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6-11. x10Q Amplifier Test
This test checks the circuits in the signal path shown in Figure 6-3. If the previous tests have
been performed, the only untested circuit in this path is the xlOO Amplifier. Three ad
justments must be made to the xlOO Amplifier: the low frequency input impedance, the gain,
and the dc-offset of its output. Initially, the scope and the -hp- 3325A opt 001 are connected
to the 0-40MHz Input. The input signal is displayed on the scope, and the input impedance is
adjusted until the correct amplitude is obtained. The output signal is then displayed and the
gain is adjusted to obtain the correct amplitude. Finally, the output is measured with an -hp-
3455A voltmeter and the dc-offset is adjusted for zero volts. The program allows the user to
cycle through these procedures repeatedly to ensure proper adjustment.
Initializing the x100 Amplifier Test
With the High Frequency Menu displayed, press SFK K3 to initialize the test. After in
itialization, follow the instructions displayed on the computer.
What if the Test Fails?
Assuming that the previous test has passed, and that the equipment is properly connected,
the xlOO Amplifier, relay Kl 1, or K14 is probably at fault. Refer to Service Group Two for a
schematic, component locator, and circuit description for the 40dB Amplifier. The
"SWITCH" subprogram may be useful in troubleshooting this circuit.
Equipment Set Up
A4R51 Adjustment
1 3325
SIGNAL
< j j >
r~|
o
35601
o O
^ ^
i
j
0-40 MHZ
50Q
INPUT
OSCILLOSCOPE
CHA
O
c~
EXT
I B TRIG
T
1
NOTE: Turn off -hp-3455A for adjustment of A4R51.
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