Cal Ram Checksum Error; Operating Hints; Equipment Required - HP 54520 Series Service Manual

Calibrating and Adjusting
This chapter provides firmware and hardware calibration and adjustment procedures
for the HP 54520 and 54540-Series oscilloscopes. Primary adjustment groups are the
following:
e Power Supply Adjustment
e Main Assembly Calibration and Adjustment
e CRT Monitor Assembly Adjustment.
Equipment Required
Equipment required for adjustments is listed in table 1-1, "Recommended Test
Equipment", in chapter 1 of this manual. Any equipment that satisfies the critical
specification listed in the table may be substituted for the recommended model.
Equipment for individual procedures is listed at the procedure.
Calibration Interval
There are two types of calibration for the HP 54520 and 54540-Series oscilloscopes.
The firmware calibration is the self cal (self-calibration). Self-calibration should be
done every year, or every 2,000 hours of operation, whichever comes first. The
hardware calibration consists of adjustment of the power supply, high-frequency
pulse response, and CRT display. These adjustments only need to be done under
circumstances set by certain needs, which are explained in other areas of this guide.
The need for calibration or adjustment will also depend on your experience.
For replacement assemblies, adjustments are set at the factory when assemblies are
tested. However, some adjustment may be necessary after an assembly has been put
into the instrument. Usually the only assembly that requires adjustment is the
assembly replaced.
Cal RAM Checksum Error
If power is applied to the instrument and the message "cal ram checksum error re-cal
instrument" is displayed, all firmware calibration procedures must be performed. See
"To calibrate the firmware" in this chapter.
If the instrument does not pass the firmware calibration, repair is necessary.
Operating Hints
Some knowledge of operating the HP 54520 and 54540-Series oscilloscopes is helpful.
However, procedures are written so that little experience is necessary. The following
hints will speed progress of the procedures.
When using many averages, it often takes awhile for a waveform display to stabilize
after a change. When a front panel control on the oscilloscope is changed, averaging
automatically restarts. When the input signal or an adjustment is changed, the
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