Power Sweep Not Functioning Properly; No Power Output - HP 8560E Service Manual

The 600 MHz drive signal should be -8 dBm ±3.5 dB. The 1st LO signal
NOTE
should be +16 dBm ±2 dB.

Power Sweep Not Functioning Properly

Power sweep is accomplished by stepping real time DAC #1 (R/T DAC1)
which adds an offset to the POWER LVL signal. Refer to Function
Block S of the A14 frequency control assembly schematic. R/T DAC1 is
an 8-bit DAC and can provide power sweeps of up to 12.8 dB. This is
equivalent to 0.05 dB per DAC step. Since R/T DAC1 has only 256
discrete settings but 601 points per sweep are digitized, up to three
adjacent points per sweep may correspond to the same power level
setting.
1. If the power sweep appears to be non-monotonic, the fault probably
Although power sweep range may be set to a 12.8 dB sweep width, the
NOTE
power sweep function is only warranted to have a 10 dB sweep width.
2. Perform the "Vernier Accuracy" performance test. If this test fails,

No Power Output

The A10 requires power supplies, a 1st LO signal, and a 600 MHz drive
signal in order to provide power output.
1. Check power supplies on A14J13 and A10J1. Refer to the A14
2. Verify that the voltage at A14J17 pin 14 is greater than +14 Vdc. If
Chapter 11
frequency. A 1 MHz sideband on the 1st LO will appear as a 1 MHz
sideband on the output signal.
To verify that the 600 MHz drive or 1st LO signal is responsible for
the sidebands, substitute a clean signal for the 600 MHz drive or 1st
LO signal. If the sidebands on the output disappear when using the
clean signal, the substituted signal was responsible for the
sidebands.
lies on the A3 interface assembly (real time DACs). To check the
operation of R/T DAC1, monitor A3J400 pin 3 with an oscilloscope.
Trigger the oscilloscope off the negative-going edge of the
BLKG/GATE OUTPUT (rear panel) of the HP 8560E/EC. Set the
power sweep range to 12.8 dB and tracking generator RF POWER to
−10 dBm. Set the HP 8560E/EC SWEEPTIME to 50 ms. A 0 to +10
V ramp should be observed on the oscilloscope. The amplitude of the
ramp should decrease approximately 780 mV for each 1 dB decrease
in power sweep range.
refer to "Vernier Accuracy Out-of-Tolerance" in this chapter.
frequency control assembly schematic.
the voltage is not greater than +14 Vdc, troubleshoot A14.
RF Section
A10 Tracking Generator (Option 002)
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