Turning off display on HP 58503 A or B
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]
Hi
Both control loops in the 3801 OCXO’s are thermistor based. If the outside loop
goes nuts, the device might survive. If the inside loop shorts out, the normal
result is a melt down of the OCXO innards.
Bob
On Jun 2, 2022, at 9:55 AM, K5jv via time-nuts time-nuts@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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Hi Lon, hello to all members.
In 1995 the art of temperature control was a good bit more advanced,
and a bi-metal thermostat would not be stable enough These ovens have a
semiconductor temperature control; so I would suspect a shorted
transistor.
These failures in OCXO are not that rare, and that is why there are
thermal safety fuses. And please don't defeat them !
73 from Claude VA2 HDD
Le 02/06/2022 13:55, K5jv via time-nuts a écrit :
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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]
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Am 2022-06-02 19:55, schrieb K5jv via time-nuts:
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
1965 ???
from anyone who has actually seen inside one of these ovens would be
appreciated.
I had a Morion MV-89A that stopped oscillating when the tune voltage
was > 0.8V. I opened it and recovered the SC 5 MHz crystal. It had
parameters that could be expected from such a crystal, quite good.
The xtal parameters were not too different between room temperature
and 85°C, stability obviously excluded. It is possible to do most
development work for a new oscillator without burning one's fingers
too often.
There is one thermistor in the inner oven; in the outer oven
there is probably sth. else, but nothing mechanical.
<
https://www.flickr.com/photos/137684711@N07/49585174873/in/album-72157662535945536/
and from there to the right.
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@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]
time-nuts mailing list -- time-nuts@lists.febo.com
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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@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@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]
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
time-nuts mailing list -- time-nuts@lists.febo.com
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