Tektronix 494AP service manual 1R1020, A46A1Rl015 446A1Rl010, Selectedcomponents

Models: 494AP 494A

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Malntenance- 494A1494ApService Vot. 1

tNumber

422A1Rl070

422A1R2049

422A1R2070

422A1R2072

A46A1R1011 1 R l 0 1 2

446A1Rl013

446A1Rl014

A46A1Rl015

446A1Rl010

1R1020

446A1Rl048

Rl049

446A1R1050

1 R l

A46A1Rl052

A46A1Rl053

A46A1Rl055

Table 6-4

SELECTEDCOMPONENTS

Selection Crlteria

SetsReferenceMixer outputat 18 MHz

linearityof the 2nd LO sweep Adjusts2nd LO tune range Sets2nd LO sweep

Matchedfor temperaturecoefficientto 5PPM/oC

Matchedfor temperaturecoefficientto SPPM/"C

Match€d for t€mperature coefficientto SPPM/oC

Matched for temperature coefiicient to SPPMI"C

Matchedfor temperaturecoefiicientto SPPM/"C

Matchedfor temperaturecoefficientto SPPM/oC

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45045C1038

 

 

450A5C1048

 

 

450A2C1016

3.3 pF-27

pF

A50A2C1018

3.3 pF-27 pF

A50A2C1032

3.3 pF-27

pF

450A2C1024

 

 

Surface-Mounted Components

Surface-mountedcomponents are used in this instrument.These componentsare mountedon pads on the circuit board, rather than through holes in the board. (ln some rare instances,componentsmay be mount€d on pads around through holes.) Lead configurationsof thesecomponentsare shownin Figure 6-1.

MoveC1041frequencyadjustmentrange

MoveCl042 frequencyadjustmentrange

FL1024inputloutputimpedancematch

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TRATT3IION

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The positive end of electrolytic capacitors is identifiedwith a band. Other capacitorsand resistors have no visibleidentification.However,like their axial- leadedcounterparts,their valuescan be measuredwith a meter.

Surface-mountedsemiconductordevicesare sensi- tive to static €lectricity discharges, and should be treatedas outlinedin the beginningof this section.

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Figure6-1. Surface-mountedcomponentslead conliguration.

6-16

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Tektronix 494AP service manual 1R1020, A46A1Rl015 446A1Rl010, Selectedcomponents