Adjustments and Tests167Hammer Phasing AdjustmentYou must check and adjust hammer phasing if the controller board isreplaced, 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 thevertical alignment of dots in character printing. The phase value numericalunits 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 farenough from the theoretical ideal value on a particular printer, errors canoccur. If, for example, you are adjusting phasing and an error such as PAPFIFO 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, nextto the motor housing. Adjust the phasing to this value and recheck the verticalalignment. When vertical alignment is acceptable, write the new phasingvalue 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 thePhasing Value is changed, or the New Phasing Value will not be writteninto memory. If the value is changed when not printing, the printer willreturn to its default phasing value when powered off then back on.1. Load full width (136 column) paper and set the top of form.2. Power on the printer.3. If the printer is online, press the ONLINE key to place the printer offline.Press the MENU/ENTER key and “OFFLINE / QUICK SETUP.” displays.4. On the control panel, press the U + V keys to unlock the ENTER key.“ENTER SWITCH UNLOCKED” briefly displays. (If “LOCKED” displays,simply press U and V again. This is the default key combination. Thelock/unlock key combination can be programmed by the user. If U + Vdoes not unlock ENTER, get the new key combination from the user.)5. Press the Y key. “OFFLINE / DIAGNOSTICS” displays.6. Press V. “DIAGNOSTICS / Printer Tests” displays.7. Press V. “Printer Tests / Shift Recycle” displays.8. Press Z until “Printer Tests / Phase Printer” displays.9. Press ENTER. The display shows “Printer Tests / Phase Printer” and thetest begins. The current phasing value is printed on the left of the printedpattern of all H’s. As the pattern prints, compare the H’s to the figurebelow. If the phasing needs adjustment, go to step 10. If the phasing isOK, go to step 13.NeedsAdjustment Correct NeedsAdjustment
