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Date
Re: Need info on TO-3 transistor insulator

 

Froggie,
Re float the HS,
I believe HP did this on some of their
Bigger bench/rack (older) power supplies, whoever did the mechanical
designs on these was not the sharpest
tack in the box,, mechanical shocks would dislodge the heatsink and cause all kinds of problems

On Fri, Jun 11, 2021, 1:52 AM Froggie the Gremlin <jonpaul@...> wrote:
Hi, anodized TO-3 oxide films on the insulators were easily punctured, resulting in shorts.

We used kapton and Bergquist TO-3 insulators.

For 220 W suggest,? you bolt direct to your heatsink and float the entire HS.

I have? designed tested and manufactured power magnetics since 1980s, never had to make such a fixture.

So very Interested in exactly what you are testing and the inductor design.

Bon Soir¨¦e

Jon
Re: Meaning of red sticker on equipment

 

Red dots are often indication of defective or repair.
Looking at the photos, I see cracks in the top face plastic, as well as the oxidized BNCs.
This is an indication of poor storage, or mistreatment.
----------------------
Depending upon the cost, you should decide if return and find a better unit is worthwhile.
------------------------
But many pitfalls in ebay returns!
Use the procedure " not as described" so ebay sends you a USPS return label.
Otherwise you will pay for the freight and may not get the ebay refund.

Bon Chance


Jon
Re: Need info on TO-3 transistor insulator

 

¿ªÔÆÌåÓý

Yeah, my rule of thumb is don't count on anodized aluminum being an insulator, and don't count on it being a conductor.? ? And kapton insulators can be punctured by burrs on a heatsink or device flange, so be careful there, too.? Been there, done that.? ? ? ? Jim Ford?



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Froggie the Gremlin <jonpaul@...>
Date: 6/10/21 8:52 PM (GMT-10:00)
Subject: Re: [HP-Agilent-Keysight-equipment] Need info on TO-3 transistor insulator

Hi, anodized TO-3 oxide films on the insulators were easily punctured, resulting in shorts.

We used kapton and Bergquist TO-3 insulators.

For 220 W suggest,? you bolt direct to your heatsink and float the entire HS.

I have? designed tested and manufactured power magnetics since 1980s, never had to make such a fixture.

So very Interested in exactly what you are testing and the inductor design.

Bon Soir¨¦e

Jon
Re: Need info on TO-3 transistor insulator

 

Hi, anodized TO-3 oxide films on the insulators were easily punctured, resulting in shorts.

We used kapton and Bergquist TO-3 insulators.

For 220 W suggest, you bolt direct to your heatsink and float the entire HS.

I have designed tested and manufactured power magnetics since 1980s, never had to make such a fixture.

So very Interested in exactly what you are testing and the inductor design.

Bon Soir¨¦e

Jon
Re: Meaning of red sticker on equipment

 

On 6/10/21 10:58 PM, Matt Huszagh wrote:
Ok, after doing a bit of research, it sounds like it can tarnish if it's
a gold alloy. Does that sound right?

Think it's worth cleaning these with deoxit? There's an amazing
restoration on the eevblog:



The poster does an amazing job of cleaning old BNC connectors. However,
I don't have the mechanical skills of that guy (he's a machinist by
trade, apparently) and I'm nervous to try it on a triaxial connector as
well as these fixture connectors that appear to be quite fragile.
I've read that thread. Amazing and beautiful work.

But honestly, if your concerns are not aesthetic, I'd not worry about
it unless you actually experience trouble with the connectors.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: Meaning of red sticker on equipment

 

Matt Huszagh <huszaghmatt@...> writes:

Are they not gold plated? All of the center conductors appear gold.
Ok, after doing a bit of research, it sounds like it can tarnish if it's
a gold alloy. Does that sound right?

Think it's worth cleaning these with deoxit? There's an amazing
restoration on the eevblog:



The poster does an amazing job of cleaning old BNC connectors. However,
I don't have the mechanical skills of that guy (he's a machinist by
trade, apparently) and I'm nervous to try it on a triaxial connector as
well as these fixture connectors that appear to be quite fragile.

Matt
Re: Meaning of red sticker on equipment

 

¿ªÔÆÌåÓý

Could possibly even be from the eBay seller. 73 ¨C Mike

?

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

?

From: [email protected] <[email protected]> On Behalf Of Ed Breya via groups.io
Sent: Thursday, June 10, 2021 9:20 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Meaning of red sticker on equipment

?

Miscellaneous stickers could mean anything, from a problem, to drawing attention to certain things for the operator, or even that it's been inventoried during asset accounting. I remember many years ago, whenever it was inventory season, accounting would have new recruits do the physical work of finding everything, listing it, and marking it to avoid confusion later. These people were typically totally clueless about what things were, and just needed to find the stuff - we would often find stickers on CRT faces and such afterward.

