Platen Gap Adjustment (Figure 35)
IMPORTANT Only do this procedure if the original equipment shuttle frame assembly or platen has been replaced by a new or
1. Prepare the printer for maintenance (page 338).
2. Remove the shuttle cover assembly (page 357).
3. Loosen the platen open belt (page 415, steps 2, 3, and 4).
4. Raise the forms thickness lever (1) to the fully open position.
5. If you are adjusting any model except the 6400-i20, select a 0.011 inch (0.28mm) flat feeler gauge.
If you are adjusting a 6400-i20, select a 0.012 inch (0.30 mm) flat feeler gauge.
ATTENTION Do not force the platen against the feeler gauge. Damage to the hammer tips will result.
6. Insert the feeler gauge (2) straight down between the hammer bank cover plate (3) and ribbon mask (4), within four
hammer positions of the left end of the hammer bank.
ATTENTION Adjust the platen set screws less than 1/4 turn on one side, then check the other side. Adjustment sensitivity is
approximately 0.03 inch per revolution of the set screw. Also, insert the feeler gauge no more than two inches down
from the top of the ribbon mask.
7. Gently close the forms thickness lever (1). As the platen is closing, gently slide the feeler gauge up and down, keeping it
between the hammer tips and ribbon mask. If the feel is too tight as the platen closes, adjust the 3/32 inch set screw (5)
counterclockwise. If the feel is too loose, adjust the set screw clockwise. With the forms thickness lever closed all the way,
the feeler gauge should contact both the tips and the ribbon mask and move with light friction. Shift the gauge slightly to
8. Repeat steps 4 through 7 at the right end of the hammer bank.
9. After adjusting both sides, check the gap again at both ends. Readjust if necessary.