HP LaserJet Enterprise 500 Maintenance Manual - Page 121

Hammer Phasing Adjustment

Page 121 highlights

List of Adjustments Hammer Phasing Adjustment You must check and adjust hammer phasing if the CMX 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 aluminum casting of the shuttle assembly, 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. Note 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 online, press the ON LINE key to place the printer offline. "OFFLINE / CONFIG. CONTROL." displays. 6. On the control panel, press the = + > keys to unlock the ENTER key. "ENTER SWITCH UNLOCKED" briefly displays. (If "LOCKED" displays, simply press = and > again.) 7. Press the ; key. "OFFLINE / DIAGNOSTICS" displays. 8. Press >. "DIAGNOSTICS / Printer Tests" displays. 9. Press >. "Printer Tests / Shift Recycle" displays. 10. Press ; until "Printer Tests / Phase Printer" displays. 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. 121

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List of Adjustments
121
Hammer Phasing Adjustment
You must check and adjust hammer phasing if the CMX 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 aluminum casting of the
shuttle assembly, 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.
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 online, press the
ON LINE
key to place the printer offline.
“OFFLINE / CONFIG. CONTROL.” displays.
6.
On the control panel, press the
=
+
>
keys to unlock the
ENTER
key.
“ENTER SWITCH UNLOCKED” briefly displays. (If “LOCKED” displays,
simply press
=
and
>
again.)
7.
Press the
;
key. “OFFLINE / DIAGNOSTICS” displays.
8.
Press
>
. “DIAGNOSTICS / Printer Tests” displays.
9.
Press
>
. “Printer Tests / Shift Recycle” displays.
10. Press
;
until “Printer Tests / Phase Printer” displays.
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.
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.
Note