Re: Testing dummy loads with a VNA
I do actually have the storage normalizer for this VNA. But I have no idea what it's for or what it does.
I don't want to go down the route of a newer instrument. With gear of this vintage I can keep them alive and fix them up when they go wrong. Anything post-SMT on the other hand - forget it!
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Re: HP1700 Series Rear Cord Wrap Feet
Hi,
I had the same problem with a Tek 465 scope. I found some NOS ones that were sealed in their original bags, but the problem was that them disintegrated the same way. Rubber, some plastics and even carbon composition resistors age regardless they are installed or stored. The solution is to replace them with something different that could make the same function or have them 3D printed.
Regards,
Ignacio EB4APL
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El 09/03/2020 a las 1:59, Sam Reaves escribi¨®: I have a virtually mint HP1740A that was willed to me 30 years ago. I just took it down off the shelf and all 4 cord wrap feet disintegrated. Does anyone have a set or know where I can find them? eBay turns up nothing.
Thanks,
Sam
W3OHM
--
El software de antivirus Avast ha analizado este correo electr¨®nico en busca de virus.
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Re: Testing dummy loads with a VNA
A storage - normalizer would also be a good addition to your 8754A.
However, between the cost of the test set and a normalizer, you might be approaching the cost of moving up a notch or two - say to an early 8753 or maybe one of the 8711/12/13/14 series.
You might be able to sell the 8754A to get a little seed cash to get the process started.? A newer instrument will have a lot of attractive features - greater dynamic range, calibration capability, digital trace storage, hard copy output capability, connection to John Miles software, etc.
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HP1700 Series Rear Cord Wrap Feet
I have a virtually mint HP1740A that was willed to me 30 years ago. I just took it down off the shelf and all 4 cord wrap feet disintegrated. Does anyone have a set or know where I can find them? eBay turns up nothing.
Thanks,
Sam
W3OHM
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So, to finish the story, I purchased for $10 a NOS Sony drive model MP-F17W-20 (same mechanics and power control, different controller board), transplanted the 8751A original floppy controller board to the new floppy drive (fits perfectly), works as good as new.
I took a quick look and it appears to me that the MP-F17W-20 controller board can be configured to generate the FD_CHGRST signal via soldering jumpers, but I didn't bother to investigate further. By default, pin 1 is grounded.
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Re: Testing dummy loads with a VNA
Test port cables is a good idea.
But calibration kits...the 8754A doesn't do calibration.
But if he gets bitten by that bug, he'll have another VNA soon! B-)
-Dave
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On 3/8/20 8:34 PM, bownes wrote:
Test port cables and calibration kits to match.?
Welcome to the insanity!
On Mar 8, 2020, at 20:10, Jinxie <paul666@...> wrote:
?Yeah, but I don't like the Nanovna type stuff; it's not a/proper/ VNA
in my view. How about I buy the matching S-parameter test set for my
VNA? I've been <mailto:I@ve> offered one for USD450 Would that solve
all my problems? And is there anything else I might need in the future?
--
Dave McGuire, AK4HZ
New Kensington, PA
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Re: Testing dummy loads with a VNA
On 3/8/20 8:10 PM, Jinxie wrote: Yeah, but I don't like the Nanovna type stuff; it's not a/proper/ VNA in
my view. How about I buy the matching S-parameter test set for my VNA?
I've been offered one for USD450 Would that solve all my
problems? And is there anything else I might need in the future? $450 seems a bit steep, but admittedly I've not been watching that market. It would certainly give you good functionality, including the specific functionality that you need for the task at hand. I can't help but think you should be able to get away a good bit cheaper than that, but I could be wrong. The only other thing you might want is a calibration kit, but as the 8754A has no automated correction capability, it would be of limited use there. Our own Dave Kirkby makes and sells decent calibration kits at good prices. I agree about the NanoVNA. I did pick one up recently, though...it was on sale, and I want to put it next to my HP 8510C for some side-by-side comparisons. For what it is (a hobbyist toy) it is surprisingly capable and a very nice piece of work. But a piece of lab equipment "it ain't". -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Testing dummy loads with a VNA
Test port cables and calibration kits to match.?
Welcome to the insanity!
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On Mar 8, 2020, at 20:10, Jinxie <paul666@...> wrote:
?Yeah, but I don't like the Nanovna type stuff; it's not a proper VNA in my view. How about I buy the matching S-parameter test set for my VNA? I've been offered one for USD450 Would that solve all my problems? And is there anything else I might need in the future?
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Re: Testing dummy loads with a VNA
Yeah, but I don't like the Nanovna type stuff; it's not a proper VNA in my view. How about I buy the matching S-parameter test set for my VNA? I've been offered one for USD450 Would that solve all my problems? And is there anything else I might need in the future?
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Re: Testing dummy loads with a VNA
On 3/8/20 2:09 PM, David C wrote: You deliberately mis quoted what I said and changed it to:
"the
assertion that they are "intended" to only do thru measurements is
false. Very, very false."
