¿ªÔÆÌåÓý

  1. HP-Agilent-Keysight-Equipment
  2. Messages
Expanded Topics Messages
Date
Re: My $25 "In Poor Shape" 3468A has arrived

 

I did receive a set of those clips, and found it necessary to
solder the 4mm expansion sleeve/banana part to the base of
the plug so it doesn't spin and make poor contact.?
The meter will not zero otherwise.

JimMc

On Thursday, April 4, 2019, 7:59:10 AM PDT, Jeremy Nichols <jn6wfo@...> wrote:


I have a set on order and will report when they arrive.?

Jeremy?


On Wed, Apr 3, 2019 at 11:54 PM Tom Gardner <tggzzz@...> wrote:
I bought some which look identical to that, and they didn't work. I demanded and
eventually got a refund.

The symptom was that on one of the leads, when measuring the resistance from one
4mm plug -> clamp -> 4mm plug, it looked effectively open circuit.

At first I presumed a wire was in place but not soldered properly, but the real
problem was that there was a coating on the clamp's "gold" teeth. Filing the
teeth resolved the problem, with the obvious downside.



On 04/04/19 03:58, Alex wrote:
> My chinese Kelvin test leads finally arrived, and they look & feel very good
> and solid. As usual my 3468A almost reads zero altough still a bit negative
> when I short them out. But I am pretty sure this problem will be solved very
> soon once I get something that is already in the mail.
>
> These cables took and extra week delay because of a post office mess-up on top
> of the several weeks it normally takes to get something from the far East. I
> am very glad I got these. Amazing build quality for only a bit under $9 and
> would highly recommend them to anyone.
>
>




--
4.
Re: My $25 "In Poor Shape" 3468A has arrived

 

I have a set on order and will report when they arrive.?

Jeremy?


On Wed, Apr 3, 2019 at 11:54 PM Tom Gardner <tggzzz@...> wrote:
I bought some which look identical to that, and they didn't work. I demanded and
eventually got a refund.

The symptom was that on one of the leads, when measuring the resistance from one
4mm plug -> clamp -> 4mm plug, it looked effectively open circuit.

At first I presumed a wire was in place but not soldered properly, but the real
problem was that there was a coating on the clamp's "gold" teeth. Filing the
teeth resolved the problem, with the obvious downside.



On 04/04/19 03:58, Alex wrote:
> My chinese Kelvin test leads finally arrived, and they look & feel very good
> and solid. As usual my 3468A almost reads zero altough still a bit negative
> when I short them out. But I am pretty sure this problem will be solved very
> soon once I get something that is already in the mail.
>
> These cables took and extra week delay because of a post office mess-up on top
> of the several weeks it normally takes to get something from the far East. I
> am very glad I got these. Amazing build quality for only a bit under $9 and
> would highly recommend them to anyone.
>
>




--
4.
Re: E7495A/B software

 

On Thu, Apr 4, 2019 at 3:55 AM David C. Partridge <david.partridge@...> wrote:

Attachments may vanish after a while.?


Is this true? I don't think auto-deletes attachments any more than uploaded files or folders. The only mention of deleting attachments on their site is this:?/g/GroupManagersForum/wiki/Deleting%20attachments,%20files%20and%20photos, which describes a rather laborious one-by-one manual process.
?

far better to place something like this in the Files Area in an appropriately named ¡°Folder¡±.


I tend to discover attachments from messages and it's pretty annoying when they're not linked from the discussion. With , each email message has a link to the web view of the discussion, and the web view in turn has the attachment inline or linked from the message.
All round, it seems to me that it's quicker, easier and less error prone to simply email attachments at the list...
Re: E7495A/B software

 

If enough people tell me that this works, I'll ask the moderator to see if we can put it in files.
Although it worked fine for me, I would like some input before putting it into files.
If anyone uses this, please tell me one way or the other.
By the way,how do you get things like this into Files Area? Never done it. Someone please tell me.

About formatting a card for this, The 7495 has a media manager menu that allows you to format a card.
Just put a card into the e7495 any time after boot. You can remove and replace cards anytime.
About the format type:
I think it is Linux ext2, do not know if FAT works but I think if it did it would be FAT12 or 16, do not really know
I would just copy the zipped file onto the card and then unzip it. You can then delete the zipped file from the card, you do not need it and it takes up space.
Wally KC9INK
Re: HP 3325A - Help with photos of Option 002 PCB?

