Agilent Technologies 856290216 service manual Video MUX, 16 ADC/lnterface Section

2.Disconnect W26 (coax 2) from A3JlOl and connect the output of a function generator to A3JlOl.

3.Set the function generator to the following settings:

Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Sinewave Amplitude . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 V pk-to-pk DC Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +500mV Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50Hz

4.Set the spectrum analyzer sweep time to 50 ms.

5.Adjust the function generator amplitude and offset until the sine wave fills the entire graticule area.

6.Measure and note the function generator peak-to-peak voltage using an oscilloscope.

v(10 dB/div) = V

7.Set the spectrum analyzer to 2 dB/div.

8.Readjust the function generator amplitude and offset until the sine wave again fills the entire graticule area.

9.Measure the function generator peak-to-peak voltage and dc offset.

v(2 dB/div) = V

10.The ratio of voltage recorded in step 6 to the voltage recorded in step 9 should be 5 f3%. If the ratio is not 5, troubleshoot the A3 Interface assembly.

11.Reconnect W26 to A3JlOl.

Video MUX

Refer to function block U of A3 Interface Assembly Schematic Diagram in the

HP 8560 E-Series Spectrum Analyzer Component Level Information.

1. Press [-ET) and set the spectrum analyzer controls as follows:

Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..300MHz Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz

2.Press [mSWP), (CAL), and IF &DJ OFF. Connect the CAL OUTPUT to the INPUT 50R connector.

3.Check for a TTL high on A3U104 pin 2 and a TTL low on U104 pin 10. Set the spectrum analyzer to 2 dB/div and check for a TTL high on A3U104 pin 10 and a TTL low on A3U104 pin 2.

4.If the logic levels on A3U104 are incorrect, check the LLOG-STB signal as follows:

a.Monitor A3U104 pin 9 with an oscilloscope or logic probe. Check that a 1 microsecond, low-going pulse is present when switching between 10 dB/div and 2 dB/div.

b.Check the inputs to A3U104 (pins 3 and 11) while switching between 10 dB/div and 2 dB/div.

8-16 ADC/lnterface Section