HP 8590A Spectrum Analyzer Attenuator Replacement Kit

Discussion in 'Ham Made Gear' started by WB9UFS, Dec 6, 2011.

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  1. WB9UFS

    WB9UFS Ham Member QRZ Page

    HP-8590A Attenuator Replacement Kit

    Maples Road Instrument Services
    9107 Maples Road
    Fort Wayne, IN 46816
    (LarrBeard@hughes.net )

    One of the most common failures of an HP 8590-series spectrum analyzer is destruction of one or more sections of the input attenuator due to excess power being applied to it, generally by inadvertently keying a transmitter into the input with insufficient attenuation between the transmitter and spectrum analyzer. If you’ve worked in RF engineering, you know the sinking feeling as you realize what you’ve just done – and the fleeting hope that you got away with it this time. (You know the test equipment lab guys are going to give you a hard time about this!)

    The HP 8590A Spectrum Analyzer uses a custom attenuator that is unavailable from either Agilent or the original manufacturer. This modification kit uses an HP OEM attenuator and an interface circuit card to replace the defective original attenuator. The old attenuator may be left in the instrument if desired. No soldering is required; the modification procedure requires disassembly of the HP-8590A and drilling two holes in the chassis to mount the replacement attenuator assembly. New SMA RF cable assembly and attenuator control cables are included.

    Step by step illustrated disassembly and reassembly procedures are provided on a CD-ROM as a Microsoft Word document. A hole template to correctly locate the two added holes is included as well as the required mounting hardware. Only common hand tools are required – but are not supplied.

    Each modification kit will be provided with a set of test data showing the performance of the individual kit. No refunds will be offered on this item. If a defective unit is suspected, contact me for assistance in troubleshooting and if needed, I will accept the unit for repair. NO refunds for “…I installed it and it didn’t fix the unit…”, or “… it looks too hard to install…”. If you have questions, contact me – let’s not have surprises for either one of us.

    (Suggested by my son-in-law, the lawyer)

    A. This modification kit was privately developed with no assistance from HP or Agilent. It is in no way endorsed by either of these companies. Use or mention of “HP”, “Agilent” or “HP 8590A” in no way conveys any endorsement or acknowledgement of this product by the original manufacturer of the unit or by its corporate successors

    B. This kit has been tested and verified as a replacement for a damaged input attenuator assembly. It has been extensively tested in four separate HP 8590A mainframes. An HP 8590A with no other defects will successfully complete its self-calibration routine with this replacement attenuator. This kit will not correct defects in the 1st Mixer caused by severe RF overload and damage to the mixer diodes or any other defects which may reside within the instrument.

    C. The HP OEM attenuators used in this kit are surplus commercial units. The attenuator modules are specified for 5-million operations. The attenuators appear to be new units, but I cannot guarantee that. I will warrant attenuator modules for 180 days for internal mechanical failures – NO WARRANTY FOR RF OVERLOAD!

    Cost for the modification kit is $225.00, free shipping. PayPal is preferred payment method.

    de WB9UFS

    ModKitAssy.JPG Mod Kit CCA.JPG
  2. KA5S

    KA5S Subscriber QRZ Page

    is this compatible with an 8590B? Don't need one (yet) but just in case, I've copied the message and pictures.

  3. WB9UFS

    WB9UFS Ham Member QRZ Page

    I've never seen inside an HP 8590B, so I'll have to ask some questions:

    A. Is the attenuator a 5-wire attenuator? Five wires= +15, 10 dB, 20 dB and 30 dB control lines and a ground. I have seen some attenuators with six wires, but I believe those are 75-ohm units with a preamplifier.

    B. Is there a vacant space between the display and the 2nd Mixer? As the 8590 series got more complex, empty space started to fill up.

    I'll do some searching to see if I can find some compatibility info.

    Thanks for asking. Pass the word around - there are a lot of those little analyzers out there that have been whacked.

    de WB9UFS
  4. WB9UFS

    WB9UFS Ham Member QRZ Page

    Well, I went looking.

    The HP-8590B was really a bigger step up than just a "Letter change". It was the first synthesized analyzer, so I suspect its innards are a lot different than the original A version. But - HP didn't change their front end architecture much.

    The 8590A used a Wavetek attenuator, HP P/N 0955-0329, which could have changed P/N's for any number of reasons. I erred in saying it had five wires - it's a 4-wire attenuator, HP didn't carry a ground in the cable, but I did for the replacement.

    I'd suggest you just look and see if there is a space to slip in a circuit card and attenuator about 1.5" x 3".

    That's my best shot.

    de WB9UFS
  5. KA5S

    KA5S Subscriber QRZ Page

    Thanks; I'll probably get "a round tuit" when I reset the counter. RSN!

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