Read Sharp DV-NC70H (serv.man5) Service Manual online
52
DV-NC65H/S
DV-NC70H
DV-NC70H
FLOW CHART NO.7
Does the key switch make good contact, when the
cassette tape is inserted?
Check switch contact.
Is there the function control voltage inputted at the
pins(88) and (89) of IC701?
NO
YES
Check or replace the peripheral circuit of IC701.
YES
Key-in input is not received.
FLOW CHART NO.8
Operation is possible from the VCR, but no
operation is possible from the infrared remote
control.
Is the supply voltage of 5V fed up to pin(3) terminal
of remote control receiver?
Check AT 5V lines.
Is "L" pulse sent out from pin(1) terminal of receiver
when the infrared remote control is activated?
Replace the remote control receiver or replace the
remote control transmitter if necessary.
Is "L" pulse inputted to pin(4) of IC701?
Check line between remote control receiver thru
to pin(4) of IC701.
Replace IC701.
NO
NO
NO
YES
YES
YES
YES
No operation is possible from the infrared remote control.
FLOW CHART NO.9
Are start sensor shutter go to open when the
cassette tape is inserted?
Check start sensor shutter.
NO
YES
Does pin(87) of IC701 change from "H" to "L" level
when the cassette tape is inserted?.
Check between start sensor and pin(87) of IC701.
NO
YES
Does pin(10) of AC connector become to "H" level
(4.7V) when the cassette tape is inserted?
Check between pin(92) of IC701 and pin(10) of
AC connector.
NO
YES
Is the specified voltage (about 10V) applied at the
loading motor terminal when the cassette tape is
inserted?
Replace capstan motor unit.
NO
YES
Replace loading motor.
A cassette tape is not take in.
FLOW CHART NO.10
Does the start sensor pulse at pin(87) of IC701
change from "L" to "H" level when the cassette
tape is loaded?
Check line start sensor and all the way up thru to
pin(87) of IC701.
Does the end sensor pulse at pin(86) of IC701
change from "L" to "H" level when the cassette
tape is loaded?
Check line end sensor and all the way up thru to
pin(86) of IC701.
Does the master cam mode shifter operate
normally when the cassette tape is loaded?
Check cam switch (A), (B) and all the way
up thru to pins(94), (93) of IC701.
Replace IC701.
NO
NO
NO
YES
YES
YES
A cassette tape is taken in, but ejected at once.
FLOW CHART NO.11
Does the capstan motor start when the EJECT
button is pressed?
See FLOW CHART NO.13.
<The capstan motor fails to run.>
Does the take-up reel disk turn when the capstan
motor is running?
Check reel disk and reel drive unit.
Are pulses applied at pin(2) of IC701 when the
take-up reel disk is turning?
Check take-up reel sensor and all the
way up thru to pin(2) of IC701.
Replace cassette cam, gear, etc.
NO
NO
NO
YES
YES
YES
Is a "H" level (about 4.7V) applied at pin(10) of AC
connector when a reel pulse has been inputted?
Check pin(92) of IC701.
NO
YES
YES
Is the specified voltage applied at the loading
motor terminal?
Change the capstan motor unit.
NO
Does the loading motor run?
Replace loading motor.
NO
YES
The cassette tape fails to eject.
FLOW CHART NO.12
Does power control(H) signal at pin(96) of IC701
change from "L" to "H" level?
Check IC701.
Does the base of Q1905 change from about 5V
to 4.5V?
Check the pin(96) of IC701 and all the way up thru
to Q1905.
Is 5V sent out of the emitter of Q1905?
Check Q1905 and the AT 5V line.
NO
NO
NO
YES
YES
No power is turned on.
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