 

¿ªÔÆÌåÓý

I, too, would like some pictures of Option 002.

?

Perhaps they can be posted in the Files section.

?

Thanks.

?

Joe

?

From: [email protected] [mailto:[email protected]] On Behalf Of Jared Cabot
Sent: Thursday, April 04, 2019 5:09 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 3325A - Help with photos of Option 002 PCB?

?

That would be awesome if you could take a few good photos. :)
I have a source on the power connectors, and the signal connectors look to be just RCA style, so they should be easy to find too.

I think I'll just make a copy of the HP design (substituting parts where needed) to make it easy to get up and running.

Re: Schaffner explosions (Re: [HP-Agilent-Keysight-equipment] HP8657B Mains Filter Disaster)

 

¿ªÔÆÌåÓý

From: Chuck Harris
Date: Wed, 03 Apr 2019 13:46:38 PDT

Would a properly sized fuse prevent a fire from happening
if you fired up a hotplate, and placed it in contact with a
curtain?

??? "You cant protect against stupid!"? (Though smoke detectors come close.)


This is a common misconception about fuses and fire protection.
They are pretty good at preventing power cords, wall outlets,
and house wiring, from burning, but do little for problems like
the bad RIFA capacitors.

??? They ARE good at preventing fire, so long as it's a major fault, but yes, in the case of a minor overload, or some other reason why something cooks up to the point of flame, not good.? But you can then argue that it's poor design and or operating practice, that allows that to even come close to happening.

If you look close at the input filter capacitor connections on many PCB's, (where you can get at them) they should have a short narrowing of the trace on one side of the capacitor, as a fusible link in case that capacitor fails.? Or, an overall "on board" correctly rated Fast HRC fuse.? (Many cheap import products don't have that, while also having other doubtful design "features" that can compromise safety.? "Creepage and Clearance" dimensions etc.)

??? In the case of solid state components, then yes, they usually fail first protecting the fuses!? (Seen MANY times within SMPS's, low power wall warts, to 3-phase multi kW types. etc.)

??

The RIFA capacitors will quite happily light up the printed circuit
board, while not blowing a reasonably sized fuse. I have seen them
burn clean through a FR4 circuit board... If it had been G10, there
would have been more than just smoke.

??? Poor design for safety.? What you regard as a "reasonably sized" fuse, is probably too high a rating, and the wrong type for that application. ? We see it in a lot of US products that barely comply with US safety, let alone European rules.? (I work for a US company here in the UK!)? Some US manufactures flout all sorts of product electrical "codes" in practice, if not on paper.? And don't get me started on the poor EMC practices either!? (Clean & Dirty wiring in the same loom, nullifying any EMC filters in those cases!

??

I have seen power transformers that caught fire without blowing the
fuse when the rectifier shorted.

??? Sorry, poor design again, the transformer should be protected with a thermal fuse, ideally of the sort buried in the windings, but at least something attached to the core.? Again, it's a common failing of US sourced transformers when run on 50Hz.? "Signal Transformer Co" parts are particularly prone to self destruct with no other fault present.? (Thankfully, they tend to go open cct on one primary, so I guess they fail safe.)

Did I say I work for a US company, we see it all to often.

Thankfully, big expensive (but very well designed and built) SMPS's are replacing big iron transformer type power supplies.? When (not if) they fail, though often catastrophic in themselves, the overall result is a "safe fail" of the product they are built into, regardless of if, or not, any primary power fuse blows.


Fuses save the house wiring, and the power cords, but not much
else is certain.

??? You save the house wiring, you save the house, especially important I'd have thought in areas where you build with timber frames in a dry climate.

??? Have you ever experienced an auto electrical fire, while driving?? I have, It's not nice!? You can't breathe or see, and that happens in a fraction of a second when the loom fails and no fuse is present, the entire dash/console "goes up" in front of your face.? Luckily I managed to come to a halt and bail out without injury, but only just.?? I also managed to disconnect the battery just in time to prevent total loss of the vehicle.

