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  1. HP-Agilent-Keysight-Equipment
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HP 3456A repair/restore

 

Hi all,
I recently got a 3456A with a missing power button/knob (some of you may have seen my attempts to source a replacement, still not conclusive), and getting some bench space I thought I'd pull it from the shelf and testing it in a bit more depth.
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One other issue I'm seeing is with the keyboard (which, from some preliminary research here and elsewhere, may be using the "Bill West Switch" design), which works, but the actuation feel is not very firm or "clicky" (which I can live with), but (which I can't live with), pressing a button returns a long chain of actuations - meaning that if I press "6" to enable to 6.5 digit mode, I get "666666" on the screen. Trying to get into 100 NPC mode is a Zen exercise (or maybe, better put, karate... I need to make my pressing .001s long to get just a "1"). I assume this is purely mechanical (needing maybe some cleaning of the keyboard contacts?...).?
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For some reason, the Keysight provided Operating and Service Manual is missing the Section 4 and further in its TOC (can anyone provide the missing pages, please?), which seems to be the case for other sources (though I haven't yet looked into Artek), and so I'm sill perusing the manual to find directions for accessing the keyboard for servicing. But regardless, I wonder if this is a common issue and if some good pointers are available from those having been through this issue. A search in the archives for 3456A doesn't return much, though I think I need to dig deeper for the "Bill West Switch" posts which seem to be plentiful.
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Thank you in advance for all input!
Radu.?
 

I just purchased the Artek manual(s), which I assume (99.99% certain...) have the missing TOC pages. In good part just for supporting them.... Hopefully they get delivered to me expeditiously.?
 

The BAMA library has a manual version with the missing pages - the "high res" version. But that's the only one. So for anyone looking for those, that's where to find them.?
 

Getting pretty intermittent time for this, and mostly reading time, rather than bench, I've been studying a bit the calibration procedure (the meter seems to be about 25ppm high at 10V). I searched a bit the archives - though probably not enough - but didn't yet find anything on the issue below.?
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At p.5-2, 5-14 Adjustment Procedure step h through x, there's a very elaborate procedure for what seems at a rather cursory glance a null adjustment on the meter. How have others done this? I assume there's a simpler procedure folks apply to this step, possibly involving fewer instruments (they want no less than a Fluke 750A, a 731B, a DC Standard, and a null meter). I can't say I have a lot of clarity on what the whole procedure is exactly supposed to accomplish, or how it interacts with the meter ("Null math feature" is involved, for instance) - I haven't gotten enough quality time with this meter. Can anyone with familiarity with the procedure possibly shed some light on this??
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Thank you,
Radu.?
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