Table 1-3. Front Panel and Indicator Panel Controls and Indicators

TM11-7025-229-12

Front Panel and Indicator Panel Controls and Indicators. Table 1-3 lists and

describes front and indicator panel controls and indicators (fig. 1-1 and 1-2).

Item

Function

FRONT PANEL

PWR ON/PWR OFF Switch

Circuit-breaker power toggle switch. The

two-position power switch serves as the ac

power circuit breaker. It applies the 115V

ac to the unit and provides overload

protection by opening both sides of the ac

input lines when it trips.

ELAPSED TIME (Meter M1)

Numerical indicator. Shows the

accumulated time the disk unit has been

running (power application). Elapsed time

is shown in hundreds of hours, plus first

place decimal.

INDICATOR PANEL

PWR RDY Indicator

LED indicator. Indicates when ac power

has been applied to the disk unit and the

+ 5V logic voltage is being outputted from

the power supply to the control electronics.

OVER TEMP Indicator

LED indicator. Indicates an over-temp

condition in the HDA.

LED TEST Switch

Test toggle switch. Used to test the

functioning of the six LEDS.

SEL Indicator

LED indicator. Indicates that the disk unit

has been (UNIT SELECT) selected and

brought on line by the host computer.

RDY Indicator

LED indicator. Indicates that the units disk

drive is (UNIT SELECT) up to speed and

the read/write heads are positioned over

track zero (0).

UNIT SELECT Switch

Thumbwheel selector switch. Used to

assign a number (0-3), or address, to this

unit. This enables the host computer to

select this unit or any one of three

additional slave units that might be

connected to this unit.

1-7