FS
Frank Stellmach
Wed, Jan 28, 2015 11:28 AM
Hello Joe,
yes the cap consists of two parts.
The upper one serves for thermal isolation of the LTZ1000A TO99 case
against the environment and therefore reduces the power dissipation of
the oven.
The part on the solder side is much more important, as it covers the
solder joints and avoids air draught over these pins. That avoids these
low frequency voltage variations, which are mentioned in the LTZ data sheet.
Anyhow, there are no further shieldings around the PCB, so the solder
joints of the OP Amp and the precision resistors are exposed to that air
draught, maybe from the fan.
That's a further engineering fault they made on this reference.
(The other faults are the 95°C oven temperature, the use of the A
version instead of the non A, and the use of R417,200k temperature
compensation resistor, which is necessary for the non A version only.)
The hat is not included in the BOM inside the CLIP, therefore can not be
ordered from HP, obviously.
It is a smooth, shiny plastic, resembles the one used around the LM399H.
Wasn't latter one something like polysulphone?
Maybe suitable pieces of polystyrol foam will do the job also.
Frank
Hello Joe,
yes the cap consists of two parts.
The upper one serves for thermal isolation of the LTZ1000A TO99 case
against the environment and therefore reduces the power dissipation of
the oven.
The part on the solder side is much more important, as it covers the
solder joints and avoids air draught over these pins. That avoids these
low frequency voltage variations, which are mentioned in the LTZ data sheet.
Anyhow, there are no further shieldings around the PCB, so the solder
joints of the OP Amp and the precision resistors are exposed to that air
draught, maybe from the fan.
That's a further engineering fault they made on this reference.
(The other faults are the 95°C oven temperature, the use of the A
version instead of the non A, and the use of R417,200k temperature
compensation resistor, which is necessary for the non A version only.)
The hat is not included in the BOM inside the CLIP, therefore can not be
ordered from HP, obviously.
It is a smooth, shiny plastic, resembles the one used around the LM399H.
Wasn't latter one something like polysulphone?
Maybe suitable pieces of polystyrol foam will do the job also.
Frank
JL
J. L. Trantham
Wed, Jan 28, 2015 2:00 PM
Frank,
Thanks for the info. I've wondered about that.
In the days of 3D printers and CAD/CAM, it might be possible to have a 'run' of these 'made to order', so to speak.
I wonder if Linear Technology would have any information about them?
Thanks again.
Joe
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Frank Stellmach
Sent: Wednesday, January 28, 2015 5:28 AM
To: volt-nuts@febo.com
Subject: [volt-nuts] plastic caps on 3458A reference board
Hello Joe,
yes the cap consists of two parts.
The upper one serves for thermal isolation of the LTZ1000A TO99 case against the environment and therefore reduces the power dissipation of the oven.
The part on the solder side is much more important, as it covers the solder joints and avoids air draught over these pins. That avoids these low frequency voltage variations, which are mentioned in the LTZ data sheet.
Anyhow, there are no further shieldings around the PCB, so the solder joints of the OP Amp and the precision resistors are exposed to that air draught, maybe from the fan.
That's a further engineering fault they made on this reference.
(The other faults are the 95°C oven temperature, the use of the A version instead of the non A, and the use of R417,200k temperature compensation resistor, which is necessary for the non A version only.)
The hat is not included in the BOM inside the CLIP, therefore can not be ordered from HP, obviously.
It is a smooth, shiny plastic, resembles the one used around the LM399H.
Wasn't latter one something like polysulphone?
Maybe suitable pieces of polystyrol foam will do the job also.
Frank
volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
Frank,
Thanks for the info. I've wondered about that.
In the days of 3D printers and CAD/CAM, it might be possible to have a 'run' of these 'made to order', so to speak.
I wonder if Linear Technology would have any information about them?
Thanks again.
Joe
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Frank Stellmach
Sent: Wednesday, January 28, 2015 5:28 AM
To: volt-nuts@febo.com
Subject: [volt-nuts] plastic caps on 3458A reference board
Hello Joe,
yes the cap consists of two parts.
