[time-nuts] Re: Turning off display on HP 58503 A or B

[Lon Cottingham]

Chris,
Thanks for the reply.  I have made just such a mod to one of my 58503's.
 It was in a discussion of this
 mod that the idea arose that  HP had built in such a command.  But, no one
had actual knowledge of such
 this hidden command.  It was most probably just wishful thinking. Thanks
again for your comments.
73 de Lon , K5JV






On Mon, Jun 6, 2022 at 11:33 PM Chris Hastreiter via time-nuts <
time-nuts at lists.febo.com> wrote:

> I'm not aware of any command to turn off the display - I haven't seen it in
> the manual, but I think that it might use the same display interface as the
> 53131A counter.  For that unit I've added a two pole switch that allows me
> to turn off the anode and filament voltages to the display when I'm not
> using it.  You could measure the voltages on your interface cable and see
> if it matches the 53131A schematic and if so do something similar.
>
> Chris
>
> On Fri, Jun 3, 2022 at 5:47 PM K5jv via time-nuts <
> time-nuts at lists.febo.com>
> wrote:
>
> > I was recently evolved in a discussion about the HP 58503 option 001
> > display.  The general idea is that there is some command to tune the
> > display on or off.  A few ideas were offered but no one had anything
> except
> > "they heard about it."   I have found nothing on the subject from old HP
> > literature.  Comments would be appreciated.  I am not talking about
> turning
> > the power off to the DC/DC converter.
> >
> > On a different subject:  A couple of month back I got some strong
> > criticism about suggesting that the oven in the Z3801A was a potential
> > source of problems.   I just got another Z3801A in for repair.  Same
> > symptoms as before;  appears to turn on normally but after a while goes
> > into holdover and stay there,  same LH flat lines.  Once again the
> problem
> > turned out to be the oven.  It was unusually hot to the touch.  Changing
> > the oven solved the problem.  Now my question.  I have never opened one
> of
> > these oven, so have no real idea exactly what is inside.  I would
> suspect
> > that one of  the oven's thermostats is stuck in the "on" position.  Since
> > it is a "double oven",  there could be two thermostats?   If these are
> > mechanical contacts, as one might expect fro the 1995 era, can they be
> > cleaned or replaced?   Comments from anyone who has actually seen inside
> > one of these ovens would be appreciated.
> >
> >
> > 73 de Lon, K5JV
> > 281-795-1335
> >
> >
> > [a96323c7-47c0-46b2-8018-f039618476d5]
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