??? The rewire involved plenty of circuit segregation and a fuse for each circuit and/or function.? No "false blows" in the last 16 years, but at least one potential fire prevented when a fan motor seized.

([OT]? Anyone with a "Series 3" (or older) Land Rover.? Note, that there is no fuse fitted BY DESIGN in the obligatory lighting circuit (but there is a "spare" in the fuse box) while the tail light wires run through "P" clips in the rear toolbox of the tub.? It was one of those (the one single clip without a rubber/plastic protector) that had worn through the wire insulation, that caused the above fire the instant I turned on the exterior lights as it was getting dark.)

Take care.

??? Dave G0WBX.



-- 
Created on and sent from a Unix like PC running and using free and open source software.
::

Re: HP 3325A - Help with photos of Option 002 PCB?

 

That would be awesome if you could take a few good photos. :)
I have a source on the power connectors, and the signal connectors look to be just RCA style, so they should be easy to find too.

I think I'll just make a copy of the HP design (substituting parts where needed) to make it easy to get up and running.
Re: HP 3325A - Help with photos of Option 002 PCB?

 

Hi,

I was recently thinking about the same for my 3325B, but ended up buying a non working 3325A with the option and just transplanted the option. This has the advantage that you get all the accessories, like connecting signal cables and power cable that are otherwise needed if you roll your own board.
I was looking into the possibility of either replicating the original design, there are no special parts there, with maybe of the exception of a dual transistor. Or creating a new design with modern high voltage opamps, which is also not trivial. On the original Opt002 I? measured about 3,5MHz 3db bandwidth, which there are high voltage opamps with this bandwidth, but the slew rate is not sufficient to go for 40V. Of course this is solvable, but I have not yet investigated further.
But if you can wait a couple of days, I can make you detailed photos of the original option module, just need to disassemble the 3325B for that.

Szabolcs


Jared Cabot <jaredcabot@...> ezt ¨ªrta (id?pont: 2019. ¨¢pr. 4., Cs, 11:16):

Hi,

I have just recently picked up a working 3325A Function Generator, and am thinking about building my own Option 002 board (High Voltage output board) to give me 40v output capability.

I had good success building a DC Bias Option 001 board for my 4276A LCZ meter that works great, so I am feeling a little confident I can build my own option board a second time. :D

Does anyone have one of these 3325A machines with the option that they could take a photo of each side of the option board and a photo of how it is connected inside the unit?

That way I can somewhat match the HP design and then connect it properly once it's done.

?

Any help would be greatly appreciated!

Thanks!

Jared
HP 3325A - Help with photos of Option 002 PCB?

 

Hi,

I have just recently picked up a working 3325A Function Generator, and am thinking about building my own Option 002 board (High Voltage output board) to give me 40v output capability.

I had good success building a DC Bias Option 001 board for my 4276A LCZ meter that works great, so I am feeling a little confident I can build my own option board a second time. :D

Does anyone have one of these 3325A machines with the option that they could take a photo of each side of the option board and a photo of how it is connected inside the unit?

That way I can somewhat match the HP design and then connect it properly once it's done.

?

Any help would be greatly appreciated!

Thanks!

Jared
Re: HP 70590A Information wanted part of HP 70000 / MMS

 

70590A H69 is supported from 70900A version 861015 (MEM+ hardware)


.
--------------------------------------------

On Thu, 4/4/19, David & Laura <davidandlaura@...> wrote:

Subject: Re: [HP-Agilent-Keysight-equipment] HP 70590A Information wanted part of HP 70000 / MMS
To: [email protected]
Date: Thursday, April 4, 2019, 4:04 AM

I
believe it is supported in conjunction with a
70900A.
I won¡¯t have
access to a large-format scanner for a month or so, so I
can¡¯t scan the schematics. But I have scanned and will
send you the module manual via direct e-mail.
Thanks,
David
SlikVE7FIM
On Wed, Apr 3,
2019 at 3:09 AM Paul Bicknell <paul@...>
wrote:



















Hi Dave


?

Thank
you for your E mail from other E
mails it appears this item is not supported by the normal
70900 local oscillators


?

So only
fit to stripe down for parts


?

Could
you post the clip on a site? either
this one or the? HP 700000 site alternatively send it to me
and I will post it
for you

?

