Chapter 6
Trouble Shooting
6-9
(9)
B2
= Lithium battery
→
Buffering of time specific parameters, real time clock component,
Nominal voltage 3,3 V -5 %
If nominal voltage drops below 2,5 V,
change lithium battery. See position 13 "Test points".
(10)
D4 = Operating system PROM
Pay attention to correct position when changing the EPROM. The
notch must point to the right side. See illustration.
(11)
X2
= Interface printer
→
Control of the needle matrix printer head
(12)
V17 = Fork light barrier for step-motor - printer spindle
(13)
X10 = Test points TP1 - TP14
The test points mentioned above may be tested with a multi-functional
test unit if it is handled with care.
For test points that are not mentioned, a test system with test
programs is necessary for a qualified test. The test runs must be
performed under dynamical conditions and therefore they cannot be
performed locally.
Attention
Pay attention when using testing spikes for a manual test!
The plug contacts of the IC-socket must not be damaged.
Always test at test point 11 against ground. A measurement
between the wrong test points will lead to a damage of the PC-
board.
TP
Designation
Measured
value
Condition
1
Lithium battery
3,3 V -5 %
Mains switch off
4
Nominal voltage U
N
4,3 V
±
5 %
Power supply on
5
Line voltage U
B
5 V
±
5 %
Power supply on
10
Real-time clock component U
RTC
3,3 V -5 %
Mains switch off
10
Real-time clock component U
RTC
5 V
±
5 %
Power supply on
11
Ground
12
Reset voltage U
R
5 V
±
5 %
Power supply on
(14)
S1
= Mains switch
(15)
X5
= Terminal for battery pack, option
By connecting the battery pack pay attention that the right poles are
used.
+ = red, - = black.
(16)
X4
= Interface for connection to external PC.
