Read Sharp VC-MH834 (serv.man3) Service Manual online
42
VC-M314HM
VC-MH834HM
VC-MH834HM
Is the cassette housing
distorted?
NO
YES
YES
YES
YES
NO
YES
NO
NO
YES
NO
YES
FLOW CHART NO.8 CASSETTE CONTROL
TROUBLESHOOTING(1)
A
cassette tape is not take in.
NO
NO
Check start sensor cover
.
Check line between start sensor
and pin(79) of IC701.
Check line between pin(93) of
IC701 and pin(1
1) of IC7002.
Is the supply voltage of 12V fed
to pin(9) of IC7002?
Check M 12V lines.
Check IC7002.
Check line between IC7002 and
loading motor
.
Replace loading motor
.
Is the specified voltage applied
at the loading motor terminal
when the cassette tape is inserted?
Does pin(13) of IC7002 change to
about 10V when the cassette
tape in inserted?
Does pin(1
1) of IC7002 go to a
"H" level when the cassette tape
is inserted?
Does pin(79) of IC701 change
from "H" to "L" level when the
cassette tape is inserted?
Does the start sensor cover go
to open when the cassette tape
is inserted?
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(87) and (88) of
IC701, when the keys are activated?
Replace IC701.
Check peripheral circuit of pins(87) and
(88) of IC701, and the function keys.
YES
NO
NO
YES
Key-in input is not received
SWITC
FUNCTION
SWITC
FUNCTION
Ref No. Ref No.
NOP
NOP
5.000V
SW889
REW
P801
CASSETTE
4.279V
SW893
FF
NOP
3.694V
SW892
REC
SW817
SP/LP/EP
3.081V
SW894
PLA
Y
P802
TEST
2.561V
SW891
P
AUSE
SW816
CH+
1.864V
SW890
ST
OP
SW814
MENU
1.250V
SW810
SET
SW81
1
EJECT
0.625V
SW815
CH(-)
SW813
POWER
0.000V
KEY
-1 IN
KEY
-0 IN
TERMINAL
(Pin87 of IC701)
(Pin88 of IC701)
VOL
T
AGE
FLOW CHART NO.7 INFRARED R/C TROUBLESHOOTING
No operation is possible from the infrared remote control.
Dose the infrared remote control
function?
Replace infrared remote control
as required.
Is the supply voltage of 5V fed to
pin(3) of RMC831.
Check
A
T
5V and GND lines.
Is "L" pulse sent out from pin(1) of
the receiver when the infrared remote
control is activated?
Replace receiver
.
Check between at pin(1) of receiver
and all the way up thru to pin(5) of
IC701.
Replace IC701.
YES
NO
YES
NO
NO
NO
YES
A/D KEY
INPUT
SPECIFICA
TION:-
FLOW CHART NO.6 TIMER TROUBLESHOOTING (2)
Fix or replace the cassette
housing.
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