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Proper operation of the detectors can be tested with the following sequence.
TRACE B
[
-
]
CLEAR
WRITE
Instrument Preset
[VIEW) TRACE B
[SHIFT) TRACE A m
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Negative Peak Detection
If the traces do not coincide in the above test, refer to "Track and Hold Adjustments" in the
Performance Tests and Adjustments Manual.
If the voltage on A3A9TP8 is correct and that of A3A9TP9 is incorrect when performing the
BIAS Check of Note 10 on the schematic, check to see if the drain and source voltages on Q14
are approximately +l V. If not, Q14 is most likely open.
The LTRK signal is verified using an oscilloscope. Following an Instrument Preset, set the
spectrum analyzer sweep time to 75 ms. Figure 5 shows the resultant waveform.
O s c i l l o s c o p e
s e t t i n g s :
S w e e p t i m e : 5 0 ms/div
A n o l y z e r S w e e p t i m e : 7 5 m s
The Decoding and Timing 0 is checked using an oscilloscope. Figure 6 shows the timing
waveforms when using Digital Storage Test Program 5. When Digital Storage Test Program
6 is used, HOLD is normally high. It goes low every 80 ms. The two reset lines are then
active only every 80 ms. Figure 5 shows the LTRK line for a sweep time of 75 ms following an
Instrument Preset.
Figure 5. LTRK Timing Waveform
(both traces coincide)
(both traces coincide)
I
I
I
5
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