What to do if 'POWER ON TEST FAILED' appears on HP 4395A Test Equipment?
- JJuan TaylorAug 7, 2025
If the 'POWER ON TEST FAILED' error message appears on the LCD of your HP Test Equipment, execute all internal tests to identify the first failed test.

What to do if 'POWER ON TEST FAILED' appears on HP 4395A Test Equipment?
If the 'POWER ON TEST FAILED' error message appears on the LCD of your HP Test Equipment, execute all internal tests to identify the first failed test.
Why is the A50 SHUTDOWN LED off on my HP Test Equipment?
If the A50 SHUTDOWN LED is off, some of the A50 power supply is shut down by the A50 shutdown circuitry. The only way to reset the circuit is to turn the HP Test Equipment power off, wait a minute, and then turn it back on.
What to do if I get unexpected results after inspecting the fan in my HP Test Equipment?
If you encounter unexpected results during fan inspection of your HP Test Equipment, check the AC line power to the analyzer. Verify the fuse (rating listed on the rear panel) and the line voltage setting.
What does it mean if the voltage between A50J3 pin 1 and pin 6 is out of limits on HP Test Equipment?
If the voltage between the A50J3 pin 1 and pin 6 is out of limits, the A50 DC-DC Converter may be faulty. Replace the A50 DC-DC Converter in your HP Test Equipment.
Why is the +5 VD LED not on in my HP 4395A?
If the +5 VD LED is not illuminated, the +5 VD line voltage is either missing or insufficient to power the analyzer. Check the A40 pre-regulator in your HP Test Equipment.
| Frequency Range | 10 Hz to 500 MHz |
|---|---|
| Resolution | 1 Hz |
| Dynamic Range | > 100 dB |
| Impedance | 50 ohms |
| Measurement Functions | Impedance |
| Interface | GPIB |
| Dimensions | 426 mm |
Manual's introduction and purpose.
Describes the manual's structure and components.
Overview of performance test procedures.
Details Description, Specification, and Test Equipment.
Explains the purpose of calculation sheets.
Details calculation for Level Accuracy.
Explains the purpose of the performance test record.
Record sheet for Frequency Accuracy Test.
Overview of adjustments for the analyzer.
Highlights safety precautions during adjustments.
Explains the troubleshooting approach and organization.
Diagram showing troubleshooting flow.
Procedure for identifying power supply issues.
Initial steps for power supply troubleshooting.
Guide to troubleshooting the digital control group.
Procedure for replacing the A1 CPU assembly.
Troubleshooting common accessory issues.
Confirms correct operation of accessories and connections.
Information on ordering and identifying parts.
How to order parts using HP part numbers.
Procedures after replacing an assembly or EEPROM.
Lists procedures and verification steps for replaced parts.
Explains how to adapt the manual to earlier versions.
Lists manual changes based on serial number.
Guidance on selecting the correct fuse.
Specifies voltage, frequency, and power needs.
Lists and explains error messages alphabetically.
Lists and explains error messages numerically.
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