Service manual

CHAPTER 4. HARDWARE DESCRIPTION
1. OUTLINE
• CPU: uPD780023A (ROM 24KB, RAM 1024B)
• KEY BOARD: 30key including PF key
• MODE SW: 5position slide SW
DISPLAY: 7seg.+DP x 8digit LED (YELLOW GREEN) FRONT only
• DRAWER: 1ch, no open sensor
• BUZZER: 1beep, piezo buzzer
• PRINTER: M-31(no EURO SYMBOL)
2. BLOCK DIAGRAM
3. DISCRIPTION
1) DISPLAY
(Output Timing of STROBE signal)
2) KEYBOARD and MODE SW
MODE SW, KEY MATRIX is follows.
Note: Although the XE-A101 has 30 keys, the keyboard circuit is
actually 32 keys (+) the PF key.
3) BUZZER
The BUZZER is driven by the P75/BUZ signal of the CPU.
Frequency : 4.095kHz
6V
CPU
uPD780023A
D
Printer
M-31
RAWER
KE Y
BOARD
&
MODE SW
8. 8. 8. 8. 8. 8. 8.
FRONT display :8digit
POWER
SUPPLY
AC
5V
ST1- ST4-,ST5
A1 G1,DP1,A2 G2~,DP2
KST1 KST8
KR1 KR6
8.
BUZZER
MA IN
4.19MHz
For Clock
32.768kHz
Battery
5V
ST4- ST3- ST2- ST1-
ST1-
ST2-
ST3-
ST4-
1ms
30~100us
Display
strobe
1 2 3 4 5
SLIDE SW
REG
POWER
OFF
VOID X/F Z/PGM
22
31 7
15 16
24 25
26 1 2
8 9 10
17 18 19
27
28
3 4
11 12
21
30
5 6
13 14
32
SW1
MODE SW
KST2
KR1
KST3
KST4
KST5
1
2
3
4
5
6 7 13 25
D13 1SS133 KST1
1 2 8 14
D14 1SS133 KST2
11 12 19 9
D15 1SS133 KST3
17 18 3 23
D16 1SS133 KST4
28 24 20 10
D17 1SS133 KST5
30 26 21 4
D18 1SS133 KST6
32 22 15 5
D19 1SS133 KST7
29 31 27 16
D20 1SS133 KST8
KST1
1
2
3
4
5
6
7
8
9
KCN2
KR2 KR6 KR5 KR4 KR3
KEYBOARD