cal ram checksum error (HP 54501A)

[whywhy]

I have a HP 54501A Digitizing scope.

After every single startup I get an error message "cal ram checksum error, re-cal instrument"

After re-calibration the scope works good.

If I ignore the error message and run the SELF TEST with TEST ALL option the following three lines returns with FAILED message

1.Protected Non-Volatile RAM
2.D/A converter
3.A/D converter

The question is: Is it an easy to handle tipical failure (broken backup battery or something like this) or it signs a more serious problem?

thanks in advance
z.lauri

[AnalogKid2DigitalMan]

Any mention of such issues in the manual? HP would probably a better source to ask for answers.

[whywhy]

citation from the manual:

"If the HP 54501 A fails any selftest perform the following:
1, recalibrate  the oscilloscope
2, If that doesn't fix the problem refer to the service manual

🙂

Ok, I recalibrate but why after every startup?

HP would probably a better source to ask for answers.

I have put it also there. The more source the more info

... I think...

[whywhy]

I took a closer look inside the instrument. I found this

h**p://www.maxim-ic.com/quick_view2.cfm/qv_pk/2648

ram in it.

Im almost shure that the litium cells inside the package are broken. Since this IC isn't available in my territory I will have to try to replace the cells.
Since I didn't find any detailed description about the structure of this IC so I dont know what can exacly be found in the package. Can this package be disassembled and can the cells be separated from the chip?

Has anybody ever met such problem?

[kbosak]

Hi, I have very similar symptoms with teh same model of the oscilloscope.
Plus, on my oscilloscope using SAVE then RECALL setting doesn't work if I switch off the osc in the meantime.

I am not sure if I would see A/D D/A error selftest (as far as I remember it was always fine).

I would like to know if replacing this single chip helped or how did you exactly solved the problem?
Than you very much in advance!

[tomartin]

On my scope the switch on the backside named "calibration"

solved the issue when set to "unprotected".

When the scope arrived at my place it was set to "protected" and the same error messages from the selftest arised.

kind regards

Tom

[frengo]

I've a HP 54501a. The display shows the following message: address error 00005E4EH, to clear cycle power with one front panel key pressed .If the error condition remanins please consult the service manual. 

Noboby key works, and the same message remains. Could be the Nvram who doesn't works correctly. The nvram is a dallas ds 1235Y type, impossible to change battery. Who can help me?. Thanks 

[dobarni]

Hi Frengo,

You should probably ask HP support for help, unless the behavior you've seen is somehow related to National Instruments software or hardware. In that case we would need a more detailed description of the issue.

Thanks for understanding. 

Regards,

Barna D.

National Instruments 

[SwannyEng]

I have an HP 54501A and the power supply went bad.  Please provide recommendations on how to repair or replace this part.  Perhaps I can find another malfunctioning 54501 that still has a good power supply...

Thank you!

[Dennis_Knutson]

Agilent

Don't see any reason at all for you to post here.