If Section Troubleshooting With Tam - HP 8560A Service Manual

C A L O S C
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Both the digital control and DACs are multiplexed onto test point "channels" through
resistive networks. One DAC from each of the quad-DAC packages feeds into a network.
The TAM varies each DAC individually to isolate which ones failed. Similarly, 10
digitally-controlled lines feed into a network and are monitored by the TAM. The channels
used to monitor the DACs are listed below:
Channel A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A5J9 pin 1 (MSl)
Channel C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A5J9 pin 4 (MS4)
Channel D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A5J9 pin 2 (MS2)
1. On the spectrum analyzer, enter the TAM Cal Osc Troubleshooting Mode by selecting
diagnose then Cal Osc Troubleshooting Mode.
2. On the spectrum analyzer, disconnect W27 ( coax 3) from A5J5 and monitor the output of
10 7 MHz
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Figure 8-2. IF Section Troubleshooting with TAM
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B U R S T S O F 5 . 3 5 M H z
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A P P R O X 1 0 mSEC
w53
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IF Section 8-7