Regards
Paul Bicknell









From:
[email protected]
[mailto:[email protected]]
On Behalf Of
David & Laura

Sent: 03 April
2019 07:55

To: [email protected]

Subject: Re:
[HP-Agilent-Keysight-equipment] HP 70590A Information wanted
part of HP 70000 /
MMS



?



I have the service
manual and the CLIP for this module. Let me know if
you have any specific
questions.





?





Thanks,





?





David
Slik





VE7FIM







?





On Mon, Apr 1, 2019
at 12:54 PM Paul Bicknell <paul@...>
wrote:





Hi

I totally agree with you value is in

The rear connector and any relay it might have? ??20
max



-----Original Message-----

From: [email protected]

[mailto:[email protected]]
On Behalf Of jfphp via

Groups.Io

Sent: 01 April 2019 11:37

To: [email protected]

Subject: Re: [HP-Agilent-Keysight-equipment] HP 70590A
Information wanted

part of HP 70000 / MMS



The 70590A is useless, except you have the military
softwares from Air Force

or Navy dedicated to some gear (F18...) but they need a lot
of non HP plug

ins (Comstron, Tern Technology...) under ITAR regulations.
It is not used by

the various MMS cal and repair softwares. It? is 1? worth.
You can only

dismantle it and get the rear connector as te first step to
build an

extender (not easy !)..

--------------------------------------------

On Mon, 4/1/19, Paul Bicknell <paul@...>
wrote:



?Subject: Re: [HP-Agilent-Keysight-equipment] HP 70590A
Information wanted

part of HP 70000 / MMS

?To: [email protected]

?Date: Monday, April 1, 2019, 12:35 AM



?Hi I have spoken to the UK

?supplier I am due to visit him this week but



?I don¡¯t think he believed me

?when I told him I had only found 7 independent

?users of? HP 70000 equipment in the
UK and

?that a lot? of people stay away

?from it as

?they do not understand how it all slots together



?The problem is a lot look at

?the equipment rate book and assume that is the

?price



?Still

?looking for? Receiver personality software





?-----Original

?Message-----

?From: [email protected]

?[mailto:[email protected]]

?On Behalf Of Harvey White

?Sent: 31 March

?2019 22:59

?To: [email protected]

?Subject: Re: [HP-Agilent-Keysight-equipment] HP

?70590A Information wanted

?part of HP 70000 /

?MMS



?On Sun, 31 Mar 2019

?00:31:55 -0700, you wrote:



?>Hi Paul,

?>

?>"The HP 70590A Options H69 and H72

?TMAs (Test Module Adapters) are MATE

?modules

?for HP 70000 Series spectrum analyzers. The modules

?translate CIIL

?(control intermediate

?interface language) into the HP 70000 Series native

?code. Option H69 modules provide a calibration

?switch signal at the rear

?panel. Option H72

?modules switch the RF and Calibrator signals to the

?analyzer's RF input."

?>

?>See

?>

?>I'm guessing you

?are wondering why a UK
eBay seller thinks he might get up

?to ?1000 for one!



?Does anyone still use MATE?? I worked on a

?runner up to that program a

?long while

?ago... ("our" proposal wasn't
accepted)....



?Did some 488 bus programming

?using a TMS9914 controller run by an

?8088.



?Programmed in PLM-86.



?Don't really know where it went, may have

?been a wildly popular

?standard at the

?time.



?Historical note:



?The US DOD was getting tired

?of all the different instruments used in

?depot level (not flightline, since most of that

?was very custom...)

?speaking a different

?language, per the manufacturer....



?So they had a competition to see who could come

?up with a decent

?language (and it had a

?whole lot of "human factors" concepts thrown

?in, since it was somehow supposed to interface

?to something portable,

?or at least,

?that's what I remember...



?The company I worked for at the time lost.?

?Never quite sure why,

?didn't really

?understand some of the "they expect us to do it
this

?way

?so we will.... thinking"



?but the concept of CIIL was to

?be that all the instruments were to

?speak a

?common language, and that language was to be a
replacement

?for

?the existing instrument languages.



?Lots of money was dumped into

?the concept.



?Harvey





?>

?>Regards,

?>Steve

?>

?>















?-----

?No virus found in this

?message.

