HP 83522A Service Notes page 251

Model 83522A
Service
Open relay IS2 by entering on the 8350A:
M2
dBm
dB
0
Hex Data Write E8
Relay K2 should now be open. Verify that the level of the signals at TP3 and TP4
is less than previously noted.
Analog Switches U3D and U11. The analog switches are checked by using
the Hex Data Write feature of the 8350A to control the switches. A known FM
input is applied and switch operation is verified.
Connect equipment as shown in Figure 8-41. Adjust the function generator for a
500 Hz 1V peak-to-peak sine wave output.
On the 83504 enter:
SHIFT 0
0
2
G H z s
0 4
M2
dBm dB 8
Enters the Hex Data command
Address location 2C04 (U16)
Hex Data Write E8
Analog switch U3D should be closed. Verify that there is a signal at TP3.
On the 83504 enter:
M2 dBm
dB 0 Hex Data Write E O
Analog switch U3D should be open. Verify that there is no signal at TP3.
On the 8350A, enter:
M2 dBm
dB
8
Hex Data Write E8
Analog switch U11 should be set to the zero position. Verify that a signal is
present at TP6.
On the 83504 enter:
M2 dBrn dB GHz s
Hex Data Write EC
Analog switch U11 should be set to the one position. Verify that no signal is
present at TP6.
Power Sweep/ALC Adjustments Troubleshooting
The most likely indication of a failure in these circuits is either incorrect or no
operation of the Power Sweep function or inability to adjust the output power
flatness. The Power Sweep DAC U17 is exercised by initiating the Power Sweep
DAC self test, and the DAC output is checked at TP8. On the 83504 enter:
SHIFT
5
1 Initiate Power Sweep DAC Self
Test
Verify the waveform at TP8 corresponds with the waveform in Figure 8-38.
8-49