Synthesizer Section; Al4 Frequency Control Assembly; A7 Loda Drive - HP 8560A Service Manual

Al4 Frequency Control Assembly

Note The block diagrams for the Al4 and Al5 assemblies are located in Chapter 10,

Synthesizer Section.

A7 LODA Drive

See function block Z of Al4 Frequency Control Schematic Diagram (sheet 3 of 5) in the
Component-Level Information binder.
1. Set the HP 8560A to the following settings:
CENTER FREQ
SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...2 MHz
TRIGGER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..SINGLE
2. Measure the signal power at the output of A7 (see item (1) of Figure 11-2).
3. If the output power is low, A14U424A's output voltage, item (a), (A14J18 pin 14) should
be above 0 V. If the output power is high, the voltage should be more negative than
-10 V. If the voltages do not measure as indicated, check that the voltages at A14J18 pins
5 and 13, item (4), are consistent with the operational amplifier's output.
If a TAM is available, use Manual Probe Troubleshooting to make
Note
measurements on A14J18 pins 5, 13, and 14. These voltages are referred to as
. AMP CNTL, LO SENSE, and PIN ATTEN respectively.
4. If the voltages measure as indicated in step 3, measure the All YTO output. (See item (3)
of Figure 11-2.)
5. If all measurements are within limits, refer to "A7 LODA (LO Distribution Amplifier)" in
this chapter.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300 MHz
RF Section 1 l-9