?Checked by AVG - www.avg.com

?Version: 2016.0.8048 / Virus Database:

?4793/15884 - Release Date: 08/14/18

?Internal

?Virus Database is out of date.





















-----

No virus found in this message.

Checked by AVG - www.avg.com

Version: 2016.0.8048 / Virus Database: 4793/15884 - Release
Date: 08/14/18

Internal Virus Database is out of date.





















No virus found in
this message.

Checked by AVG - www.avg.com

Version: 2016.0.8048 / Virus Database: 4793/15884 - Release
Date: 08/14/18

Internal Virus Database is out of
date.
Re: E7495A/B software

 

¿ªÔÆÌåÓý

Attachments may vanish after a while.? far better to place something like this in the Files Area in an appropriately named ¡°Folder¡±.

?

David

?

From: [email protected] [mailto:[email protected]] On Behalf Of wallydoc via Groups.Io
Sent: 04 April 2019 04:46
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] E7495A/B software

?

Let us hope this file is not too big
This is the entire Full625 upgrade with the freq/time GPS patch already done
Just unzip and put it on a PCMCIA or CF card and boot the e7495
If anyone tries this please tell me if they have any problems
It worked just fine for me

Attachments:
Re: My $25 "In Poor Shape" 3468A has arrived

 

I bought some which look identical to that, and they didn't work. I demanded and eventually got a refund.

The symptom was that on one of the leads, when measuring the resistance from one 4mm plug -> clamp -> 4mm plug, it looked effectively open circuit.

At first I presumed a wire was in place but not soldered properly, but the real problem was that there was a coating on the clamp's "gold" teeth. Filing the teeth resolved the problem, with the obvious downside.

On 04/04/19 03:58, Alex wrote:
My chinese Kelvin test leads finally arrived, and they look & feel very good and solid. As usual my 3468A almost reads zero altough still a bit negative when I short them out. But I am pretty sure this problem will be solved very soon once I get something that is already in the mail.

These cables took and extra week delay because of a post office mess-up on top of the several weeks it normally takes to get something from the far East. I am very glad I got these. Amazing build quality for only a bit under $9 and would highly recommend them to anyone.
Re: E7495A/B software

 

On Apr 4, 2019, at 05:46, wallydoc via Groups.Io <wallydoc@...> wrote:

Just unzip and put it on a PCMCIA or CF card and boot the e7495
¡°Put it¡± as in make a FAT32 file system on the card and load the files on it?

Gr¨¹?e, Carsten
Re: HP 8720D - Debugging story

 

Here is some CPU fan information. The same processor board is used in the 8720ES where the fan is:

SUNON
KDE0504PEB2-8
5V dc / 0.4W

The fan and heat sink on the 8720D may be different, so this information may or may not not apply to your instrument.

Vladan
Re: E7495A/B software

 

Let us hope this file is not too big
This is the entire Full625 upgrade with the freq/time GPS patch already done
Just unzip and put it on a PCMCIA or CF card and boot the e7495
If anyone tries this please tell me if they have any problems
It worked just fine for me

PCMCIA.7z
PCMCIA.7z

Re: HP 70590A Information wanted part of HP 70000 / MMS

 

I believe it is supported in conjunction with a 70900A.

I won¡¯t have access to a large-format scanner for a month or so, so I can¡¯t scan the schematics. But I have scanned and will send you the module manual via direct e-mail.

Thanks,

David Slik
VE7FIM

On Wed, Apr 3, 2019 at 3:09 AM Paul Bicknell <paul@...> wrote:

Hi Dave

?

Thank you for your E mail from other E mails it appears this item is not supported by the normal 70900 local oscillators

?

So only fit to stripe down for parts

?

Could you post the clip on a site? either this one or the? HP 700000 site alternatively send it to me and I will post it for you

?

Regards Paul Bicknell

From: [email protected] [mailto:[email protected]] On Behalf Of David & Laura
Sent: 03 April 2019 07:55
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 70590A Information wanted part of HP 70000 / MMS

?

I have the service manual and the CLIP for this module. Let me know if you have any specific questions.

?

Thanks,

?

David Slik

VE7FIM

?

