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34461A Down Arrow Key Failure, Possible Firmware Bug?

Question asked by jmgeller on Dec 27, 2013
Latest reply on Jan 2, 2014 by jmgeller
==> See Jan 2, 2014 post below, problem understood, easy work-around!

On using the histogram manual bin settings, I notice that the down arrow (under the select button) often hangs and is no longer operative for a time.  The up arrow still works.  It was unclear if the button, related electronics, or the firmware was failing.  I was leaning towards an intermittent button, however, another user reports similar problems, so now it is more likely a firmware fault.  

For example, setting 1.018 V, the 8 can be advanced to 9 using the up arrow (increment), but no longer decremented lower to 7.

I found a set of steps that seems to make a repeatable failure (copied below).  However, on repeated tries, the down arrow key often hangs part way into the steps.  

It would be interesting to see if the down arrow key failure repeats on other 34461As.  This is 34461A S/N 325, Ver. 1.09.  Perhaps someone will see the exact nature of the algorithm failure (if there is one).

Also, I realized the value being set was outside of the range of the 100 mV auto range setting for no input on successive tries, however connecting a 1 V source (e.g. 1.018 V) so the DMM auto-ranges to a "valid" range, then repeating the steps seems to lead to the same failure.

Apology in advance if I missed something, and the settings are an illegal or illogical operation being properly prevented by the 34461A.

As an aside, It would fantastic if in future versions there could be a numeric key pad, just like the upgrade from the spin wheel on the 33120A generator to the numeric key pad on the 33210A (a huge improvement in user experience!).  For numeric entry (e.g. histogram center or span), the regular keys could morph into a numeric key pad (numbers in a different color near the numeric keys?), or a touch screen could be used to provide the numeric key pad.  I realize the front panel space is limited.

The sequence:

from factory reset:
 
Display
Histogram
 
Binning
Manual
 
Bin Settings
400
 
Center
1.018 700mV
 
Span
100.000 00nV
 
Back to Center
Highlight "7" in 1.018 700mV
 
The down arrow (under "select") no longer works
The up arrow works

Edited by: Joe Geller on Jan 2, 2014 9:07 AM  

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