Hammer Phasing Adjustment - Printronix P5000 Maintenance Manual

Chapter 4

Hammer Phasing Adjustment

Hammer Phasing Adjustment

You must check and adjust hammer phasing if the controller board is
replaced, the shuttle frame assembly is removed, or if the MPU is replaced.
The hammer phase value is a timing parameter that permits you to adjust the
vertical alignment of dots in character printing. The phase value numerical
units are relative; they do not represent a physical measurement or value.
Thus there is no "correct" value or range. But, if the phasing value is far
enough from the theoretical ideal value on a particular printer, errors can
occur. If, for example, you are adjusting phasing and an error such as PAP
FIFO UNDRFL* occurs, the phase value may be too high. Try a lower value.
The factory prints the initial phase value on the shuttle assembly casting, next
to the motor housing. Adjust the phasing to this value and recheck the vertical
alignment. When vertical alignment is acceptable, write the new phasing
value on the shuttle.
Phasing should be adjusted with the printer printing at full paper width.
IMPORTANT
The printer must be printing the Phase pattern of "H's" when the
Phasing Value is changed, or the New Phasing Value will not be written
into NVRAM. If the value is changed when not printing, the printer will
return to its default phasing value when powered off then back on.
1. Raise the printer cover.
2. Install the ribbon.
3. Load full width (136 column) paper and set the top of form.
4. Power on the printer.
5. If the printer is on-line, press the ON LINE key to place the printer off-line.
"OFFLINE / CONFIG. CONTROL." displays.
6. On the control panel, press the
"ENTER SWITCH UNLOCKED" briefly displays. (If "LOCKED" displays,
simply press
unlock key combination can be programmed by the user. If
not unlock ENTER, get the combination from the user.)
7. Press the
8. Press
9. Press
10. Press
11. Press ENTER. The display shows "Printer Tests / Phase Printer" and the
test begins. The current phasing value is printed on the left of the printed
pattern of all H's. As the pattern prints, compare the H's to the figure
below. If the phasing needs adjustment, go to step 12. If the phasing is
OK, go to step 15.
148
=
= >
and again. This is the default key combination. The lock/
;
key. "OFFLINE / DIAGNOSTICS" displays.
>
. "DIAGNOSTICS / Printer Tests" displays.
>
. "Printer Tests / Shift Recycle" displays.
;
until "Printer Tests / Phase Printer" displays.
>
+ keys to unlock the ENTER key.
= >
+ does