On Mon, Apr 1, 2019 at 12:54 PM Paul Bicknell <paul@...> wrote:

Hi
I totally agree with you value is in
The rear connector and any relay it might have? ??20 max

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of jfphp via
Groups.Io
Sent: 01 April 2019 11:37
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 70590A Information wanted
part of HP 70000 / MMS

The 70590A is useless, except you have the military softwares from Air Force
or Navy dedicated to some gear (F18...) but they need a lot of non HP plug
ins (Comstron, Tern Technology...) under ITAR regulations. It is not used by
the various MMS cal and repair softwares. It? is 1? worth. You can only
dismantle it and get the rear connector as te first step to build an
extender (not easy !)..
--------------------------------------------
On Mon, 4/1/19, Paul Bicknell <paul@...> wrote:

?Subject: Re: [HP-Agilent-Keysight-equipment] HP 70590A Information wanted
part of HP 70000 / MMS
?To: [email protected]
?Date: Monday, April 1, 2019, 12:35 AM

?Hi I have spoken to the UK
?supplier I am due to visit him this week but

?I don¡¯t think he believed me
?when I told him I had only found 7 independent
?users of? HP 70000 equipment in the UK and
?that a lot? of people stay away
?from it as
?they do not understand how it all slots together

?The problem is a lot look at
?the equipment rate book and assume that is the
?price

?Still
?looking for? Receiver personality software


?-----Original
?Message-----
?From: [email protected]
?[mailto:[email protected]]
?On Behalf Of Harvey White
?Sent: 31 March
?2019 22:59
?To: [email protected]
?Subject: Re: [HP-Agilent-Keysight-equipment] HP
?70590A Information wanted
?part of HP 70000 /
?MMS

?On Sun, 31 Mar 2019
?00:31:55 -0700, you wrote:

?>Hi Paul,
?>
?>"The HP 70590A Options H69 and H72
?TMAs (Test Module Adapters) are MATE
?modules
?for HP 70000 Series spectrum analyzers. The modules
?translate CIIL
?(control intermediate
?interface language) into the HP 70000 Series native
?code. Option H69 modules provide a calibration
?switch signal at the rear
?panel. Option H72
?modules switch the RF and Calibrator signals to the
?analyzer's RF input."
?>
?>See
?>
?>I'm guessing you
?are wondering why a UK eBay seller thinks he might get up
?to ?1000 for one!

?Does anyone still use MATE?? I worked on a
?runner up to that program a
?long while
?ago... ("our" proposal wasn't accepted)....

?Did some 488 bus programming
?using a TMS9914 controller run by an
?8088.

?Programmed in PLM-86.

?Don't really know where it went, may have
?been a wildly popular
?standard at the
?time.

?Historical note:

?The US DOD was getting tired
?of all the different instruments used in
?depot level (not flightline, since most of that
?was very custom...)
?speaking a different
?language, per the manufacturer....

?So they had a competition to see who could come
?up with a decent
?language (and it had a
?whole lot of "human factors" concepts thrown
?in, since it was somehow supposed to interface
?to something portable,
?or at least,
?that's what I remember...

?The company I worked for at the time lost.?
?Never quite sure why,
?didn't really
?understand some of the "they expect us to do it this
?way
?so we will.... thinking"

?but the concept of CIIL was to
?be that all the instruments were to
?speak a
?common language, and that language was to be a replacement
?for
?the existing instrument languages.

?Lots of money was dumped into
?the concept.

?Harvey


?>
?>Regards,
?>Steve
?>
?>







?-----
?No virus found in this
?message.
?Checked by AVG -
?Version: 2016.0.8048 / Virus Database:
?4793/15884 - Release Date: 08/14/18
?Internal
?Virus Database is out of date.










-----
No virus found in this message.
Checked by AVG -
Version: 2016.0.8048 / Virus Database: 4793/15884 - Release Date: 08/14/18
Internal Virus Database is out of date.




No virus found in this message.
Checked by AVG -
Version: 2016.0.8048 / Virus Database: 4793/15884 - Release Date: 08/14/18
Internal Virus Database is out of date.
Re: My $25 "In Poor Shape" 3468A has arrived

 

My chinese Kelvin test leads finally arrived, and they look & feel very good and solid. As usual my 3468A almost reads zero altough still a bit negative when I short them out. But I am pretty sure this problem will be solved very soon once I get something that is already in the mail.

