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8590B no calibration after memory loss

Question asked by EremitaAnalogico on Nov 6, 2019
Latest reply on Nov 15, 2019 by Tardz

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Hi, I have at work one 8590B that has suffer of boring problem of backup battery dead.

I have replaced the battery (both lithium and supercap) and I tryed to recalibrate the instrument.

When I performed early attempts, the 8590 says that not found the calibration signal.

In effect it was displayed with a considerable offset.

I have tryed a -37Hz procedure, and with this both amplitude and frequency calibration starts, but the process end with span sens fail.

The display obtained is strange, I show it in attachment.

Naturally, these errors don't manifestate prior to battery fail.

I hope that someone can help me to restore this analyzer, thanks in advance.

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9 Replies

Tardz Nov 11, 2019 9:10 AM
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Hi,

You lost the calibration constants because of the faulty battery. I would first try to recall the default calibration constants.

First, enter the PASSCODE
FREQUENCY
- 37 HZ
CAL
DEFAULT CAL DATA (CAL menu page 3 of 4)

After trying again the CAL automatic calibration amptd. If it works well do not forget CAL STORE. Then redo the other calibrations.

Yves
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- EremitaAnalogico @ Tardz on Nov 12, 2019 2:46 AM
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  Hi, thanks for reply, but I have already do the passcode entry with -37 Hz
  Then the cal procedure not start (cal signal not found), or start with "span sens fail" error at end if I provide an external cal signal slight decentered in frequency to fool the analyzer.
  The internal cal frequency and amplitude is correct.
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  - Tardz @ EremitaAnalogico on Nov 12, 2019 8:38 AM
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    Hi,
    I have already experienced this problem of losing all calibration constants, and in my case it was worse because I could not read on the screen because it was unsynchronized. In short, in my case I placed the display settings first, of course, then the reference 300 MHz and finally I had the calibration flatness manually. After that I could use the other automatic calibrations.
    The internal calibrator is at 300 MHz, it comes from a multiplication of a reference to 10 MHz. You must first adjust this calibration constant:
    FREQUENCY
    -2001 HZ
    CAL
    MORE 2 of 3
    CAL SERVICE
    CAL TIMEBASE
    you have value from 0 to 255
    you must adjust frequency to 300 MHz ± 75 Hz (± 0.25ppm)
    If you have no other instrument to accurately measure 300 MHz frequency, set the middle value of 128 to begin, you can change it later.
    Try to do the frequency calibration CAL FREQ.
    If the frequency calibration PASS, try calibration in AMPL. If ever the FAIL calibration, do the FLATNESS calibration, then retry the amplitude calibration.
    
    Yves
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    - EremitaAnalogico @ Tardz on Nov 12, 2019 11:55 PM
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      Hi, my analyzer also had out of sync monitor, but I have solved by erasing one more time the entire memory. When powered up, luckily the monitor was in sync.
      Regarding the calibration signal out of analyzer, the frequency is out less than 1 KHz below 300MHz
      The amplitude is -19,59 dBm:
      
      I have entered the commands that you have suggested, but I can't find CAL TIMEBASE menu item in Service Cal menu.
      Here my screenshot. Perhaps I have another version of firmware?
      
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      - Tardz @ EremitaAnalogico on Nov 13, 2019 8:36 AM
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        OK, you don't have to do CAL TIMEBASE calibration for HP8590B model, sorry. This spec below
        
        go to FLATNESS DATA (edit DATA), probably the cause of this step in level because you have to chart, one below 50MHz and another above 50MHz. After this step, freq & ampl calibration normally will work.
        
        Yves
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        EremitaAnalogico @ Tardz on Nov 13, 2019 11:19 PM
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        Hi Tardz, thanks for your assistance.
        I can do very few things when I enter Flatness Data menu.
        If I select Edit Flatness I get an error on the left of screen
        Store Flatness and Init FLT only give an OK quickly after I press respective keys.
        
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        Tardz @ EremitaAnalogico on Nov 14, 2019 7:42 AM
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        Hi, try this procedure:
        Yves
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        Tardz @ Tardz on Nov 14, 2019 11:09 PM
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        Hi,
        I've done yesterday, the FLATNESS calibration procedure for my 8595E and this is result below:
        
        Now this sequence to do for your 8590B is below:
        
        First, setup on your 8590B
        - Center FREQ at 300 MHz
        - CF step 50 MHz
        - span 10 MHz
        - resBW 1MHz
        - marker peak
        - signal track ON
        - ajust RF signal of your generator to have -14dBm on your 8590B
        - This is the REFERENCE point, if you have a relative mode on your precision milliVoltmeter, enable it now => reading must be 0.0 dB at 300 MHz.
        - For each Frequency in the chart, note the relative level on your precision milliVoltmeter when the RF level is -14dBm on your 8590B. Use step CenterFREQ and peak marker at each frequency for your help.
        
        When you chart is completed, it's will be time to store these calibration factors.
        PRESET
        and follow these steps below.
        
        Yves
        
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        Tardz @ EremitaAnalogico on Nov 15, 2019 9:51 AM
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        Hi,
        "I can do very few things when I enter Flatness Data menu.
        If I select Edit Flatness I get an error on the left of screen
        Store Flatness and Init FLT only give an OK quickly after I press respective keys."
        
        When you hit the Edit Flatness key you got an error (that's normal) because you have to clear the contents before writing with the INIT FLT key. However, this key allows you to see the current content without altering it. By pressing the UP and DOWN arrows, you will see the current calibration factors. The first point that will be asked when you have all the measurement points described in the table will be the one at 4MHz.
        
        The calibration point table was taken from document 5958-7098 for the 8590B and 8592B, and I do not see a point at 4MHz. If you press the UP and DOWN keys or the wheel, you will see at which frequencies you should have the measuring points. The last image from 8591A show calibration table with a starting point of 4MHz. By checking the other points with the UP and DOWN key, you will see if it corresponds to this table, if so, then it is this table that you must follow to find your calibration points ... the version of the table depends on doubt the firmware version installed.
        
        On the second image, it's my spectrum 8595E, and the trace on screen shows calibration factors of my spectrum. In your case, the trace is flat.
        
        Yves
        
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8590B no calibration after memory loss

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