Thanks.? I get 4 errors:
612, 613, 618, 619
Three of these have to do with resistance, maybe I needed to short the input, but as resistance works (I just tried with a range of high precision resistors from 1 ohm to 10 meg) and everything looks good so I will ignore those for now.
The 618 error is DC high voltage attenuator failure so that seems to be the issue.
Maybe it is a relay failure.
Thanks for this hint to get me in the right direction.
Peter
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On 3/5/2025 3:44 PM, Razvan Popescu via groups.io wrote:
Hello Peter,
Try to run a Self Test and see if it passes it.
Could be anything but older 34401A have relay faults. The OMRON relays
can be found but not the COTO relay. Newer 34401A had a newer part
instead of the COTO one but from what I remember that is also unobtainable.
Regards,
Razvan
On 05/03/2025 21:35, Peter Gottlieb via groups.io wrote:
I have an Agilent 34401A which I've used at my bench for many years.
Today I went to measure a 12 volt battery and it just started clicking.
I tried it on a power supply and auto ranging works fine up to 12 volts
where it starts clicking about twice a second.? Trying manual range,
going over the 10 volt range shows exactly zero volts to any input.
I am guessing it tries autoranging higher, sees the zero, then tries to
go lower, then repeats.
This is only on DC volts.? AC volts and resistance (didn't check
current) are fine, for example I can plug the leads into an outlet and
it shows 120 VAC just fine.
Before I dig in, is anyone familiar with this fault?
Peter
