[time-nuts] Re: HP 5061Bs on ebay

[Bob Camp]

Hi

There are a *lot* of 5061 chassis running around. There are *very* few working 
tubes to go with those chassis.  The tubes wear out, but the chassis gets kept
“just in case”. 

It is not unusual to buy a half dozen or more in order to find one with a tube that 
“kinda sorta” works. Many of the ones that do get running are not very close to 
their original spec performance. (The stability of the unit degrades as the tube 
wears out …..)

For a while FEI had a contract to supply replacement tubes to the US government. 
You will find those tubes in some units. You also will find units with tubes out of other
brands of Cs standards. How well those work is a bit of a “that depends” sort of thing. 

None of this is to say “don’t do this”. It only is a caution that the route from having
nothing to having a good performance unit may be pretty long. You might get lucky
early on …..

Bob

> On Jun 14, 2023, at 6:09 PM, Ke-Fong Lin via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hi everyone,
> 
> So unfortunately, no, I won't be able to buy the newly introduced
> 5071B (or rather revamped 5071A) :)
> 
> However, and you probably know already, there's a few 5061Bs from one
> particular seller.
> They're pretty tempting, and I'm considering making an offer.
> 
> They seem to be later models (late 80s), and some of them even have
> "tube good" or "tube ok" sticker on them.
> Some are missing bits and pieces (like HV supplies) but with the
> cesium tube. And it seems that parts other than the cesium tube, are
> easy to find (lots of 5061 with dead tubes to scavange from).
> A few seem even customized, perhaps by Frequency Electronics? For
> internal use? Seems that they've added some monitoring circuitry.
> 
> Any comment, especially on the tubes, their remaining life or lack thereof?
> Still a project, but that's really something I start considering.
> 
> Best regards,
> 
> -- 
> /* Lin Ke-Fong
> * anotherlin at gmail.com
> * I always do what I say, especially if it's something stupid.
> */
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