Head Temperature Detect Circuit; Cutter Home Position Sensor Circuit; Reset Circuit - Brother TD-4000 Service Manual

2.3.6

Head Temperature Detect Circuit

TD-4000/4100N measures the following temperature.
- Head temperature: The CPU determines the ambient temperature of the head from the
2.3.7

Cutter Home Position Sensor Circuit

TD-4000/4100N identifies open/close of the cutter from the status of mechanical switch.
Closing the cutter, the cutter home position sensor opens.
The change of status is sent as the signal through CN14 to CUTSEN (74 pin) of the CPU.
TD-4000/4100N first confirms that the cutter stays on its' home position prior to printing.
When the cutter returns to the home position, the cutter home position sensor circuit
recognizes it and stops the DC motor rotation.
2.3.8

Reset Circuit

TD-4000/4100N receives the electric power from the power supply PCB and output +5V
and +3v to the CPU.
When the power is supplied, the reset circuit (U13) returns high to reset input pin (66pin)
of the CPU when detecting the voltage the +3V voltage line rises over +2.8V. This input
releases the reset status of CPU.
If the +3V voltage line drop to +2.8V or lower due to any reason during operation, the
reset circuits returns Low signal to the CPU and the CPU goes to the reset status.
AD converted voltage value input to TH (78pin) of the CPU via CN11.
Figure 2.3-8 Head Temperature Detect Circuit
Figure 2.3-9 Cutter Home Position Sensor Circuit
Figure 2.3-10 Reset Circuit
II - 16