HP 4395A - Page 228

INSPECT THE ACCESSORIES
Measurement problems can be caused by faulty accessories or faulty devices between the
accessories and the analyzer.For example, the RF cables, the probe power connector, the TEST
SET-I/O INTERCONNECT connector, and the interconnect cable can cause problems.
Some recommended accessories used with the analyzer are listed below.
Test Sets (for example, the HP 85046A/B S Parameter Test Set).
Active Probes (for example, the HP 41800A Active Probe).
Preamplier (for example, the HP 19855A Broadband Preamplier).
Power Splitter and Directional Bridges (for example, the HP 11850C/D Three-way Power
Splitter).
Calibration Kits (for example, the HP 85032B 50  Type-N Calibration Kit).
Inspect the cables for any damage.Verify the probe power connector and the TEST SET-I/O
INTERCONNECT connector (if they are used). Then inspect and verify the accessories that are
used in the measurement.
This inspection consists of the following procedures:
Verify the Probe Power
Inspect the Test Set
Inspect the Calibration Kit
Verify the Probe Power
Perform the following procedure to verify the front-panel probe power connector:
1. Turn the analyzer power o.
2. Remove the power cable of the accessory from the probe power connector
.
3. Turn the analyzer power on.
4. Measure the power voltages (+15 V and -12.6 V) at the probe power connector using a
voltmeter with a small probe. See Figure 9-1 for the voltages and pins on the probe power
connector.
If the voltages are within the limits, the analyzer's probe power is veried. Suspect a
faulty accessory.Verify the accessory used in the measurement problem in accordance
with its manual.
If the voltages are out of the limits, see the Power Supply Troubleshooting chapter in this
manual to troubleshoot the power lines (+15 V(AUX) and -12.6 V) of the probe power.
9-4 Accessories Troubleshooting