I noticed that HP made a particular choice about connecting the ground side
lamp power supply. HP use a coaxial cable between the physical assembly and a
connector mounted on the chassis, then a single + 20V wire is connected to the
voltage regulator board, while the chassis acts as a
Luciano,
I agree entirely!
I like the motto "do no harm"!
When I try a mod such as replacing the dead op amp on the A9 board. I
make before and after tests to make sure no degradation has occurred.
Since this means parts in 10 -14th AD at 128 Seconds most don't have the
capability. However a
er people.
>
> thankyou , Luciano
>
> Luciano P. S. Paramithiotti
> tim...@timeok.it
> www.timeok.it
>
> Da "time-nuts" time-nuts-boun...@lists.febo.com
> A "Discussion of precise time and frequency measurement"
> time-nuts@lists.
Luciano P. S. Paramithiotti
tim...@timeok.it www.timeok.it Da "time-nuts"
time-nuts-boun...@lists.febo.com A "Discussion of precise time and frequency
measurement" time-nuts@lists.febo.com Cc Data Tue, 4 Aug 2020 13:32:31 -0400
Oggetto Re: [time-nuts] "The Pe
tim...@timeok.it writes:
> Another important point is that of the certainty of the results
> of a change. I mean that most hobbyists who have a 5065A, including
> me, do not have the opportunity to measure the proposed improvement
> effects, first of all because they do not have a
of precise time and frequency measurement"
time-nuts@lists.febo.com
Cc
Data Tue, 4 Aug 2020 13:32:31 -0400
Oggetto Re: [time-nuts] "The Penultimate HP5065 A15"
Hi
If a more extensive rebuild is in the works …..
+/-20V is (as has been observed) not an ideal vol
Hi
> On Aug 4, 2020, at 5:23 PM, Poul-Henning Kamp wrote:
>
>
> Bob kb8tq writes:
>
>>> The "modern" approach to that is to modulate or dither with a
>>> good long PRNG to whiten the noise, and while good in theory,
>>> it is not _that_ easy to get right in practice.
>>
>> Of course
Hi
> On Aug 4, 2020, at 3:50 PM, Poul-Henning Kamp wrote:
>
>
> Bob kb8tq writes:
>
>>> I have not given much thought to A11 yet, and I do find a certain
>>> elegance in the wien-bridge approach. It is worth noting that the
>>> actual heaters run of the unregulated supply, when I
Bob kb8tq writes:
> > The "modern" approach to that is to modulate or dither with a
> > good long PRNG to whiten the noise, and while good in theory,
> > it is not _that_ easy to get right in practice.
>
> Of course one could simply cave in to the fact that for the sort of
> gain
Bob kb8tq writes:
> > I have not given much thought to A11 yet, and I do find a certain
> > elegance in the wien-bridge approach. It is worth noting that the
> > actual heaters run of the unregulated supply, when I stabilized
> > that, A11 worked less hard.
>
> The AC bridge approach
Hi
> On Aug 4, 2020, at 3:07 PM, Poul-Henning Kamp wrote:
>
>
> Bob kb8tq writes:
>
>> If a more extensive rebuild is in the works …..
>
> Yes, that's where we're headed eventually, but I prefer to do it
> incrementally.
>
>> +/-20V is (as has been observed) not an ideal voltage for
Bob kb8tq writes:
>If a more extensive rebuild is in the works …..
Yes, that's where we're headed eventually, but I prefer to do it
incrementally.
>+/-20V is (as has been observed) not an ideal voltage for “modern”
>electronics.
Right, and being able to drop that down later is in the
Hi
> On Aug 4, 2020, at 2:49 PM, Poul-Henning Kamp wrote:
>
>
> Bob kb8tq writes:
>
I would go for the LTZ1000 if you can. The LM399 has gone out of
fashion for a reason: [...]
>>>
>>> Yes, I know, being also a volt-nut :-)
>>>
>>> Problem is, the A15 PCB isn't all that
Bob kb8tq writes:
>>> I would go for the LTZ1000 if you can. The LM399 has gone out of
>>> fashion for a reason: [...]
