Epson TM-U950 - Page 86

Rev. A Mechanism Configuration and Operating Principles 2-41
TM-U950/U950P Technical Manual
The drawer drive signal is also supplied to the IM-403/405 through CN9 for the TM-U950 only.
Print head drive circuit
The print head has nine pins that are driven by dedicated solenoids. Ports PA0 - PA7 and PB7 of
the gate array carry the solenoid signals (HEAD1 - 9). PB7 carries the common signal for the
solenoids (HD_COM). The HEAD1 - 9 signals activate the sync transistors (QM3 - QM5). The
HD_COM signal activates the source transistors (Q24, Q33, and Q34) to power the solenoids.
When the source transistors go off, the energy stored by the solenoids is dissipated via the
flywheel diodes (D39, D40, D44, D45, D46, and D47). When the sync transistors go off, the
solenoid current is cut.
Figure 2-50. Drawer Kick-out Circuit for the TM-U950
Figure 2-50a. Drawer Kick-out Circuit for the TM-U950P
1 FG
2 DKD1
3 DK S
4 DK P
5 DKD2
6 SG
1
2
3
4
5
6
CN5
R23
C9
R22
R9 R8
{ 5V
{ 24V
FG
DKD1
DKD STAT
DKD POW
DKD2
SG
U1
12
3
IO
G
D6
D4
D5
DKD1
DKD2
@ F
@ G
D
K

P
Q8
Q2
Q7
Q15
{ 5V
UNTRG-HIZ
DKD 2
SG
DKD 1
DK S
11
10
44
9
7
5
3
8
6
4
2
1
0
1
QM1
G-PS24
CPU
PS6
PS7
PE7
Gate array
CONFIDENTIAL