Tektronix 2246 1Y, Service Manual

Page: 96 / 433

Section 4—2246 1Y and 2246 Mod A Service
PERFORMANCE CHECK PROCEDURE
INTRODUCTION
PURPOSE
This Performance Check Procedure verifies the Perform­
ance Requirements of the 2246 1Y or 2246 Mod A as
listed in the Specification (Section 1) and helps deter­
mine the need for readjustment. These checks may also
be used as an acceptance test or as a preliminary
troubleshooting aid.
You do not have to remove the wrap-around cabinet from
the 2246 1Y or 2246 Mod A to do this procedure. All
checks can be made with controls and connectors ac­
cessible from the outside.
TEST EQUIPMENT REQUIRED
Table 4-1 lists ail the test equipment required to do the
Performance Check Procedure. Test equipment specifi­
cations described are the minimum necessary to pro­
vide accurate results. For test equipment operating infor­
mation, refer to the appropriate test equipment instruc­
tion manual.
When you use equipment other than that recommended,
you may have to make some changes to the test setups.
If the exact example equipment in Table 4-1 is not avail­
able, use the Minimum Specification column to deter­
mine if any other available test equipment might be ade­
quate to do the check.
PERFORMANCE CHECK INTERVAL
To ensure instrument accuracy, check the performance
of the 2246 1Y or 2246 Mod A after every 2000 hours of
operation, or once each year if used infrequently. If the
checks indicate a need for readjustment or repair, refer
the instrument to a qualified service person.
N O T E
The silver-oxide batteries used in the 2246 1Y
(instruments serial numbered B714999 and
below) MUST BE REPLACED AT LEAST
EVERY 12 MONTHS to ensure proper opera­
tion of the instrument.
PREPARATION
This procedure is divided into subsections to let you
check individual sections of the instrument when it is not
necessary to do the complete Performance Check. An
Equipment Required block at the beginning of each sub­
section lists the equipment from Table 4-1 that is needed
to do the checks in that subsection.
The initial front-panel control settings at the beginning of
each subsection prepare the instrument for the first step
of the subsection. Do each of the steps in a subsection
completely and in order to ensure the correct control set­
tings for steps that follow. To ensure performance ac­
curacies stated in the Specification (Section 1), let the in­
strument warm up for 20 minutes and run the SELF CAL
MEASUREMENTS routine.
To run the SELF CAL MEASUREMENTS routine:
Press the top and bottom menu-item select buttons to
display the SERVICE MENU. Underline and select SELF
CAL MEASUREMENTS. Press RUN to start the routine,
then QUIT to return to the normal oscilloscope mode.
N O T E
Performance accuracies are ensured only
when the SELF CAL MEASUREMENTS are
done AFTER the 20-m inute warmup.
REV OCT 1991
4-1