Agilent Technologies 35670-90066 manual

Models: 35670-90066

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Agilent 35670A

Troubleshooting the Analyzer

 

To troubleshoot input and ADC failures

Step 2. Check the dc offset DAC.

Using the BNC-to-SMB cable, connect the oscilloscope to A1 P200 to check channel 1 or to A1 P700 to check channel 2.

G

If you changed the input signal or range, set the input signal to 2 Vp-p and the

range to 1 Vpk.

Set the oscilloscope to 700 mV/div.

Press the following keys:

[ System Utility ]

[ MORE ]

[ SERVICE TESTS ]

[ SPCL TEST MODES ]

 

[ MORE SPCL MODES ]

 

[ CHANNEL 1 SPCL MODE ] or [ CHANNEL 2 SPCL MODE ]

 

[ OFFSET DAC ]

 

0

 

[ ENTER ]

Note the dc offset voltage of the sine wave displayed on the oscilloscope.

Enter numbers between 127 and +128.

The sine wave dc offset voltage should change about 780 mV for a −127 entry and 780 mV for a +127 entry.

If the dc offset function is incorrect, the A1 Input assembly is probably faulty.

If the dc offset function is correct, the A5 Analog assembly is probably faulty.

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Page 229
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Agilent Technologies 35670-90066 manual