Service manual

22
R-880B
29 P75 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G4 line key on matrix is touched.
30 P74 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G3 line key on matrix is touched.
31 P73 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G2 line key on matrix is touched.
32 P72 OUT Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G1 line key on matrix is touched.
33 P71 OUT Oven lamp and turntable motor driving signal(Square Waveform : 50Hz).
To turn on and off shut-off relay
(RY6). The square waveform voltage
is delivered to the relay (RY6) driving
circuit.
34 P70 IN Connected to VC.
35 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.
36 P81 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook
relay (RY2). In 100%
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.
37 P80 OUT Grill heaters (TOP HEATER) driving signal.
To turn on and off the grill heaters
relay (RY3). "L" level during grill
(TOP GRILL, TOP AND
BOTTOM) cooking, Convection
cooking or Mix top grill cooking,
"H" level otherwise.
The heater relay turns on and off
within a 48 second time base in
accordance with the special
program in LSI.
38 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.
39 XOUT OUT Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
40 VSS IN Power source voltage: -5V.
VC voltage of power source circuit input.
41 P27 OUT Bottom heater driving signal.
To turn on and off the bottom relay
(RY4). "L" level during grill (TOP AND
BOTTOM) cooking, Convection
cooking or Mix bottom cooking, "H"
level otherwise.
The heater relay turns on and off
within a 48 second time base in
accordance with the special program
in LSI.
Pin No. Signal I/O Description
Power output ON time OFF time
100 % 48 sec. 0 sec.
90 % 44 sec. 4 sec.
80 % 40 sec. 8 sec.
70 % 36 sec. 12 sec.
60 % 32 sec. 16 sec.
50 % 26 sec. 22 sec.
40 % 22 sec. 26 sec.
30 % 16 sec. 32 sec.
20 % 12 sec. 36 sec.
10 % 8 sec. 40 sec.
ON/OFF time ratio in Mi-
cro cooking
(a. 32second time base)
ON/OFF time ratio in Mi-
cro cooking
(a. 48second time base)
MICRO ON OFF
COOK
100% 32 sec. 0 sec.
70% 24 sec. 8 sec.
50% 18 sec. 14 sec.
30% 12 sec. 20 sec.
10% 6 sec. 26 sec.
MICRO ON OFF
COOK
100% 48 sec. 0 sec.
70% 36 sec. 12 sec.
50% 26 sec. 22 sec.
30% 16 sec. 32 sec.
10% 8 sec. 40 sec.
During cooking
L
H
20 msec.
Power output ON time OFF time
100 % 48 sec. 0 sec.
90 % 44 sec. 4 sec.
80 % 40 sec. 8 sec.
70 % 36 sec. 12 sec.
60 % 32 sec. 16 sec.
50 % 26 sec. 22 sec.
40 % 22 sec. 26 sec.
30 % 16 sec. 32 sec.
20 % 12 sec. 36 sec.
10 % 8 sec. 40 sec.