Solder Points; Logic And Vh Power, And Related Circuits - Brother PT-9200DX Service Manual

3.2.2

Solder Points

Fig. 3.2-3 shows the solder point circuit.
One of solder points L-S is soldered according to the resistance level of the thermal
head.
After the power is turned on, AN0 and AN3 are read to judge the soldering point in
combination with the voltage level.
After the soldering point has been changed, check if solder is completely removed
from the soldering point, using a multimeter or the like.
3.2.3

Logic and VH Power, and Related Circuits

Power from a commercially available wall outlet is Vcc (+5V±0.25V) which is
supplied to the main PCB, and then to all logic components.
When Vcc is supplied, the reset IC (Q5) switches the reset signal level to high to
start the CPU.
When the CPU starts after the power is supplied, ports are initialized, and the CPU
enters the sleep state (the power is turned off).
With the power off, pressing the [ON/OFF] key causes the interruption of NMI to
start the CPU, turning on the power.
With the power on, pressing the [ON/OFF] key places the CPU in the sleep state
(the power is turned off).
With the machine in operation, P81 is switched to high to turn on Q9 (FET),
supplying VH to the thermal head, the full cutter motor, the half cutter motor, and
the tape feed motor.
Fig. 3.2-3 Solder Point Circuit
III - 5