Sharp VC-AA350A

37
VC-AA350A/L/M/W
VC-AA352W,AA360A,AA370A
VC-AA550A/L/W,AA560A,AA570A
FLOW CHART NO.7 KEY CONTROL TROUBLESHOOTING
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.>
SWITC FUNCTION SWITC FUNCTION
VOLT.REF.
Ref No. Ref No.
S805 SET S801 POWER 0.000V
S806 CH(+) S802 EJECT 0.652V S807
T.Speed/PAUSE
S803 MENU 1.250V / 1.864V
S808 PAUSE/REC S804 CH(-) 1.864V /
2.561
V
S883
REC S881 PLAY 2.561V
S884/S885 REW S882 STOP 3.081V S886/S887 FF No Use No Use 3.694V No Use No Use TP801 TEST 3.712V No Use No Use TP802 CASSETTE 4.285V
KEY-1 IN KEY-0 IN (Pin88 of IC701) (Pin89 of IC701)
A/D KEY INPUT
SPECIFICATION:-
FLOW CHART NO. 6 TIMER TROUBLESHOOTING
The LCD display fails to light up.
Is the supply voltage of 5V fed to pin(37) of IC8001?
Check AT 5V line.
Is the supply voltage of 3.4V, 1.7V feed to pin(38) and pin(39) of IC8001?
Check pin(38), (39) of IC8001 and peripheral circuits.
Is it possible to confirm signals LCD RESET, LCD CS, LCD CLOCK and LCD DATA on the pins(36), (42), (43) and (44) of IC8001?
Are the segment signals supplied to the LCD display (LC8001) fromthe driver IC (IC8001)?
Check peripheral circuit of pin(41) of IC8001.
Check that the LCD display is free from damages such as crack.
Replace IC8001.
YES
YES
YES
YES
NO
NO
NO
NO
NO
Check the signal line between
IC701 and IC8001.
YES
IC8001 present?
Is the OSC signal at pin(41) of