Susan,
With the 16047A test fixture fitted, I performed the open compensation.
Then I inserted a copper short (as shown in the HP manual) and performed the
short compensation. It was after that compensation that I was still getting
'interesting" readings.
I am really unclear, based on the schematic how the battery could cause
problems storing the open and short compensation constants in the permanent
RAM once the power is on. According to my understanding of the schematic,
when the 5 Volts is present (power good) Q3 saturates and shorts out the
blocking schottky diode CR1 and that puts 5 Volts on the U12 D4364C-15L
Memory chip. At the same time it charges up the battery thru the series 470
Ohm resistor.
The battery is 2.6 Volts with the unit off and 3.3V while it is on and
charging.
However, the gentleman who sold me the unit informs me that the battery can
cause problems with the memory holding the open and short calibration
constants. So maybe the battery gets replaced no matter what.
Steve
Steven A. Hogan
The Sound Steward
1606 West Southgate Avenue
Fullerton, CA 92833-3851
www.soundsteward.com
(714) 871-6636 phone
(714) 904-6636 cell
(714) 871-0640 fax
_____
From: hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...] On Behalf Of Susan Parker
Sent: Sunday, November 21, 2010 8:38 AM
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: 4276A LCZ analyzer needs
cal/adjustment,paper manual, standards.
Hi Steve,
I have a HP 4274A and it needs to be "open" and "short" calibrated with
the appropriate test fixture fitted before use, otherwise the results
can be "interesting".
has a sales spec PDF scan.
That's the two buttons under ZERO just left of center.
Easy to use :)
1. Without anything fitted, press "open".
Unit goes through it's compensation frequency range steps.
2. Short out the 2 test terminals, press "short".
Unit goes through it's compensation frequency range steps.
3. Should now be ready to use.
Assuming the backup battery is okay, you should be able to store the setup.
Remember to recalibrate if you change the test method/jig.
I would try checking with non-electrolytic film capacitors first, as
they can be a bit funny if not measured with a bias voltage.
Best wishes,
Susan.
