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20. 50 MHz Voltage-Tuned Oscillator Adjustments
14. Adjust All POS SUPPLY
AllR6
for a DVM indication the same as
that noted in step 12. See Figure 3-79 for location of adjustment.
VT0
High-Frequency
15.
Key in LSHIFT)
(CF
STEP SIZE]
J
112
kHz and
Cm)
I-1
N.
End Adjustment
16. Adjust All OFFSET
AllRlO
for VTP frequency indication 28.000
MHz
f0.005
MHz.
17.
Key in
ISHIFT)
[CF
STEP SIZE)
J
12
kHz and
[SHIFT)
I-1
N.
18. Adjust All GAIN
AllR9
for VT0 frequency indication of 28.750
MHz
fO.005
MHz.
19. Repeat steps 15 through 18 until specifications of steps 16 and 18
are achieved.
VT0
Low-Frequency
20. Key in
ISHIFT)
[CF
STEP SIZE]
J
912
kHz
(m)
[wCF_)
N.
End Adjustment
21. Adjust All SHAPING ATTN
AllR42
for VT0 indication of 22.000
MHz
f0.005
MHz. See Figure 3-78 for location of adjustment.
22. Key in
(Ml
(CF
STEP SIZE)
J
1012
kHz and
[SH’FT)
[NII(R)
N.
23. Adjust All SHAPING OFFSET
AllR17
for VT0 frequency
indication of 21.250 MHz
*0.005
MHz. See Figure 3-78 for
location of adjustment.
24. Repeat steps 21 through 23 until specifications of steps 20 and 23
are achieved.
25. Go back to step 15 and repeat both High-Frequency End and
Lo-Frequency End adjustments until specifications of both
(contained in steps 16, 18, 21, and 23 are achieved.
VT0
26. Key in
($KEj
[CF
STEP SIZE)
J
512 kHz and
Cm)
[m)
N.
Center-Frequency
27. VT0 frequency indication should be 25.00 MHz
f0.02
MHz. If
Checks
it is not, and specifications of steps 16, 18, 21, and 23 are met,
a malfunction is indicated. The most likely suspects would be
varactor diodes
CR15
and
CR16.
28. Key in
ISHIFT_)
[CF
STEP SIZE]
J
612 kHz and
cm]
I-1
N.
29. VT0 frequency indication should be 24.25 MHz
kO.02
MHz. If
it is not, and specifications of steps 16, 18, 21, and 23 are met,
a malfunction is indicated. The most likely suspects would be
varactor diodes
CR15
and
CR16.
30. Set LINE switch to STANDBY.
31. Replace Al1 50 MHz Voltage-Tuned Oscillator in instrument
without extenders and replace screws in cover.
3-132 Adjustments