Powering
CompactFlash media must be present in the 744T upon FireWire connection to be properly mounted by the host computer. CF media may not be “hot-swapped” after mounting—directory corruption may occur. If the CF slot is empty when the 744T is connected to the host system, a drive letter will still be assigned, but will not be accessible.
To connect the 744T for FireWire transfer:
1.Stop all playback and recording activity.
2.Interconnect the 744T to the host computer.
3.The 744T will now show COMPUTER CONNECTION in the LCD. While audio will still pass through the 744T, no recording or playback is possible.
4.Navigate the drives on the computer and copy all needed audio to local storage.
To avoid possible directory corruption on the 744T internal media, always properly dismount the drives from the operating system. On Mac platforms, drag the drive icons to the trash. On Windows platforms, use the “Disconnect External Media” icon in the system tray.
Powering
The 744T is powered from either a removable, rechargeable Li-on battery or external DC power. The included 7.2 V Li-on cell can be used as either primary or backup power. The unit automatically chooses the power source depending on the voltage levels of the removable battery and external sources. The switch between external and removable battery is seamless and does not affect recording or playback.
One of the hallmarks of Sound Devices’ equipment is its power efficiency. During normal operation using the rechargeable cell the 744T will run for approximately two hours (1500 mAh Li-on battery).
Lithium Ion Rechargeable Battery
The 744T is powered from Sony-compatible L- or M-type Li-on battery cells. Numerous battery capacities are available in these battery mounts, ranging from 1000 mAh to 6000 mAh. The 744T’s mount can accommodate a variety of cells since the back panel mount accommodates unlimited battery depth. Larger amp-hour cells provide more run time.
When powered by the removable rechargeable battery, the LCD display shows the battery voltage level. The nominal operating voltage for the rechargeable battery is 7.2 V, with operating voltages from 6.5–8.5 V. When the battery drops to 6.5 V, battery voltage display in the LCD and the power LED begins flashing, warning that the battery is nearly exhausted. When the voltage reaches 6.3 volts the 744T will power down—any recordings in-process will automatically stop.
External Powering
The 744T can be powered from clean DC power sources within a range of 10–18 VDC, 12 watts minimum. Connection to the 744T is through the 4-pin Hirose connector (Part # HR10-7P4P). Pin-1 of the connector is negative (−) and pin-4 is positive (+). Additionally, pin-2 (−) and pin-3 (+) are used to supply current to the charging circuitry for the removable Li-on cell.
Pin-1 and pin-2 of the external DC input are at the same ground potential as chassis ground and signal ground.
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