The upper one serves for thermal isolation of the LTZ1000A TO99 case against the environment and therefore reduces the power dissipation of the oven.
The part on the solder side is much more important, as it covers the solder joints and avoids air draught over these pins. That avoids these low frequency voltage variations, which are mentioned in the LTZ data sheet.
Anyhow, there are no further shieldings around the PCB, so the solder joints of the OP Amp and the precision resistors are exposed to that air draught, maybe from the fan.
That's a further engineering fault they made on this reference.
(The other faults are the 95°C oven temperature, the use of the A version instead of the non A, and the use of R417,200k temperature compensation resistor, which is necessary for the non A version only.)
The hat is not included in the BOM inside the CLIP, therefore can not be ordered from HP, obviously.
It is a smooth, shiny plastic, resembles the one used around the LM399H.
Wasn't latter one something like polysulphone?
Maybe suitable pieces of polystyrol foam will do the job also.
Frank
_______________________________________________
volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
A
acbern@gmx.de
Wed, Jan 28, 2015 5:27 PM
this would be over-engineered, unless you have a lot of spare time or want to do this for fun. If you use plastic supports as they were used when these TO packages were common (these supports should still be available, they surround all pins and quality plastics were standard) and use any cap in addition on top of the case, thats enough blocking of airflow. you would put that into a closed box anyhow, with no air flow through fans or so.
Gesendet: Mittwoch, 28. Januar 2015 um 15:00 Uhr
Von: "J. L. Trantham" jltran@att.net
An: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Betreff: Re: [volt-nuts] plastic caps on 3458A reference board
Frank,
Thanks for the info. I've wondered about that.
In the days of 3D printers and CAD/CAM, it might be possible to have a 'run' of these 'made to order', so to speak.
I wonder if Linear Technology would have any information about them?
Thanks again.
Joe
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Frank Stellmach
Sent: Wednesday, January 28, 2015 5:28 AM
To: volt-nuts@febo.com
Subject: [volt-nuts] plastic caps on 3458A reference board
Hello Joe,
yes the cap consists of two parts.
The upper one serves for thermal isolation of the LTZ1000A TO99 case against the environment and therefore reduces the power dissipation of the oven.
The part on the solder side is much more important, as it covers the solder joints and avoids air draught over these pins. That avoids these low frequency voltage variations, which are mentioned in the LTZ data sheet.
Anyhow, there are no further shieldings around the PCB, so the solder joints of the OP Amp and the precision resistors are exposed to that air draught, maybe from the fan.
That's a further engineering fault they made on this reference.
(The other faults are the 95°C oven temperature, the use of the A version instead of the non A, and the use of R417,200k temperature compensation resistor, which is necessary for the non A version only.)
The hat is not included in the BOM inside the CLIP, therefore can not be ordered from HP, obviously.
It is a smooth, shiny plastic, resembles the one used around the LM399H.
Wasn't latter one something like polysulphone?
Maybe suitable pieces of polystyrol foam will do the job also.
Frank
volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
this would be over-engineered, unless you have a lot of spare time or want to do this for fun. If you use plastic supports as they were used when these TO packages were common (these supports should still be available, they surround all pins and quality plastics were standard) and use any cap in addition on top of the case, thats enough blocking of airflow. you would put that into a closed box anyhow, with no air flow through fans or so.
> Gesendet: Mittwoch, 28. Januar 2015 um 15:00 Uhr
> Von: "J. L. Trantham" <jltran@att.net>
> An: "'Discussion of precise voltage measurement'" <volt-nuts@febo.com>
> Betreff: Re: [volt-nuts] plastic caps on 3458A reference board
>
> Frank,
>
> Thanks for the info. I've wondered about that.
>
> In the days of 3D printers and CAD/CAM, it might be possible to have a 'run' of these 'made to order', so to speak.
>
> I wonder if Linear Technology would have any information about them?
>
> Thanks again.
