Instrument Cooling; Start-Up; Detailed Operating Information - Tektronix 2246 1Y Service Manual

Preparation For Use—2246 1Y and 2246 IVIod A Service
To verify the proper value of the power-input fuse
for the 2246 1Y or 2246 Mod A, use the following
procedure.
1. Disconnect the ac-pow er
instrument.
2. Press in the fuse-holder cap with a straight-
bladed screwdriver, then release it with a slight
counterclockwise rotation.
3. Pull cap (containing fuse) out of fuse holder.
4. Check that the fuse is of the type and rating as
specified on the rear panel.
5. If the installed fuse is not of the correct type and
rating, replace it with a proper fuse and reinstall
the fuse-holder cap.

INSTRUMENT COOLING

You must provide adequate airflow into the instru­
ment to prevent possible damage from overheated
components. Before turning on the power, make
sure that ventilation holes on the bottom and right
side of the cabinet are not blocked. After turning the
instrument on, check that air is being exhausted
from the right side ventilation holes.

START-UP

When the power is turned on, the instrument per­
forms a self-diagnostic routine. If the instrument
2 - 2
fails to come on and operate normally, the Trigger
MODE LEDs may be flashing to indicate the circuit
location of a start-up error. Also, under certain
conditions, the Tektronix Part Number of the device
source from the where the error exists may be displayed on the
screen. Refer to Troubleshooting in the Maintenance
section of this manual for an explanation of the
start-up error codes.
When the instrument is turned on, a self-cal routine
may
measurement constants. During normal operation,
the power-on self cal happens only if the stored
constants have been lost as the result of a dead
memory back-up battery. The instrument may be
used
accuracy by running the SELF CAL MEASUREMENTS
routine from the SERVICE MENU after the instrument
has warmed up for at least 20 minutes.
To run the SELF CAL MEASUREMENTS routine:
Press the top and bottom m enu-item select buttons.
Select INTERNAL SETTINGS MENU, then SELF CAL
MEASUREMENTS. Press RUN to start the routine,
then QUIT to return to the normal oscilloscope
mode.
For operating information for specific instrument
functions, refer to the 2246 1Y and 2246 Mod A
Operators Manual.
run to set the voltage-
with no reduction

DETAILED OPERATING INFORMATION

and tim ing-
in the measurement