Seagate STT8000A manual Mechanics, Cartridge load mechanism, Capstan drive motor assembly, Chassis

Chapter 7 Theory of operations

The following table shows clock frequencies used by the STT8000 drive

VCO Frequencies—All Derived from System Clock (42 MHz Crystal Oscillator)

Fundamental	28 MHz	28 MHz	28 MHz	24.89 MHz
Frequency
Channel	9.33 MHz	7.00 MHz	4.667 MHz	3.11 MHz
Frequency

Mechanics

The mechanical package for the STT8000 ATAPI minicartridge drive was designed to provide all the advantages of easy cartridge loading and unloading while maintaining the positioning accuracy necessary for high-density data recording. The orientation of the cartridge is the same as the majority of QIC minicartridge drives in the field.

Cartridge load mechanism

The cartridge is inserted in the drive by sliding it through the aperture in the bezel and into a tray mechanism. When fully inserted the back portion of the cartridge protrudes about 3/4-inch from the aperture. A switch is actuated at this point that causes a microprocessor to complete the loading operation.

When the tape is in motion, the amber LED on the front panel flashes. The LED is not lit when the tape is positioned at BOT.

Capstan drive motor assembly

In the STT8000 ATAPI minicartridge drive, the cartridge is driven by the capstan/belt motor assembly, which is on a linear slide. The cartridge is loaded against the cartridge drive roller which exerts a net radial dynamic force of 18 to 26 ounces. The motor is a brushless DC drive motor with integral capstan which is designed to provide maximum reliability.

The motor operates from the 12V nominal supply and moves the tape at speeds from 35 to 100 inches per second (IPS).

Chassis

The drive mechanism is mounted in a molded frame that provides the mounting holes for the industry standard 3.5-inch by one inch form factor. A 5.25-inch mounting kit is an available option. The bezel is a simple snap-on design that is available in several standard and custom colors. The round, front-panel LED is amber and indicates tape activity.

Page 70 STT8000A Product Manual