The black on the connectors is just tarnish on the silver plated parts, and should not affect operation.

Ed

Re: Meaning of red sticker on equipment

 

"Ed Breya via groups.io" <edbreya@...> writes:

Miscellaneous stickers could mean anything, from a problem, to drawing attention to certain things for the operator, or even that it's been inventoried during asset accounting. I remember many years ago, whenever it was inventory season, accounting would have new recruits do the physical work of finding everything, listing it, and marking it to avoid confusion later. These people were typically totally clueless about what things were, and just needed to find the stuff - we would often find stickers on CRT faces and such afterward.
Ok, good to know.

The black on the connectors is just tarnish on the silver plated parts, and should not affect operation.
Are they not gold plated? All of the center conductors appear gold.

Matt
4395A software

 

Shot in the dark -- does anybody have a 4395A Adjustment Program?

I could even pay a reasonable amount for this...

The Keysight Knowledge Base explicitly says:

=== Cut ===
The "Performance Test Program" and the "Adjustment Program" for the 4395A
and 4396B Combination Analyzers are not available for trade sale.
=== Cut ===

No wonder they don't sell it -- they charge $1K for basic calibration and
$1,500+ for calibration with uncertainties. It is more than what a used
working 4395A can be found for...

---
*
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
*
Re: Meaning of red sticker on equipment

 

Miscellaneous stickers could mean anything, from a problem, to drawing attention to certain things for the operator, or even that it's been inventoried during asset accounting. I remember many years ago, whenever it was inventory season, accounting would have new recruits do the physical work of finding everything, listing it, and marking it to avoid confusion later. These people were typically totally clueless about what things were, and just needed to find the stuff - we would often find stickers on CRT faces and such afterward.

The black on the connectors is just tarnish on the silver plated parts, and should not affect operation.

Ed
Meaning of red sticker on equipment

 

Hi,

I received a test fixture for a 4145A today (from Ebay, listed used) and
noticed a little red sticker on the unit that wasn't in the
listing. I've attached a picture. What does this mean?

I've seen a red sticker before on a unit I bought broken, so I sort of
assumed this meant the device was non-functional. Is this correct?

The test fixture has a few broken fingers (image also attached). I'm
less worried about this since I have a direct replacement for it, but
still annoyed.

More concerning is that the center conductor for one of the triaxial
connectors looks very blackened (third image, though unfortunately hard
to make out in the image). Is this likely to impair functionality, and
should I be concerned?

Finally, the center conductors for the BNC connectors look sick
(blackened in the same way as one of the triaxials). This should be
easier to replace.

I did not pay a "for parts or not working" price for this and the
pictures made the unit look ok with the description stating "in very
good condition" (in retrospect I should have asked for better images).

Thoughts? I'm well within my 30 day window so I can return it or ask for
a partial refund.

Thanks
Matt

IMG_0940.JPG
IMG_0941.JPG
IMG_0942.JPG
IMG_0944.JPG

Re: hp 35670A option 1D2 swept sine

 

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Thanks,

Yes I have slowly come to the realisation that all this is stored in U27 on A7. This is I believe a 24Co1 EEPROM.

Thanks for the help.

?

Mark

?

From: [email protected] <[email protected]> On Behalf Of nj902 via groups.io
Sent: Friday, 11 June 2021 3:08 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] hp 35670A option 1D2 swept sine

?

The swept sine is very nice to have.? I paid them $1500 for the option upgrade.

As with the 35665A, when you ordered an option upgrade, they sent you a disk with the code to enable it on your serial number.

The analyzer's serial number and firmware options are stored in EEPROM (U27)

If you can find a suitable 'donor' image, you can replace or reprogram your EEPROM to add all the options.

Re: Need info on TO-3 transistor insulator

 

Thanks Walter,

I did run across that same document, which briefly compares hard anodized with some others, but without specific part numbers. I was hoping to find actual specs for these parts, but it looks like info is indeed sparse. Your mentioning it made me look at the app note again, and more closely. By putting the "datasheet" and the app note info together, I think it will be close enough. The app note describes the hard anodized as 20 mils thick, and so does the datasheet, so that was probably the standard thickness for those things.

According to the app note charts on pages 5 and 6, the hard anodized is superior (but not by all that much) to mica, and quite a bit better than sil-pads of various types, in the TO-3 "greased" configuration. Only BeO and bare (non-insulated) are significantly better. I'll go with about 0.3 deg C/W nominal, for estimating.