These cables took and extra week delay because of a post office mess-up on top of the several weeks it normally takes to get something from the far East. I am very glad I got these. Amazing build quality for only a bit under $9 and would highly recommend them to anyone.

https://www.ebay.com/itm/111839980450
E7495 Full625 upgrade with time/freq patch

 

I have put together a zipped file from the current Full625 upgrade
I have applied the well known patch to the zipped 625 file to make the GPS freq/time feature work.
It goes on a PCMCIA or CF card used for updates to the E7495
If anyone wants a copy I would be happy to send one.
Wally KC9INK
Re: Schaffner explosions (Re: [HP-Agilent-Keysight-equipment] HP8657B Mains Filter Disaster)

 

I have a couple of HP 8443A tracking generators. I purchased a smoked unit for spares - the transformer had gone into meltdown.

When the display (nixie tube) on one of my tracking generators quit, I started troubleshooting it, until I laid my hand down on the transformer, and burned my hand. The high voltage rectifiers for the nixie tubes had shorted. The shorted winding drew enough current to toast the transformer, but not enough to blow the fuse. Fortunately I caught it before that transformer destroyed itself.

Perhaps they should have fused that winding.

Gary Appel

-----Original Message-----
From: Chuck Harris
Sent: Wednesday, April 03, 2019 10:46 AM
To: [email protected]
Subject: Re: Schaffner explosions (Re: [HP-Agilent-Keysight-equipment] HP8657B Mains Filter Disaster)

Would a properly sized fuse prevent a fire from happening
if you fired up a hotplate, and placed it in contact with a
curtain?

This is a common misconception about fuses and fire protection.
They are pretty good at preventing power cords, wall outlets,
and house wiring, from burning, but do little for problems like
the bad RIFA capacitors.

The RIFA capacitors will quite happily light up the printed circuit
board, while not blowing a reasonably sized fuse. I have seen them
burn clean through a FR4 circuit board... If it had been G10, there
would have been more than just smoke.

I have seen power transformers that caught fire without blowing the
fuse when the rectifier shorted.

Fuses save the house wiring, and the power cords, but not much
else is certain.

-Chuck Harris
Re: Schaffner explosions (Re: [HP-Agilent-Keysight-equipment] HP8657B Mains Filter Disaster)

 

¿ªÔÆÌåÓý

And if you¡¯re talking about HP equipment, we¡¯ve found the engineers at HP did a great job of designing circuits that happily protect the fuse.?

Regards,

?

Stephen Hanselman

Datagate Systems, LLC

3107 North Deer Run Road #24

Carson City, Nevada, 89701

(775) 882-5117?office

(775) 720-6020?mobile

s.hanselman@...

a Service Disabled, Veteran Owned Small Business

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On Apr 3, 2019, at 13:46, Chuck Harris <cfharris@...> wrote:

Would a properly sized fuse prevent a fire from happening
if you fired up a hotplate, and placed it in contact with a
curtain?

This is a common misconception about fuses and fire protection.
They are pretty good at preventing power cords, wall outlets,
and house wiring, from burning, but do little for problems like
the bad RIFA capacitors.

The RIFA capacitors will quite happily light up the printed circuit
board, while not blowing a reasonably sized fuse. ?I have seen them
burn clean through a FR4 circuit board... If it had been G10, there
would have been more than just smoke.

I have seen power transformers that caught fire without blowing the
fuse when the rectifier shorted.

Fuses save the house wiring, and the power cords, but not much
else is certain.

-Chuck Harris

Dave_G0WBX via Groups.Io wrote:
So don¡¯t rush out replacing all your 250 V nominal equipment (which will
be almost all of your equipment), but do rush out to get rid of the
crazing 1980s' RIFA capacitors (inside a golden clear plastic blob with
lots of cracks) that we are talking about, even when they are inside a
Schaffner line filter.

------------------------------------------------------------------------

Cant help thinking that a power lead with a correctly rated fuse in the
plug will reduce the damage, and certainly the fire risk.

For the non UK readers, we have HRC fuse cartridges in our power lead
plugs, that go into the wall socket. ?Saves a lot of embarrassment
sometimes, unless you get it very wrong...

Might not stop the "Bang"! ?But sure reduces the fire risk.

Regards.

Dave B.
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