Service manual
26
KB-5121KS/K/W
20 INT0 IN Signal to synchronize LSI with commercial power source frequency.
This is the basic timing for all real time processing of LSI.
21 P81 OUT Signal to change the rotational direction is output to the Microwave drawer door
open-close motor.
22 TA4OUT OUT Signal to sound buzzer.
A: Key touch sound.
B: Completion sound.
C: When the oven stops so that the food can be
checked in Automatic cooking mode.
23 P77 OUT Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay(RY2). In 100%
power operation, the signals holds “H” level during
microwave cooking and “L” level while not cook-
ing. In other cooking modes (90%, 80%, 70%,
60%, 50%, 40%, 30%, 20%, 10%, 0%) the signal
turns to “H” level and “L” level in repetition accord-
ing to the power level.
24 TA3OUT OUT Signal to change the rotational speed is output to the Microwave drawer door open-close
motor.
25 TA2IN IN Plus signal coming from the Microwave drawer door open-close motor is input into TA2IN
as revolution number.
26-30 P74-P70 OUT Used for initial balancing of the bridge circuit (absolute humidity sensor).
31-33 A67-A65 OUT Terminal not used.
34 P64 IN To input signal which communicates the oven door open/close information to LSI.
Door open "H" level signal (+5V). Door close "L" level signal (GND).
35 TXD0 IN Signal coming from key unit.
36 RXD0 IN Signal coming from key unit.
37 P61 OUT Signal to reset LSI.
Signal is output to reset IC-2, IC-3 and IC-4.
38 P60 IN Signal coming from key unit.
39 RDY IN Connected to VCC2 (+3.3V).
40 ALE OUT Terminal not used.
41 HOLD IN Connected to VCC2 (+3.3V).
42 HLDA OUT Terminal not used.
43 BCLK IN Connected to VCC2 (+3.3V).
44 RD OUT Read strobe signal is outout to the LCD.
45 WRH OUT Terminal not used.
46 WR OUT Write strobe signal is outout to the LCD.
Pin No. Signal I/O Description
Microwave cooking mode
Other cooking mode
VARI MODE ON TIME OFF TIME ON TIME OFF TIME
100% power 32 sec. 0 sec. 60sec. 0ec.
90% power 30 sec. 2 sec. 54sec. 6sec.
80% power 26 sec. 6 sec. 48sec. 12sec.
70% power 24 sec. 8 sec. 42sec. 18sec.
60% power 22 sec. 10 sec. 36sec. 24sec.
50% power 18 sec. 14 sec. 30sec. 30sec.
40% power 16 sec. 16 sec. 24sec. 36sec.
30% power 12 sec. 20 sec. 18sec. 42sec.
20% power 8 sec. 24 sec. 12sec. 48sec.
10% power 6 sec. 26 sec. 4sec. 56sec.
0% power 0 sec. 32 sec. 0sec. 60sec.
A
B
C
H: +5V
L: GND
0.1 sec
2.0 sec
1.0 sec
1.0 sec
16.7 msec.
H : +5V
L : GND