>
> Joe
>
> -----Original Message-----
> From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of Frank Stellmach
> Sent: Wednesday, January 28, 2015 5:28 AM
> To: volt-nuts@febo.com
> Subject: [volt-nuts] plastic caps on 3458A reference board
>
> Hello Joe,
>
> yes the cap consists of two parts.
> The upper one serves for thermal isolation of the LTZ1000A TO99 case against the environment and therefore reduces the power dissipation of the oven.
>
> The part on the solder side is much more important, as it covers the solder joints and avoids air draught over these pins. That avoids these low frequency voltage variations, which are mentioned in the LTZ data sheet.
>
> Anyhow, there are no further shieldings around the PCB, so the solder joints of the OP Amp and the precision resistors are exposed to that air draught, maybe from the fan.
> That's a further engineering fault they made on this reference.
>
> (The other faults are the 95°C oven temperature, the use of the A version instead of the non A, and the use of R417,200k temperature compensation resistor, which is necessary for the non A version only.)
>
> The hat is not included in the BOM inside the CLIP, therefore can not be ordered from HP, obviously.
>
> It is a smooth, shiny plastic, resembles the one used around the LM399H.
> Wasn't latter one something like polysulphone?
>
> Maybe suitable pieces of polystyrol foam will do the job also.
>
> Frank
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
MS
Mike S
Wed, Jan 28, 2015 5:57 PM
On 1/28/2015 9:00 AM, J. L. Trantham wrote:
In the days of 3D printers and CAD/CAM, it might be possible to have
a 'run' of these 'made to order', so to speak.
I'd think a couple of pieces of pink (non-conductive) closed cell
antistatic foam, one hollowed out a bit with a penknife, would work
well. It would both shield from airflow and provide insulation.
On 1/28/2015 9:00 AM, J. L. Trantham wrote:
> In the days of 3D printers and CAD/CAM, it might be possible to have
> a 'run' of these 'made to order', so to speak.
I'd think a couple of pieces of pink (non-conductive) closed cell
antistatic foam, one hollowed out a bit with a penknife, would work
well. It would both shield from airflow and provide insulation.
JP
John Phillips
Wed, Jan 28, 2015 6:27 PM
You have to make sure you do not over insulate. The unit does produce some
heat and the heater needs to run too. You loose temperature regulation if
the heater is running at the lower limit of its capacity. 20 to 50% of
capacity seems like a good target.
On Wed, Jan 28, 2015 at 9:57 AM, Mike S mikes@flatsurface.com wrote:
On 1/28/2015 9:00 AM, J. L. Trantham wrote:
In the days of 3D printers and CAD/CAM, it might be possible to have
a 'run' of these 'made to order', so to speak.
I'd think a couple of pieces of pink (non-conductive) closed cell
antistatic foam, one hollowed out a bit with a penknife, would work well.
It would both shield from airflow and provide insulation.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/volt-nuts
and follow the instructions there.
You have to make sure you do not over insulate. The unit does produce some
heat and the heater needs to run too. You loose temperature regulation if
the heater is running at the lower limit of its capacity. 20 to 50% of
capacity seems like a good target.
On Wed, Jan 28, 2015 at 9:57 AM, Mike S <mikes@flatsurface.com> wrote:
> On 1/28/2015 9:00 AM, J. L. Trantham wrote:
>
>> In the days of 3D printers and CAD/CAM, it might be possible to have
>> a 'run' of these 'made to order', so to speak.
>>
>
> I'd think a couple of pieces of pink (non-conductive) closed cell
> antistatic foam, one hollowed out a bit with a penknife, would work well.
> It would both shield from airflow and provide insulation.
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/volt-nuts
> and follow the instructions there.
>
--
*John Phillips*
CS
Charles Steinmetz
Wed, Jan 28, 2015 6:56 PM
I'd think a couple of pieces of pink (non-conductive) closed cell
antistatic foam, one hollowed out a bit with a penknife, would work
well. It would both shield from airflow and provide insulation.
