Olivetti ECR 7900 Service Manual page 37

VFD_CS0#
VFD_TXD
VFD_CLK
Trouble shooting
- Check the power supply of Display tube.
Check voltage (AC 3.9V) at point (3)
If it outputs properly - - - Replace Customer Display Unit.
If it doesn't output properly - - - Check Power supply circuit. (P.9-11)
Check voltage (DC -28V) at point (4)
If it outputs properly - - - Replace Customer Display Unit.
If it doesn't output properly - - - Check Power supply circuit. (P.9-11)
Check voltage (DC +5V) at point (5)
If it outputs properly - - - Replace Customer Display Unit.
If it doesn't output properly - - - Check Power supply circuit. (P.9-11)
Y108540-8
U6 B
19
G
11 9
A1 Y1
13 7
A2 Y2
15 5
A3 Y3
17 3
A4 Y4
TC74VHCT24 4FT
ECR 7900 Service Manual
VCC5 VCC5
R7 9 33
R8 0 33
R8 1 33
VCC5 VF2
VF1
-Vpw
FB 8
C142 1000pF
0(3 216)
C143 1000pF
R1 39
1K
CN9
1
2
3
4
5
6
7
8
B8B -PH-K-S
C1 29
EC6
+
*0.1 uF
EC 17
*100uF_50V
10u F_16 V
FB 9
0(3 216)
31
VF 1
VC C
GND
CS0#
TXD
CLK
-VPW
VF 2