>>
>> Yes, I know, being also a volt-nut :-)
>>
>> Problem is, the A15 PCB isn't all that big, and if you want
>> cooling fins on two TO220's, a lot if it just got
On 8/4/2020 10:21 AM, cdel...@juno.com wrote:
>
> Back in Nov 2017 I detailed my A15 mods:
>
> Set Zener current to minimum TC (I achieved < 1PPM/C at the +20V output)
> This involved disconnecting the C-field circuit and replacing it with a
> dual (in series ) LM299AH and 1PPM resistors.
Hi
If a more extensive rebuild is in the works …..
+/-20V is (as has been observed) not an ideal voltage for “modern” electronics.
If you dig into each of the boards, there is a lot of “drop it down right now”
regulation
done on a board by board basis. More or less what might be there:
A1
>> C-field polarity switch. An experiment. If nothing else
>> I will be able to measure the residual magnetic field.
There is no requirement to do any thing other than switch the C-field
polarity.
No optical stuff needed.
The PRS10 switches the C-field polarity at a 5HZ rate to
Hi Poul-Henning,
On 2020-08-04 12:35, Poul-Henning Kamp wrote:
>
> Magnus Danielson writes:
>
>> If that is the range you aim to improve, then I strongly recommend you
>> do re-read the postings I did about phase noise in detector range, as I
>> have showed that phase-noise get's mixed
Magnus Danielson writes:
> If that is the range you aim to improve, then I strongly recommend you
> do re-read the postings I did about phase noise in detector range, as I
> have showed that phase-noise get's mixed down to DC and increase the
> noise there. With very ugly and hand-wavey
Hi Poul-Henning,
On 2020-08-04 00:32, Poul-Henning Kamp wrote:
>
> Attila Kinali writes:
>
>>> The main reason I dont just repair/replace the A15 is that
>>> I want to find out how much instability the PSU contributes.
>> There are very few points where supply voltage (in)stability
>>
Hi
> On Aug 3, 2020, at 6:32 PM, Poul-Henning Kamp wrote:
>
>
> Attila Kinali writes:
>
>>> The main reason I dont just repair/replace the A15 is that
>>> I want to find out how much instability the PSU contributes.
>>
>> There are very few points where supply voltage (in)stability
> On 04 August 2020 at 10:32 Poul-Henning Kamp wrote:
>
>
>
> Attila Kinali writes:
>
> >> The main reason I dont just repair/replace the A15 is that
> >> I want to find out how much instability the PSU contributes.
> >
> >There are very few points where supply voltage
Attila Kinali writes:
>> The main reason I dont just repair/replace the A15 is that
>> I want to find out how much instability the PSU contributes.
>
>There are very few points where supply voltage (in)stability
>contributes to long term frequency drift in a Rb vapor cell standard.
Hoi Poul-Henning,
On Fri, 31 Jul 2020 21:31:13 +
"Poul-Henning Kamp" wrote:
> The main reason I dont just repair/replace the A15 is that
> I want to find out how much instability the PSU contributes.
There are very few points where supply voltage (in)stability
contributes to long term
Having one of the best HP5065A Rb's that Corby has seen right at 4 E-14 at 200
and 400 sec. I have been hands off. My age and macular hole on my right eye has
impacted my hardware work. A recent test also shows very low aging over a 9
month period. But last September my environmental monitor
tim...@timeok.it writes:
>A better C field generator is necessary and the LM399 remains a good
> solution. It would be interesting to add
> barometric pressure compensation.
I don't think I can fit that also :-)
> Two types of setting could be used to adjust the C field, one with
Regarding 5065 "A15"
When I was about to repair my 5065, the first thing I noticed was the
quite high "+22-30V" and its impact on the dissipated heat from the
series regulator Q1. Therefore, I replaced the power transformer T1
and the rectifiers with a linear regulated power supply providing
to this project.
Luciano
Luciano P. S. Paramithiotti
tim...@timeok.it
www.timeok.it
Da "time-nuts" time-nuts-boun...@lists.febo.com
A time-nuts@lists.febo.com
Cc
Data Fri, 31 Jul 2020 21:31:13 +
Oggetto [time-nuts] "The Penultimate HP5065 A15"
The A15 board in one of my 5065s is in bad shape, and I have started
to look at designing a plug-compatible replacement board.
The main reason I dont just repair/replace the A15 is that
I want to find out how much instability the PSU contributes.
The outline idea currently is:
LM399
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