 5V feed to pin(3) terminal
of remote control receiver?
YES
Is "L" pulse sent out pin(1) terminal of receiver
when the infrared remote control is activated?
YES
Is inputted "L" pulse to pin(5) of IC701?
YES
Replace IC701.
NO
Check STBY 5V line.
NO
Check STBY –20V line.
NO
Check signal line between IC701 and IC5101.
NO
Replace IC5101.
NO
Check power circuit and D9701.
NO
Check that the fluorescent indication tube is free
from damages such as crack.
NO
Check switch contact.
NO
Check AT 5V lines.
NO
Replace the remote control receiver or replace the
remote control transmitter if necessary.
NO
Check line between at remote control receiver thru
to pin(5) of IC701.
FLOW CHART NO.4
A cassette tape is not take in.
Is "L" level applied at pin(19) of IC701.
YES
Are start sensor shutter go to openwhen the
cassette tape is inserted?
YES
Does pin(79) of IC701 change from "H" to "L"
level when the cassette tape is inserted?
YES
Does pin(11) of IC7002 go to a "H"(about 4.7V)
level when the cassette tape is inserted?
YES
Does pin(13) of IC7002 change to about 10V when
the cassette tape is inserted?
YES
Is the specified voltage (about 10V) applied at the
loading motor terminal when the cassette tape is
inserted?
YES
Replace loading motor.
FLOW CHART NO.5
A cassette tape is taken in, but ejected at once.
Does the start sensor pulse at pin(79) of IC701
change from "L" to "H" level when the cassette
tape is loaded?
YES
Does the end sensor pulse at pin(85) of IC701
change from "L" to "H" level when the cassette
tape is loaded?
YES
Does the master cam mode shifteroperate
normally when the cassette tape is loaded?
YES
Replace IC701.
FLOW CHART NO.6
The cassette tape fails to eject.
Does the capstan motor start when the EJECT
button is pressed?
YES
Does the take-up reel disk turn when the capstan
motor is running?
YES
Are pulses applied at pin(2) of IC701 when the
take-up reel disk is turning?
YES
Is a "H"(about 4.7V) level applied at pin(12) of
IC7002 when a reel pules has been inputted?
YES
Is the voltage about 10V sent out of pin(15) of IC7002?
YES
Is the specified voltage applied at the loading
motor terminal?
YES
Dose the loading motor run?
YES
Replace cassette cam, gear, etc.
NO
Check R717.
NO
Check start sensor shutter.
NO
Check line start sensor and all the way up thru to
pin(79) of IC701.
NO
Check line pin(93) of IC701 and all the way up
thru to pin(11) of IC7002.
NO
Check IC7002.
NO
Check between IC7002 and loading motor.
Check line start sensor and all the way up thru to
NO
pin(79) of IC701.
Check line end sensor and all the way up thru to
NO
pin(85) of IC701.
NO Check cam switch (A), (B) and all the way
up thru to pins(7), (6) of IC701.
NO See FLOW CHART NO.8.
<The capstan motor fails to run.>
NO
Check reel disk and reel drive unit.
NO
Check take-up reel sensor and all the
way up thru to pin(2) of IC701.
NO
Check pin(90) of IC701.
NO
Check IC7002.
NO
Check between IC7002 and all the way up thru to
the loading motor.
NO
Replace loading motor.