SCP SCIENCE DigiPREP - Keypad Malfunction Troubleshooting

SCP SCIENCE
22
KeyPad
Version 1.0
KEYPAD MALFUNCTION
The KeyPad is made of 16 independant
switches. The information of a pressed button is
sent to the CPU with help of a row and
column detector. One should feel a "soft click" upon
pressing a button.
ROW4
GND GND
GND
GND
R49
R23
R50
R22
R51
R21
R52
R20
C33
C32
C31
C30
5Vdc
10K
10K
10K
10K
100
100
100
100
1nF
1nF
1nF
1nF
R16
100
R17
100
R19
100
R18
100
RJ7
ROW 3
RJ6
ROW 2
RO W1
RJ5
RJ4
1
4
7
Shift Left
2
5
8
0
3
6
9
Shift Right
Alarm Temperature
Time
Enter
COL4
GND
C29
1nF
CO L1
GND
C26
1nF
CO L2
GND
C27
1nF
CO L3
GND
C28
1nF
FIGURE 8: KEYPAD ELECTRONIC DIAGRAM