Tektronix 494AP service manual O o o o o o o o o o o o o o o o o o o, Secton 4g4Al494ApServiceVol

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Secton 4 -

4g4Al494ApServiceVol. 1

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PERFORMANCE

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CHECK

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Introduction

Verification of Tolerance Values

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All performancechecks are carried out without

Compliance

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removing

tests,of thoselimitslistedin the p€rfor-

the instrumentcovers.

mance

Requirement column of

the

instrum€nt

The procedures

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specifications,

in this sectionverify

up timeand

shallbe perform€dafter sufficient

ment performancesatisli€s

that the instru-

comptetionof

preliminary

warm-

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the performancerequire-

pr€parationsteps

rnents specified under the performanceRequirement

(suchas front-paneladjustments).

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columnin Section2, Specification.

Measurement

Someparametersand

toleranceof test eguipment

instrumentfunctionsthat are

negligiblein comparison

shouldbe

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to the specifiedtolerance;and,

not explicitlyspecifiedare also checked.Thesechecks

when not

negligibte, the

error of

the

measuring

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verifythatthe

instrumentperformsas described.

apparatus

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shallbe addedto the tolerancespecified.

Checksshould be performedin sequencebecause

som€ tests rely on the satisfactoryperformanceof

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related circuits. Also, the cneck

iteps have been

History Information

arrangedso that the changing

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of test equipment

setups

from one stepto the next is minimized.

The

instrument and

manual

are

periodically

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lf a measurementis marginalor belowspecification,

evaluated and updated.

lf

modifications require

changesin the procedures,

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an adjustmentprocedure

informationapplicable

earlierinstruments

to

to enhanceperformancewill

be

wil be includedwithin

found,undera similartreading,in Section5, Adjust-

sub-partto a step.

a stepor as a

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ment Procedure.After adjustment,

recheckthe perfor_

mance. Adjustonly thosecircuits

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formancecriteria.

that do not meet per-

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lf adjustmentfails to return the circuit to specified performance,refer to the Maintenancesection for troubleshootingand repairprocedures.

Incoming Inspection Test

The Operatorsmanual containsan operationalor functionalcheckthatchecksall functions.Thiseheckis recommendedfor incoming inspectionsbecause it requiresno externalequipmentor specialexpertiseand is a reliableindicationthat the instrumentis perforrning properly.

Option Instrument Checks

. Wheneverpractical,performancechecksfor option instrumentsare integratedin the performance

check steps for the standard instrument,otherwise special check-steps are provided under OPTION INSTRU- MENTStowardsthe backof thissection.

Equipment Required

Table 4-1 lists the test equipmentand calibration fixturesrecommendedfor the performance

Check, This equipmentis also applicablefor the adjustmentpro_ cedures in Section 5, Adjustmentprocedure. The equipmentcharacteristicsspecifiedare the minimum requiredfor the checks. Substituteequipmentmust meet or exceed these characteristics.These fixtures are availablefrom Tektronix,Inc., and may be ordered throughyour localTektronixFieldOfficeor representa- tive.

Some checks may not be practicalbecausethey may require sophisticatedtest equipmentand/or pro- cedur€s.In those cases,a compromisemay be made in the procedures. When that occurs,a statementor footnoteto that fact is addedto the step. The more

exact method of measuringthe characteristiccan be suppliedby yourTektronixServiceCenter.

4-1