NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
YES
NO
YES
YES
YES
YES
YES
YES
YES
FLOWCHART NO. 1-1 FLOWCHART NO. 1-2
FLOWCHART NO. 1-3
VCR POWER TROUBLESHOOTING
The VCR is dead. (No power)
ELECTRICAL TROUBLESHOOTING
Un plug the AC power cord. Replug it
a few minutes later.
Is the fuse F1701 alright in the
TUNER/DEF. PWB ?
Are the UR 12V and UR 8.5V lines
normal in the MAIN PWB ?
Is the AT 5V line normal ?
Are the AT 5V and GND lines
properly connected with IC7701 ?
Is there oscillation at pins (38) and
(39) of IC7701 ?
Does pin (43) of IC7701 change from
"L" to "H" level after the AC cord is
plugged in or/when the RESET
button is pressed and then released ?
Does pin (21) of IC7701 change from
"L" to "H" level when the power
button is pressed to turn the power
on ? Is the PC 5V line normal?
Check wire harness to mechanism
and the sensor inputs to IC7701 from
mechanism. (CAM Switches,
start/end and reel sensors)
Replace the fuse.
Check short in the MAIN PWB.
Check fuse resistor and transistor
trouble of the power circuit in the
power PWB.
Check the AT 5V line, Q780 and
D785.
Replace the fuse.
Check poor soldering.
Check / Replace IC7701 and / or X7701.
Check the signal line of sys-con reset
all the way up to pin (60) of IC1001.
Check power key input to IC1001
and serial datas/clocks between
IC1001 and IC7701.
Check Q781 and IC780 of PC9V line.Is the PC 5V line normal ?
CASSETTE CONTROL TROUBLESHOOTING
A cassette tape is not taken in.
Is the cassette housing distored ?
Does the start sensor cover become
open when the cassette tape is
inserted ?
Does the start sensor pin (2) of
IC7701 go to "L" level when the
cassette tape is inserted ?
Does pin (5) of IC7702 go to "H" level
(about 1.8V) when the cassete tape
is inserted ?
Does pin (2) of IC7702 go to about
11V when the cassette tape is
inserted ?
Is the correct voltage at the loading
motor terminal when the cassette
tape is inserted ?
Check and replace the loading motor .
Fix or replace the cassette housing.
Check the start sensor cover.
Check the start sensor and the way
up to pin (2) of IC 7701.
Check pin (12) of IC7701 and all the
way up to pin (5) of IC7702.
Check IC7702 and UR12V line.
Check between IC7702 and the
loading motor.
A cassette tape is taken in, but ejected at once.
Does start sensor pulse at pin (2) of
IC7701 change from "L" to "H" level
when the cassette tape is loaded ?
Does end sensor pulse at pin (3) of
IC7701 change from "L" to "H" level
when the cassette tape is loaded ?
Do the cam switches A and B
operate normally when the cassette
tape is loaded ? (at pins (100) and
(1))(refer to MECHANISM flowchart)
Replace IC7701.
Check the start sensor and all the
way up to IC7701.
Check the end sensor and all the
way up to IC7701.
Check cam switches and all the way
up to IC7701.
YES
NO
NO
NO
NO
NO
NO
NO
NO
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