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

[Chris Hastreiter]

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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