AnsweredAssumed Answered

HP54504A loses Selfcalibration Data

Question asked by POW on Nov 16, 2010

i got a nice used HP 54504A Scope, but it has a failure: if i start it with rear-switch set to PROTECTED, i get an error:

cal ram checksum error
re-cal instrument

So i switched to UNPROTECTED, switched on the scope and it loaded it`s default values:

default cal loaded
re-cal instrument

I recalibrated it via the utils and service menu, so that all CAL values showed a P for PASSED in the utils/self cal menu (i didn`t open the scope for the internal adjustments).

After this procedure and running without switching off i get for all selftests PASSED.

But if i turn it off, set the switch to PROTECTED and switch it on again, i`ll get the error above again:
cal ram checksum error
re-cal instrument

I get the error, too, if i switch to PROTECTED directly after calibration an before switching it off.

I may assume at least one problem:
- i am not doing the correct self-calibration procedure
- i`ve got a problem with the non-volatile DALLAS SRAM.

Please, could anybody help to get my calibration data correctly stored  ?

Kind Regards,

D. Powah