The problem is that an LTZ1000 (or LM399) runs hot enough that most
plastics you find lying around won't stand up to it for very long
(some of them melt almost immediately when you power it up). This is
true even of polycarbonate, which is one of the most durable common
plastics, and is why the original caps were made from polysulfone.
Unfortunately, it also means that replacements may be hard to make by
3D "printing," since the process depends on melting the base material.
Best regards,
Charles
>I'd think a couple of pieces of pink (non-conductive) closed cell
>antistatic foam, one hollowed out a bit with a penknife, would work
>well. It would both shield from airflow and provide insulation.
The problem is that an LTZ1000 (or LM399) runs hot enough that most
plastics you find lying around won't stand up to it for very long
(some of them melt almost immediately when you power it up). This is
true even of polycarbonate, which is one of the most durable common
plastics, and is why the original caps were made from polysulfone.
Unfortunately, it also means that replacements may be hard to make by
3D "printing," since the process depends on melting the base material.
Best regards,
Charles
PK
Poul-Henning Kamp
Wed, Jan 28, 2015 7:26 PM
In message <trinity-b86e1035-9d9f-4cd6-b6b7-1d82a5a7a3bb-1422466044261@3capp-gm
x-bs72>, acbern@gmx.de writes:
I've often wondered what would happen if you put one of these
circuits (xtal, vref etc) in a suitable small box, and filled
the box with with aerogel powder:
http://unitednuclear.com/index.php?main_page=product_info&cPath=16_17_69&products_id=89
I'm pretty sure you'd get very stable temperatures, my worry is
that you'd get too high stable temperatures...
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
--------
In message <trinity-b86e1035-9d9f-4cd6-b6b7-1d82a5a7a3bb-1422466044261@3capp-gm
x-bs72>, acbern@gmx.de writes:
I've often wondered what would happen if you put one of these
circuits (xtal, vref etc) in a suitable small box, and filled
the box with with aerogel powder:
http://unitednuclear.com/index.php?main_page=product_info&cPath=16_17_69&products_id=89
I'm pretty sure you'd get very stable temperatures, my worry is
that you'd get too high stable temperatures...
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
DD
Dr. David Kirkby (Kirkby Microwave Ltd)
Wed, Jan 28, 2015 7:36 PM
The problem is that an LTZ1000 (or LM399) runs hot enough that most plastics
you find lying around won't stand up to it for very long (some of them melt
almost immediately when you power it up). This is true even of
polycarbonate, which is one of the most durable common plastics, and is why
the original caps were made from polysulfone.
Unfortunately, it also means that replacements may be hard to make by 3D
"printing," since the process depends on melting the base material.
Best regards,
Charles
Is there any reason this cap is not made of metal? If its purpose is
to restrict airflow by convection, metal will do. Copper sheet can
easily be soldered to make something that would restrict airflow and s
If you want thermal insulation, then PTFE rivited to a metal shield
would provide a plastic that will not melt, and the metal would keep
it in place, as its hard to form a box out of PTFE. It is not an easy
material to glue, but nuts/bolts/rivits will work.
Dave
On 28 January 2015 at 18:56, Charles Steinmetz <csteinmetz@yandex.com> wrote:
> The problem is that an LTZ1000 (or LM399) runs hot enough that most plastics
> you find lying around won't stand up to it for very long (some of them melt
> almost immediately when you power it up). This is true even of
> polycarbonate, which is one of the most durable common plastics, and is why
> the original caps were made from polysulfone.
>
> Unfortunately, it also means that replacements may be hard to make by 3D
> "printing," since the process depends on melting the base material.
>
> Best regards,
>
> Charles
Is there any reason this cap is not made of metal? If its purpose is
to restrict airflow by convection, metal will do. Copper sheet can
easily be soldered to make something that would restrict airflow and s
If you want thermal insulation, then PTFE rivited to a metal shield
would provide a plastic that will not melt, and the metal would keep
it in place, as its hard to form a box out of PTFE. It is not an easy
material to glue, but nuts/bolts/rivits will work.
