TallyGenicom T2265, Maintenance Manual

Page: 59 / 190

Functional Description Electronic Functions
3-39
3.3.23
Printhead
This modern ballistic printhead is driven by the needle driver section on the main
board (FT5763M, signals N1x–N24x).
The needle control is performed by the PPU96 (47537).
General:
The system to shoot a needle is activated by a current through a coil of the system.
One end of each coil of the needle magnet is connected to the voltage UN (+33) V
via the head cable. The return lines of the other ends of the coils are connected to the
needle drivers of the driver board. In the needle driver chip; controlled by the pro-
gram; the return lines are connected for a short time to GND. If the expected needle
current is reached the current will be chopped by hardware control.
The printhead is connected to X2 and X14 on the Connection Board. (Take care not
to loosen the pull relief clamp at the plugs when replacing printhead!).
2280+ Printhead:
The 2280+ printer is now equipped with a new printhead NDK9+. This
printhead
contains an EEPROM (printhead chip). This EEPROM stores the calibrati
on
settings of the coils for the printhead temperature control and the number of firings
for every single needle (dot counter). The chip is also used for detection of the
NDK9+.
Printhead detection (2280+ only)
After powering on the printer the ROM of the DS2433 (printhead chip) is read and the
family code and checksum is verified. If the printhead chip is detected properly and
the logic board and connection board has a "+" identification, the printer will start nor-
mally, in all other cases it will display "Hardware Alarm, Wrong Board". This message
will also appear if the printhead chip is defective or the corresponding wire in the trai-
ling cable is broken.
Papier
Paper
Farbband
Ribbon
Needle Guide
Nadel
Nadelführung
Needle
Gegenlage
Platen
Druckkopf
Print head
Ballistic
Fuss
Foot
Magnet
Elektro-
magnet
Spring
Feder
Klappanker
Anchor