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A3 Assembly Control Circuits
A digital control problem will cause the following three steps to fail.
1. On the spectrum analyzer, press
(i$Kii%Z),
ATTEN
MAN,
7, 0, and (dB.
2. A click should be heard after pressing dB in step 1, unless
ATTEN
was previously set to
70
dB.
3. Press 1, 0, and
(dB.
Another click should be heard. If no clicks were heard, but the
ATTEN
value displayed on the CRT changed, the digital control signals are not operating
properly.
Analog
Bus
Drivers
Refer to function block N of A3 Interface Assembly Schematic Diagram in the
HP 8560 E-Series Spectrum Analyzer Component Level Information.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Press
(“1
on the spectrum analyzer, and set the controls as follows:
Span
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
Trigger
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single
Monitor A3U401 pin 3 (LRF-STB) with
an oscilloscope or logic probe. This is the
for the Al5 RF Assembly.
strobe
Press
(mCTRL)
and
REAR
PANEL and check that pulses occur when toggling between
10
MHz
1NT
and
10
MHz
EXT.
Monitor
U401
pin 5
(LFCSTB)
with an oscilloscope or logic probe. This is the strobe for
the Al4 frequency control assembly.
Press
(AMPLITUDE)
and check that pulses occur when toggling between
ATTEN
settings of
10 and 20 dB.
Monitor
U401
pin 7 (LIF-STB) with
an oscilloscope or logic probe. This is the strobe for
the A5 IF assembly.
Press
(-1
and check that pulses occur when toggling between REF LVL settings of
-10
dBm
and -20
dBm.
Monitor
U401
pin 9 (LLOG-STB) with an oscilloscope or logic probe. This is the strobe
for the log amplifier on the A4 assembly.
Press
(-1
and check that pulses occur when toggling between
LTNEAE
and
Lac
~B/~)IV.
To check the Address and Data Lines, place a jumper from
A3TPl
and
A3TP2
to
A3U406 pin 20
(+5
V).
Check that address lines
A0
through A7 and data lines DO through D7 are all TTL high.
If any address or data line is low, press (LINE) to turn spectrum analyzer off and disconnect
the W2 control cable from
A3J2.
Press (LINE) to turn spectrum analyzer on. Ignore any
error messages.
8-28
ADC/lnterface
Section