IBM 4247, Maintenance Information

Page: 293 / 567

1. If the FIXED=1 sample is light, the FIXED=2 sample is very light (missing dots), and the FIXED=3 sample is
unreadable (due to lightness) the gap is too large.
2. Using T&D12, decrease the T&D12 adjustment value -2, and STORE, to decrease the wheel position 0.5.
3. Rerun the samples to verify satisfactory results, and go to “Gap Check”.
Gap Check: Perform this check only after completing the “Power Off Check” on page 286, the “Power On
Check” on page 289, and the “Print Quality Check” on page 291.
After the print quality samples indicate that the printer now has achieved the proper darkness change, you must
verify a correct gap between the:
v
Printhead and the platen
v
Carriage and the platen
To verify the correct gaps, follow these steps.
1. Set the AFTA menu item to AFTA=0.
2. Load a single sheet of 20 lb (80 g/m
2
) paper into the print area.
3. Remove the forms from the forms path.
4. Remove the ribbon cartridge.
Checking Printhead-to-Platen Gap
1. Rotate the platen to locate a white dot on the left end of the platen shaft.
If you can locate the white dot, you will use a 0.25 mm (0.010 in.) feeler gauge in the next step.
- or -
If you cannot locate the white dot, you will use a 0.3 mm (0.012 in.) feeler gauge in the next step.
2. Check the gap between the printhead needles and the platen, using one of the feeler gauges.
3. If the resistance is slight, proceed to Checking Carriage Casting-To-Platen Gap. If the resistance is
excessive, the gap is too small because the needles are worn. Replace the printhead, and return to “Power
On Check” on page 289.
Chapter 5. Removals and Adjustments
293