Epson PhotoPC 800, Руководство по обслуживанию

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EPSON PhotoPC 800 Revision A
Operating Principle Operating principles of the Circuit Boards 39
2.2.1.6 Lens Drive Clock
†
Shutter drive:
The two control signals (SIN1, SIN2) which are output from the ASIC
expansion port (IC106) are converted into drive pulses (SOUT1, SOUT2)
by the motor drive (IC951), and the shutter is opened and closed by regular
current drive.
Table 2-3. Shutter specification
†
Iris drive
The two control signals (IIN1, IIN2) which are output from the ASIC
expansion port (IC106) are converted into drive pulses (IOUT1, IOUT2) by
the motor drive (IC952), and the iris is opened and closed. Resistance
R9505, which is connected to IOUT2 of IC952 in series, is the current
control resistance for the minimum drive voltage of the iris motor.
Table 2-4. Iris specification
†
Focus drive
The four control signals (FIN1, FIN2, FIN3 and FIN4) with different phases
which are output from the ASIC are converted into drive pulses (FOUT1,
FOUT2, FOUT3 and FOUT4) by the motor driver (IC953), and are then
used to drive the stepping motor for focusing operation. Detection of the
standard focusing positions is carried out by means of the photointerruptor
(FOCUS PI) inside the lens block.
Table 2-5. Focus Motor specification
Table 2-6. Detection of Focus position
Item Contents
Method 2-spring shutter
Current for motor driving Maximum 200mA
Motor coil resistance 12
±
1
Ω
(at normal temperature)
Item Contents
Focus step 2 steps (when F2.8 opens, F8)
Minimum drive voltage 1.4VDC
Motor coil resistance 12
±
1
Ω
(at normal temperature)
Item Contents
Method Stepping Motor
Driving voltage 3.4
±
1V
Driving frequency 480bps
Motor coil resistance 40
Ω ±
7% (at normal temperature)
Item Contents
Method Photo interrupter type
Driving voltage 5V
Judgement
• High: higher than 3.5V
• Low: less than 1.5V