Tektronix 494AP service manual Maintenance- 494A1494ApServiceVot..t, 0xxx U302s, SwtTcH

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Processor Address Decoder _ Address decoder U3035on the processor board decodesseverd chip_

sel€cts. Y0, y5, y7

Y'1, and areshownin relationto the T/6-linein Figure6-37.

Itflull ----lMmoxxx

Ixxr

SXXX

IilMU- erxx

5565-75

Flgure 6-33. Four maln bloack select outputs ot address

decoder U20tf5.

Maintenance- 494A1494ApServiceVot..t

4XXX

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u3025,

I- PIN12

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Figure6-35. RAM select output in retationto-llXXX.

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0xxx

u302s,

PIN6

u3025,

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Figure 6-34. RAM select ouhut in relailon to dXXX.

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OPTIONS

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SELECT

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Figure6-36.-Ip and51050setecttinesIn relationto 0XXK

GPB Board Address Decoders Address decoderU1055on the GPIB board sets its outputslow to selectthe GPIA, the GPIB address switch and the banklatch. Y2, Y4, and YGare shownin relationto-TO in Figure6-38.

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6-53