I'll need to dissipate about 220 W worst case among three transistors. This is for my inductor test (in conjunction with the HP4276A) fixture project. I was originally going to use some modern big (TO-264 I think) MOSFETs that I have on hand, that are DC-SOA rated, but the shunt drain capacitance is huge, especially running with such low overhead - not good for this sort of thing. I found I have a bunch of nice old-school 2N6283 Darlingtons (TO-3), and decided to go with bipolar. The C-E operating limits and such puts it on par with the MOSFETs overhead-wise, but with about ten times less - and more predictable - capacitance. This is the nonlinear Miller C that I'll be trying to compensate for with some trick circuitry. There's also quite a lot of fixed C due to the insulators. I was quite surprised at how much it can be - I never considered or measured it until this application came up. With mica, I found about 200-300 pF from the TO-3 case to heatsink. Interestingly, the hard anodized landed in the same range.

I'm not too worried about the breakdown voltage - the maximum excursion of the collectors is limited to the -12 V supply, and possibly up to +40 V clamping level for any inductive kickback. Even if an insulator should fail, the collectors are the output of the current source, and would just short to earth ground. If the current setting is in the high (0-20 A) range, the fault tripper will kick it out of the range, to a safe level, to avoid melting any power cords or cables.

The thermal resistance is mostly important for quietness, actually. I have a nice big flow-through setup worked out, and would like to set the fan to a low, constant speed. It's capable of a helluva lot of cooling if I wear earmuffs. The better the transistors connect with the heatsink, the slower I can run it.? I can make it shift up if necessary, but more complicated.

Ed
Re: Off topic - IRF attenuators

 

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Thanks guys.

?

Kind regards

?

Colin

?

From: [email protected] <[email protected]> On Behalf Of george edmonds via groups.io
Sent: Thursday, June 10, 2021 7:48 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Off topic - IRF attenuators

?

For Marconi?

/g/Marconi-Test-Instruments

For IFR

/g/IFR-Monitors

George G6HIG

Re: Off topic - IRF attenuators

 

For Marconi?

/g/Marconi-Test-Instruments

For IFR

/g/IFR-Monitors

George G6HIG
Re: Off topic - IRF attenuators

 

¿ªÔÆÌåÓý

Its originally an Marconi signal generator--please go to the marconi group and you will be helped.

Hardy

?

Fra: [email protected] [mailto:[email protected]] P? vegne af Roy Thistle
Sendt: 10. juni 2021 20:09
Til: [email protected]
Emne: Re: [HP-Agilent-Keysight-equipment] Off topic - IRF attenuators

?

On Thu, Jun 10, 2021 at 06:59 AM, Colin Smithers wrote:

where I should ask

It a sig gen... but the cats on
/g/IFR-Monitors
... they might have some know too.


Virusfri.

Re: Off topic - IRF attenuators

 

On Thu, Jun 10, 2021 at 06:59 AM, Colin Smithers wrote:
where I should ask
It a sig gen... but the cats on
/g/IFR-Monitors
... they might have some know too.
Re: Hp8558b spectral analyzer (2/2)

Bob Stewart
 

You might check the diodes in the first mixer.? Don't disturb the trimmer screws.

Bob


On Thursday, June 10, 2021, 11:03:46 AM CDT, Gerard <kabupos@...> wrote:


hello,

News from the internal attenuator of this 8558B HP
As this is a mechanical attenuator (Action of a rotary button only), I did this little test.
Disconnect in and out attenuator.?it is autonomous now
Sending a sinusoidal signal 10 MHZ with a generator via a resistor of 50 ohm
Oscilloscope measurement input and output.

As I turn the button, the signal drops out (constant input).
The method is not very academic and I am not amused to convert to DB.?I am allergic to all measures in DB (LOL)

I think it works, because it¡¯s a constant decay, even if you only see a few millivolts 3 notches before the end of the rotation. (For only 0.3v input)
I did not want to force too much the signal to the enter?
I think it¡¯s not burned, so I¡¯m gonna look at something else

cdt

Re: Need info on TO-3 transistor insulator

walter shawlee
 

The only info with real specs I found on this topic is an old Motorola/ON App note, AN-1040D, it does discuss these anodized transistor insulators towards the end of the article. you can find it from ON semi here:

https://www.onsemi.com/pub/Collateral/AN1040-D.PDF

I would not be so keen to use these older anodized insulators in actual life, I see zero advantage compared to more
modern techniques, and I doubt the voltage breakdown is as good as even poor film, pads or mica.
all the best,
walter? (walter2 -at- sphere.bc.ca
sphere research corp.
Re: Capturing screenshots on 8934C

w9dkc
 

I have the correct cable. I used it about 8 years ago. It worked. I'm starting to think there may be an issue with the 8924
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