Dave
JP
John Phillips
Wed, Jan 28, 2015 8:37 PM
I needs to insulate electrical and thermal and metal would not do well.
On Wed, Jan 28, 2015 at 11:36 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
The problem is that an LTZ1000 (or LM399) runs hot enough that most
you find lying around won't stand up to it for very long (some of them
almost immediately when you power it up). This is true even of
polycarbonate, which is one of the most durable common plastics, and is
the original caps were made from polysulfone.
Unfortunately, it also means that replacements may be hard to make by 3D
"printing," since the process depends on melting the base material.
Best regards,
Charles
Is there any reason this cap is not made of metal? If its purpose is
to restrict airflow by convection, metal will do. Copper sheet can
easily be soldered to make something that would restrict airflow and s
If you want thermal insulation, then PTFE rivited to a metal shield
would provide a plastic that will not melt, and the metal would keep
it in place, as its hard to form a box out of PTFE. It is not an easy
material to glue, but nuts/bolts/rivits will work.
Dave
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
I needs to insulate electrical and thermal and metal would not do well.
On Wed, Jan 28, 2015 at 11:36 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
> On 28 January 2015 at 18:56, Charles Steinmetz <csteinmetz@yandex.com>
> wrote:
>
> > The problem is that an LTZ1000 (or LM399) runs hot enough that most
> plastics
> > you find lying around won't stand up to it for very long (some of them
> melt
> > almost immediately when you power it up). This is true even of
> > polycarbonate, which is one of the most durable common plastics, and is
> why
> > the original caps were made from polysulfone.
> >
> > Unfortunately, it also means that replacements may be hard to make by 3D
> > "printing," since the process depends on melting the base material.
> >
> > Best regards,
> >
> > Charles
>
> Is there any reason this cap is not made of metal? If its purpose is
> to restrict airflow by convection, metal will do. Copper sheet can
> easily be soldered to make something that would restrict airflow and s
>
> If you want thermal insulation, then PTFE rivited to a metal shield
> would provide a plastic that will not melt, and the metal would keep
> it in place, as its hard to form a box out of PTFE. It is not an easy
> material to glue, but nuts/bolts/rivits will work.
>
> Dave
> _______________________________________________
> volt-nuts mailing list -- volt-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
--
*John Phillips*
CS
Charles Steinmetz
Wed, Jan 28, 2015 11:06 PM
I've often wondered what would happen if you put one of these
circuits (xtal, vref etc) in a suitable small box, and filled
the box with with aerogel powder:
* * *
I'm pretty sure you'd get very stable temperatures, my worry is
that you'd get too high stable temperatures...
I think over-insulation is a very real worry, given what the web site
says about the thermal insulating properties. The properties they
described seem to be those of a solid block or sheet -- the powder
may not be quite as good -- but still, it seems like you'd be going a
long way toward emulating a dewar, and it is very easy to
over-insulate an oscillator or other circuit with a dewar.
Another possibility is glass microballoons (also called
microspheres), which are just what they sound like. They are a very
common filler for epoxy when a featherweight composite is required.
Either one would probably be kind of messy....
Best regards,
Charles
Poul-Henning wrote:
>I've often wondered what would happen if you put one of these
>circuits (xtal, vref etc) in a suitable small box, and filled
>the box with with aerogel powder:
> * * *
>I'm pretty sure you'd get very stable temperatures, my worry is
>that you'd get too high stable temperatures...
I think over-insulation is a very real worry, given what the web site
says about the thermal insulating properties. The properties they
described seem to be those of a solid block or sheet -- the powder
may not be quite as good -- but still, it seems like you'd be going a
long way toward emulating a dewar, and it is very easy to
over-insulate an oscillator or other circuit with a dewar.
Another possibility is glass microballoons (also called
microspheres), which are just what they sound like. They are a very
common filler for epoxy when a featherweight composite is required.
Either one would probably be kind of messy....
Best regards,
Charles
