Note

When

measuring voltages or waveforms, make ground connections to A2TP3.

 

The metal board-standoffs are not grounded and should not be used when

 

taking

measurements.

 

 

 

Troubleshooting Using the TAM

Refer to Chapter 7, “General Troubleshooting,” for information on enabling the TAM for use with the HP 85623 Spectrum Analyzer.

Table 10-l lists assembly test connectors associated with each Manual Probe Troubleshooting test. Figure 10-l illustrates the location of the A2 test connectors.

Table 10-l. TAM Tests versus Test Connectors

IConnector

A2Jll

Manual Probe Troubleshooting Test Measured Sienal Lines

 

ADC/MUX Test

MSl, MS3 through MS6, MS8

 

DAC test

 

MS2. MS7. OS1

 

10

volt

reference test

MS4

 

Switch

drive test

MS8

 

Buffered X & Y DAC outputs

MS2, MS7

 

X line gen test

MS6

 

Y line gen test

MS1

 

Intensity

offset output

MS3

 

Revision

 

MS1

 

X, Y, & Z Output Offset

MS3, MS4, MS7

 

X

output

amplifier

MS7

 

Y

output

amplifier

MS3

 

Blanking

test

MS8

 

Focus DAC test

MS2

 

Blank Display

Use the following procedure if the instrument display is blank. This procedure substitutes an HP-IB printer for the display.

1.Connect the printer to the spectrum analyzer and set the printer address to the value required by the TAM. This is usually 1.

2.All of the power-supply indicator LEDs along the edge of the A2 controller assembly should be lit.

3.The rear-panel CRT fll0 VDC ON indicator might not be lit, even if the -t-110 V is present.

4.Connect the TAM probe cable to A2Jll.

5.Press (-1, SDFT KEY #3, a, SQFT FFY #I . (The top softkey is #l.)

6.The yellow LED next to A2Jll should blink approximately ten times. If the LED fails to blink correctly, troubleshoot the digital section of the A2 controller assembly.

1 O-2 Controller Section

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Agilent Technologies 856290216 service manual MSl, MS3 through MS6, MS8, Controller Section