Troubleshooting; Isolating A Malfunction - Agilent Technologies 11713A Operating And Service Manual

Troubleshooting

Isolating a Malfunction

Use the following procedure to help you isolate a malfunction.
Recommended test equipment for troubleshooting is listed in Table
4-1.
Figure 8-2 and Figure 8-3 identify the assemblies and test points
specified in the steps below.
Procedure
1. Remove the switch driver top cover. Refer to "Module Cover
Removal/Replacement".
2. Turn on the driver and verify that the proper power up status is
reached. The driver should come up in local with all pushbutton
LEDs on, which corresponds to the maximum attenuation settings.
3. Measure the voltages at A1TP1 and A1TP2
TP1 = + 5.0 ± 0.5 Vdc
TP2 = + 24.0 ± 1.0 Vdc
4. Verify that the + 24.0 ± 1.0 Vdc is present at the rear panel red
banana jack.
5. If an attenuator or switch buzzes when actuated by the front panel
pushbutton, the output transistor may be shorted, or one of the
protection diodes may be shorted.
6. If one of the pushbutton LEDs does not light, determine if the
pushbutton is operational by checking to see if the circuitry drives
an attenuator or switch properly. If the switching click of the relay in
the attenuator or switch can be heard, only the LED may be
defective.
7. Check the driver in full local operation before testing in remote
operation.
If a pushbutton does not actuate an attenuator section or change the
position of a coaxial switch, do the following:
a. Check the output pulses of the A7 switch board assembly either
at the A7 outputs or on the multiplexer inputs of the A4 remote
local logic assembly.
b. If the pulses are present when the corresponding front panel
button is pushed, check the output of the A4 multiplexers. Verify
that the multiplexers are in local mode of operation.
Servicing the Attenuator/Switch Driver
11713A Operating and Service Manual 8-5
Troubleshooting