Sharp VC-MH705HM/LM

42
VC-MH705HM/LM VC-MH815HM/LM,MH85HM VC-MH715HM,MH835HM
FLOW CHART NO.7 KEY CONTROL TROUBLESHOOTING(2)
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, when the keys are activated?
Replace IC701.
Check peripheral circuit of pins(88)
and (89) of IC701, and the function
keys.
YES
NO
NO
YES
Key-in input is not received 
<Except for jog shuttle mode.>
FLOW CHART NO.8 INFRARED R/C TROUBLESHOOTING
No operation is possible from the infrared remote control.
Does the infrared remote control
function?
Replace infrared remote control as
required.
Is the supply voltage of 5V fed to pin(2)
of RMC801?
Check AT 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 through to pin (4) of IC701.
Replace IC701.
YES
NO
YES
NO
NO
NO
YES
Is the cassette housing distorted?
Fix or replace the cassette housing.
NO
YES
YES
YES
YES
NO
YES
NO
NO
YES
NO
YES
FLOW CHART NO.9 CASSETTE CONTROL TROUBLESHOOTING(1)
A cassette tape is not take in.
NO
NO
Check start sensor cover.
Check line between start sensor and
pin (87) of IC701
Check line between pin (92) of IC701
and pin(10) of P701.
Is the supply voltage of 12V fed to pin
(8) of P701?
Check M 12V lines.
Check IC on mechanism.
Check line between IC on mechanis
and loading motor.
Replace loading motor.
Is the specified voltage applied at the
loading motor terminal when the cassette
tape is inserted?
Does IC on mechanism output to about
10V when the cassette tape in inserted?
Does pin(87) 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?
SWITC FUNCTION SWITC FUNCTION TERMINAL
Ref No. Ref No. VOLTAGE
S805 SET S801 POWER 0.000V
S806 CH(+) S802 EJECT 0.652V
S807 TAPE SPEED / PAUSE  S803 MENU 1.250V / 1.864V
S808 PAUSE / REC  S804 CH(-) 1.864V / 2.561V
S883 REC / NO USE  S881 PLAY
S884/S885 REW S882 STOP 3.081V
S886/S887 FF TP801 TEST 3.694V
- - TP802 CASSETTE 4.279V
- - - - 5.000V
KEY-1 IN KEY-0 IN
(Pin88 of IC701) (Pin89 of IC701)
Does pin(10) of P701 go to a "H" level
when the cassette tape is inserted?
YES
YES
YES
NO
NO
NO
FLOW CHART NO.6 POWER TROUBLESHOOTING(6)
In case of output voltage at low level.
Check peripheral circuits IC901, IC903,
C9336, R932, R930 and R933.
The result of IC901, IC903, C9336, R932,R930 and
R933. Replace where necessary.
Check C901 and peripheral circuits of
IC901.
Replace IC901.
Check short-circuit or leak of T901.
Replace T901.
Check primary circuit and peripheral
circuit of Q901 and Q902.
www.freeservicemanuals.info
6/17/2019
Digitized in Heiloo the Netherlands
Not for sale!