Tektronix CURVE-TRACER 576 Instruction Manual page 161

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Type 576
SECTION 1
ADJUSTMENT PROCEDURE
General
The following procedure is arranged to allow a complete
or partial adjustment of all the internal controls in the Type
576. Most of the steps require the use of only the calibra-
tion fixture and a precision DC voltmeter. After becoming
familiar with the procedure, a calibrator can easily adjust
the Type 576 in an on-line situation by leaving out some
steps such as checking power supply regulation (step 3) and
adjusting the horizontal compensation (step 11).
Maintenance
Any maintenance required on the Type 576 should be
completed before starting this procedure. If troubles occur
in the middle of the procedure, they should be corrected
before proceeding. Repair and servicing information is given
in the Maintenance section.
Equipment List
The following equipment list gives the equipment
required to use the following procedure. The required
ranges and tolerances of this equipment along with some
suggested instrument types are also provided. To allow
accurate measurement, the required tolerances given for
each piece of equipment have been chosen to exceed the
tolerance to be measured by at least 4 times. For tolerances
to be measured to less than 1%, the accuracy of the equip-
ment has been chosen to exceed the tolerance by at least 10
times.
1. Type 576 Calibration Fixture (Tektronix Part No.
067-0599-00).
2. DC Voltmeter (e.g., Fluke Model 801 B differential
voltmeter or suitable digital voltmeter). Requirements:
Voltage range from 0 volts to ±250 volts, basic accuracy
within 0.5%, accuracy within 0.05% between 0 and ±75
volts.
1
3. DC Voltmeter-High Voltage (e.g., Triplett Model
630 NA). Requirements: Measure -4000 volts, accuracy
within 3%.
1
A similar DC voltmeter, but with very high input impedance (500
Mnl
is required for the performance check. Although this high an
input impedance is not required for the adjustment procedure, it
may be desirable to use the same instrument for both procedures.
ADD AUG 1984
4. Test oscilloscope examples are: Tektronix 2200 series
or 5100 series. Requirements: Bandwidth from DC to 200kHz,
sweep rates from 0.2 ms/cm to 5 !LS/cm, vertical deflection fac-
tors from 10 mV/div to 2 V/div, accuracy of voltage measure-
ment within 3%, AC vertical input coupling, internal triggering,
X1 test probe.
5. Variable autotransformer (e.g., General Radio,
Variac Type W10MT3W for 115-volt operation, or Type
W20HMT3A for 230-volt operation). Requirements: Out-
put voltage variable from 90 V to 136 V AC RMS for
115-volt operation or from 180 V to 272 V AC RMS for
230-volt operation; maximum power output at least 305
watts. If a monitor voltmeter is not included, a separate AC
voltmeter is required.
6. NPN transistor with BVcEO of 50 volts or more.
Record and Index
Table 1-1 at the beginning of this procedure provides a
record and index of the procedure. The table may be used
as a check list to verify adjustments, an abridged guide for
an experienced calibrator, or an index of individual adjust-
ments. Note that each listing of an adjustment also includes
a list of related adjustments or checks.
Control Settings
A complete list of initial control settings for the Type
576 and significant control settings for the test instruments
precedes step 1 of this procedure. In addition, partial lists
of control settings are provided in various places through-
out the procedure. Any control setting not listed in a
partial list should be set as designated in the initial list of
control settings. If adjustments are made without following
the procedure, start with the list of control settings
preceding the desired adjustment and follow the sequence
up to the desired step, making changes in control settings as
indicated.
Making Adjustments
When doing a complete adjustment of the instrument
each internal control should be adjusted as near to
th~
specified setting as possible, even if the observed perfor-
mance is within tolerance. When doing only a partial adjust-
ment, do not readjust any controls unless the observed
performance is outside the given tolerance. In either case,
do not preset any adjustments unless they are known to be
significantly out of adjustment or repairs have been made in
the circuit. In these instances, set the particular controls to
midrange.
A-3