Read Sharp R-8740 (serv.man9) Service Manual online
R-8740M - 24
Pin No.
Signal
I/O
Description
ON/OFF time ratio in Micro
cooking
(a. 32second time base)
(a. 32second time base)
ON/OFF time ratio in Micro
cooking
(a. 48second time base)
cooking
(a. 48second time base)
MICRO
ON
OFF
COOK
100%
100%
32sec.
0sec.
70%
24sec.
8sec.
50%
18sec.
14sec.
30%
12sec.
20sec.
10%
6sec.
26sec.
MICRO
ON
OFF
COOK
100%
100%
48sec.
0sec.
70%
36sec.
12sec.
50%
26sec.
22sec.
30%
16sec.
32sec.
10%
8sec.
40sec.
19
P47
OUT
Grill heater (TOP HEATER) driving signal.
To turn on and off the grill heater relay
(RY3). "L" level during grill (TOP
GRILL, TOP AND BOTTOM) cooking
or dual (MICRO + TOP) cooking or
convection cooking. "H" level
otherwise.
To turn on and off the grill heater relay
(RY3). "L" level during grill (TOP
GRILL, TOP AND BOTTOM) cooking
or dual (MICRO + TOP) cooking or
convection cooking. "H" level
otherwise.
20
P46
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook
relay (RY2). In 100%
POWER operation, the
signals hold "L" level during
microwave cooking and "H"
level while not cooking. In
other cooking modes (70%,
50%, 30%, 10%) the signal
turns to "H" level and "L"
level in repetition according
to the power level.
To turn on and off the cook
relay (RY2). In 100%
POWER operation, the
signals hold "L" level during
microwave cooking and "H"
level while not cooking. In
other cooking modes (70%,
50%, 30%, 10%) the signal
turns to "H" level and "L"
level in repetition according
to the power level.
21
P45
OUT
Memory (I-2) clock output.
22
P44
IN/OUT
Memory (I-2) data input/output.
23
INT1
OUT
Terminal not used.
24
INT0
IN
Signal to synchronized LSI with commercial power source
frequency(50Hz).
This is basic timing for time processing of LSI.
frequency(50Hz).
This is basic timing for time processing of LSI.
25
P41
IN
Terminal not used.
26
P40
IN
Connected to VC.
27
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
Temporarily set to "L" level the moment power is applied, at this time the LSI
is reset. Thereafter set at "H" level.
Signal is input to reset the LSI to the initial state when power is applied.
Temporarily set to "L" level the moment power is applied, at this time the LSI
is reset. Thereafter set at "H" level.
28-29
P71-P70
OUT
Terminal not used.
30
XIN
IN
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation
circuit with respect to XIN terminal.
The internal clock frequency is set by inserting the ceramic filter oscillation
circuit with respect to XIN terminal.
31
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
Output to control oscillation input of XOUT.
32
VSS
IN
Power source voltage: -5V.
VC voltage of power source circuit input.
VC voltage of power source circuit input.
33-36
P27-P24
OUT
Terminal not used.
37
P23
IN
Signal coming from touch key.
When any one of G4 line keys on key matrix is touched, a corresponding
signal from P17 - P12 will be input into P23. When no key is touched, the
signal is held at "H" level.
When any one of G4 line keys on key matrix is touched, a corresponding
signal from P17 - P12 will be input into P23. When no key is touched, the
signal is held at "H" level.
38
P22
IN
Signal similar to P23.
When any one of G3 line keys on key matrix is touched, a corresponding
signal will be input into P22.
When any one of G3 line keys on key matrix is touched, a corresponding
signal will be input into P22.
39
P21
IN
Signal similar to P23.
When any one of G2 line keys on key matrix is touched, a corresponding
signal will be input into P21.
When any one of G2 line keys on key matrix is touched, a corresponding
signal will be input into P21.
40
P20
IN
Signal similar to P23.
When any one of G1 line keys on key matrix is touched, a corresponding
signal will be input into P20.
When any one of G1 line keys on key matrix is touched, a corresponding
signal will be input into P20.
DESCRIPTION OF LSI
LSI(IX091DR)
The I/O signal of the LSI(IX091DR) are detailed in the following table.
The I/O signal of the LSI(IX091DR) are detailed in the following table.
ON
OFF
During
cooking
L
GND
H.
(Grill,dual or convection)
20 msec
H : GND
L (-5V)
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