Teardown, Repair and Analysis of an Anritsu MS2721B 7.1GHz Portable Spectrum Analyzer

In this episode Shahriar investigates the failure of an Anritsu MS2712B 1.7GHz portable spectrum analyzer with built-in tracking generator. The instrument is missing the main firmware flash card which is easily replaced. A full teardown of the instrument is presented with focus on both the tracking generator PCB and main RF deck. Various ASICs and microwave components are closely examined. To help with removing and replacing many microwave screws, a Hitachi/Metabo electric screwdriver is used which can be purchased here.

After re-assembly of the unit, it becomes apparent that a mechanical push on the RF deck causes the LO1 PLL to unlock. This points to a fault in one of the microwave components. The issue is traced to a broken solder joint inside of the VCO modules. After repair, the instrument functions normally. The performance and tracking generator functionality is verified by measuring a tuneable band-pass filter.

4 comments

  1. Piero says:

    Hi, I saw a video from November 2018 where you were fixing an Anritsu Spectrum Analyzer. I appreciated your ability to put your hands inside the hardware … I wouldn’t be able to. On my tool (Anritsu MS-2721B) I see an annoying freezing that is always periodic. I have checked everything that can be checked, I have performed various resets and I have also made several firmware upgrades … but the problem remains as it is. I thought that the CPU saved the measurement every 4 or 5 sec on the RAM and therefore overstrained the CPU, or a problem related to the gate sweep. But I have no means of making a thorough diagnosis. The device currently does not have a battery and is powered by its power supply.

    Really sorry, I don’t have the opportunity to show you a small video highlighting this singular problem.

    Thanks a lot for your help.

  2. Sam Reaves says:

    I have one of these units. I wish that there was a way to get the tracking generator to go below 400Mhz as it would be a really useful instrument.

    Does the GPS feature work on yours?

    I also have a Anritsu MS2626A that goes to 6.5Ghz with a TG that I believe covers the full frequency range but I have not had the chance to pop it open as it has issues and will not self cal. I have yet to find a manual for it. It would make a great tear down and repair video. It looks to be the same generation as the HP 8590 series. So if you or one of your subscribers happen to know about this instrument I would love to get it going.

    I really enjoy your in-depth videos.

    Sam
    W3OHM
    Owner/Moderator of groups.io LeCroyOwnersGroup

  3. Mazen says:

    Excellent

  4. Burt Weiner says:

    Great videos, both on the MS2721A and MS2721B.

    How can you be contacted?

    biwaUSA

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