You deliberately took my statement out of context to contradict , censor
and bully
Wont work
I did not say "only"
You invented that. My mistake; it was not a verbatim quote. But the gist of my statement remains; your assertion that "VNAs are intended to do "thru' measurments" (I even included your careless mismatched quotes and original spelling error!) is still false. PS youre off topic attacking the messenger and not responding to OP. I did, in fact, respond to the OP with what I hoped was useful advice to get his job done. Now about that "inventing".. Thats not how we conduct ourselves on the Internet. As if you'd know? Shall we compare net creds? I'd not recommend it. Drop it. Now. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: 693B sweep oscillator restoration
On 3/8/20 2:22 PM, David C wrote: Moderator, where are you? Here's one! I'm wearing my moderator hat, and I'm telling you that you're officially on thin ice. Tone it down and speak respectfully. And for heaven's sake, PLEASE start checking your facts. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: HP 8662A Verification Tape (08662-10001)
On 3/8/20 12:47 PM, Wolfgang Schraml wrote: I got my hands on an 8662A verification tape. I posted the
booklet/manual that came with it in the files section
(/g/HP-Agilent-Keysight-equipment/files/8662A).
I do not have the 9825 controller to read the tape. It may not be
readable at all due to age. From the outside, it appears to be unused.
Anyways - if anyone has the means to read the tape, please let me know
and I will send it to you (US preferred to limit shipping expense). The
only ask I have is - if feasible - to post the contents/files in this
forum. I do not know whether these programs are stored in a binary
format that will only work for a 9825 or in a higher-level programming
language that could be converted to a different platform (e.g. HP Basic
on HP9000/300). Wow, it would be really good if this is able to be saved! -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Testing dummy loads with a VNA
Jinxie,
As others have noted, you will need at least a splitter and a directional coupler.? I gather you are using an 8754a: It does not have software correction of the test setup, so I think you will be limited to the inherent performance of the directional coupler, particularly its directionality.? Later VNAs like the 8753 series can use an open-short-load calibration to correct these hardware errors.? If you are willing to consider a non-HP solution, you might consider just buying a NanoVNA for about $50.? They work pretty well to 900MHz, and acceptably well for evaluating dummy loads (not lab standards) to 1.5GHz.? ?It has a built in test set and usually comes with open, short and load standards for SMA.? You will need appropriate cabling (and perhaps standards) for the type of connectors your dummy loads use.
--John Gord
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Re: Transistor equivalents
There's also one of each controlling the cal signal - A5Q4 and A5Q5 - and my cal signal is dead.
2N3904/2N3906 certainly seem like a good idea.
Thanks.
If I spotted the right parts in the manual, they are in the "220 Hz Multivibrator".
I would try pretty much whatever you have on hand, such as 2N3904 and 2N3906.
If they're not already socketed, consider installing plug-in socket pins, such as the 'machined' type of pins found in the better IC sockets.
Pete
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Re: Transistor equivalents
If I spotted the right parts in the manual, they are in the "220 Hz Multivibrator".
I would try pretty much whatever you have on hand, such as 2N3904 and 2N3906.
If they're not already socketed, consider installing plug-in socket pins, such as the 'machined' type of pins found in the better IC sockets.
Pete
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Re: HP 3456A Problem Solved
Recently i found the same problem with two HP 3437A system voltmeters that we have. After one of them showed occasional digital errors (e.g. failure of display multiplexer) i looked inside. While the power supply generated 4.9 V at 1.5 A, some corners of the digital board received only 4.73 V or so, with a large part of the loss along the ground network. I just added two wires (Gnd and +5V) from one corner to the opposite one as redundant connection and the losses are less than 20 or 30 mV now. The faults are gone.
The digital boards of that time had very few buffer caps. In the 3437A i measured up to 1 Vpp noise on the +5 V net. When looking at the 3456A digital boards (especially those with CMOS logic) i am missing buffer caps that are so common nowadays, especially near the isolation interface digital receivers.
Regards, Dieter
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I'm looking for equivalents for:
1853-0459 and 1854-0810
They seem to be fairly generic 40V VCEO 625mW TO92 transistors.? Used in the 438A power meter.
Thanks, Orin.
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Re: HP 3456A Problem Solved
I think they may be other places, but a web search shows them from this site:
Some links on that page point to the service note files:
As an update, with the boards removed, I took a pair of needle-nose pliers and very gently rotated the ground lugs, every so slightly (just enough to see movement) around each rivet. The resistance appeared to drop to a consistent value for all ground lugs (primarily the lead resistances). I reassembled the boards and when I powered it up, it worked. I measured the +5V at the CPU I measured yesterday and it was back up to 5V as well as the other 5V test points on the other boards.
I'm not convinced that's a very reliable "fix" and still plan to replace the rivets but did find it interesting.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "garp6" <hrgerson@...>
To: [email protected]
Sent: Sunday, March 8, 2020 3:11:44 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 3456A Problem Solved
hi Barry,
Can you post .pdf's of the Service Notes for this ?
thank you,
rick
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Re: 693B sweep oscillator restoration
Hello, please, let us be fair to the two contestants. As my AirBNB hostess pointed out, it is the world woman's day today. So, please, let us all join the two heroes in connecting to our inner feminine side. Seriously: this makes me understand why the Danaher mailing list is moderated so strictly. I will, right now, go out and grab a cigar and light up in the ice cold western German winter. If I get I'll, it is all your fault.
With best regards Tam HANNA (emailing on a BlackBerry PRIV) Enjoy electronics? