HP 8560A, Руководство по обслуживанию

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10 7 MHz
C A L O S C
i
D C
J 3
I
I
L I N E A R
I
I
I
L
I F A D J O F F
W 5 4
D I S C O N N E C T E D
LOG
I
I
W I T H C O U N T E R O N
i
B U R S T S O F 5 . 3 5 M H z
I
A P P R O X 1 0
w53
I J 5
I
( B
R O W N
)
w55
D E M O D
I
( W H I T E /
I
B L U E )
, A 4 L O G A M P / C A L O S C A S S E M B L Y
A
1 0 . 7
M H z
F A D J O F F
S K 1 7 1
Figure 8-2. IF Section Troubleshooting with TAM
Both the digital control and 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
are listed below:
Channel A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pin 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Channel C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pin 4 (MS4)
Channel D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 and monitor the output of
with a second spectrum analyzer.
IF Section 8-7