Battery Circuit - Olivetti ECR 7900 Service Manual

3-12. BATTERY CIRCUIT

VBB voltage is used by CPU, external RAM and FROM.
It is supplied by dry battery at the time of back-up.
Battery specification
Type : AA x 3pcs
Voltage: 4.5V
CAUTION;
RISK OF EXPLOSION IF BATTERY IS REPLACED BY AN INCORRECT TYPE.
DISPOSE OF USED BATTERIES ACCORDING TO THE INSTRUCTIONS.
VCC3
D16
1SS 355
D17
1SS 355
D18
1SS 355
R203
39
R205
B
750
R204
62
Trouble shooting
- Check whether the batteries are supplied in the battery box.
- Check the voltage of each battery. (It should be over 1.1V per battery.)
It outputs less than 1.1V per battery (less than 3.3V with 3 batteries) - - - Replace the battery.
It outputs over 1.1V per battery (over 3.3V with 3 batteries). - - - Check the voltage at point (1).
- Check the voltage at point (1)
It outputs almost same voltage as battery voltage - - - Replace Main Board.
It outputs much less than the battery voltage or 0V - - - Replace Battery unit.
36
VBB
R200
10K R201
*10K
Q14
2SC 2412K
ECR 7900 Service Manual
U13 XC 6215
1 4
CE VIN
2 3
VSS VOUT
C140
1uF
VBB
R202
0
(1)
C28
0.1uF
Y108540-8
CN13
2
1
B2B -XH-A