Brother PT-1090 Service Manual page 64

PRINT1 submode (5 key*)
(*You may switch back to this PRINT1 submode from any other submode by
pressing the 5 key, except during the key depressing test in the KEY submode.)
With the "PRN1" displayed, the machine is in the PRINT1 submode.
Press the key. The machine prints the test pattern as given below.
The print length should be 106.7 ±5 mm.
After completion of printing, the machine automatically initializes the internal
memory and enters CUT submode.
If the print length is out of the specified range, adjust the variable resistor on the
main PCB by using a flat screwdriver as shown below.
If the print length is out of the specified range:
1) Remove the seven screws (shown on page III-4) from the bottom cover and
separate the bottom cover from the upper cover as shown on the next page to
access the variable resistor on the main PCB.
2) Rotate the variable resistor on the main PCB by using a flat screwdriver.
3) After the adjustment, print a test pattern again in the PRINT1 submode and
confirm the print length.
Variable resistor
(Motor drive control)
Upper cover
Main PCB ASSY
Figure 3.2-2 Adjusting the Print Length by Rotating the Variable Resistor
III - 42