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8. 21.4 MHz Bandwidth Filter Adjustments
3-82 Adjustments
45.
Adjust A4ABR40 XTAL to align markers on display. MARKER
A level should indicate 1.00 X. See Figure 3-44 for location of
adjustment.
Dip Adjustments
46.
Refer to the Resolution Bandwidth Switching Uncertainty
Performance Test, and check all bandwidth amplitudes. If
amplitude of 300 kHz bandwidth is low but amplitude of 100 kHz
and 1 MHz bandwidths are within tolerance, LC DIP adjustments
must be performed. If all bandwidth amplitudes are within
tolerance, do not perform the following adjustments.
Set LINE switch to STANDBY.
4 7 .
48.
Disconnect cable 97 (white/violet) from A4ABJl and connect to
49.
Remove A4A4 Bandwidth Filter and install
50.
Set LINE switch to ON. Press
51.
Key in
[
CENTER FREQUENCY
1 MHz, [ATTEN) 0 dB, and LOG
]
SPAN
Short A4A4TP3 to ground.
52.
53.
Adjust. A4A4C41 LC DIP for minimum amplitude of signal peak.
See Figure 3-41 for location of adjustment. Key in
MARKER Ln], and adjust LC DIP again to offset the signal peak
approximately -17 kHz (to the left). This is done to compensate
for the effect of placing the board on extenders. If unable to
achieve a "dip" in signal amplitude, increase or decrease value of
Remove short, from A4A4TP3 and short A4A4TP8 to ground.
54.
Adjust A4A4C43 LC DIP for minimum amplitude of signal peak.
55.
See Figure 3-41 for location of adjustment. Key in
MARKER In], and adjust C43 LC DIP again to offset the signal
peak approximately -17 kHz (to
"dip" in signal amplitude, increase or decrease value of A4A4R60.
Refer to lhble 3-3 for range of values.
Set LINE switch to STANDBY.
56.
Reinstall A4A4 Bandwidth Filter without extenders.
57.
Short A4A4TP3 and A4A4TP8 to ground. Remove A4A8
Attenuator-Bandwidth Filter and install on extenders. Reconnect
cable 97 to A4ABJl and reconnect cable 89 to A4A6Jl.
Set, LINE switch to ON. Press
58.
Key in
59.
[
CENTER FREQUENCY
1 MHz, [ATTEN] 0 dB, and LOG
(
)
FREQUENCY SPAN
60.
Short A4ABTP6 to ground.
61.
Adjust A4ABC66 LC DIP for minimum amplitude of signal peak.
See Figure 3-43 for location of adjustment. Key in
MARKER @, and adjust LC DIP again to offset the signal peak
on
).
PRESET
20 MHz, [RES] 100 kHz,
]
left). If unable to achieve a
the
).
PRESET
20 MHz, CRES] 100 kHz,
)
extenders.
2
(
ENTER
)
SEARCH
[
)
PEAK SEARCH
(
ENTER
)
SEARCH
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