Hi,
I have a HP8596E spectrum analyzer with the following troubleshooting:
- Input level: CAL OUT (300 MHz, -20 dBm)
- When switching the input attenuator on all its _even_ positions (-20, -40 and -60 dB), the measured level is correct (-20 dBm). Just the noise floor level is increasing, which is normal.
- When switching the input attenuator on all its _odd_ positions (-10, -30, -50 and -70 dB), the measured level is wrong (about -15 to -20 dB), but only during 10 to 15 seconds. After this delay of time, the level increases slowly and becomes correct again.
Does somebody have an idea about this behavior and how to cure that?
I would appreciate some hints.
Regards
Dominique
I have a HP8596E spectrum analyzer with the following troubleshooting:
- Input level: CAL OUT (300 MHz, -20 dBm)
- When switching the input attenuator on all its _even_ positions (-20, -40 and -60 dB), the measured level is correct (-20 dBm). Just the noise floor level is increasing, which is normal.
- When switching the input attenuator on all its _odd_ positions (-10, -30, -50 and -70 dB), the measured level is wrong (about -15 to -20 dB), but only during 10 to 15 seconds. After this delay of time, the level increases slowly and becomes correct again.
Does somebody have an idea about this behavior and how to cure that?
I would appreciate some hints.
Regards
Dominique
There are (3) internal pad sections inside the input attenuator that make up a total of 70 dB of input attenuation; a 10 dB section, 20 dB section and 40 dB section. To achieve 30 dB of input attenuation for example, the 20 dB and 10 dB sections are switched in. Since the 20 dB, 40 dB and 60 dB settings appear to be operating correctly, it appears the 10 dB section is defective because every time that is switched in, there is an amplitude problem.
The input attenuator part number (33321-60037) is no longer available as the product is several years beyond the support life. Lower level parts such as the 10 dB circuit, contacts, etc. are still sold by Agilent. If you’re willing to open up the input attenuator, you may be able to find out which part is defective. This may be challenging as there are no schematic diagrams for the input attenuator itself. 99% of the time the switch logic is correct and the cause of the problem is the hardware itself. When the 10 dB section has a problem it is usually indicative of an over power situation. Perhaps visual damage can be seen and appropriate lower level parts can be ordered and replaced.
Regards -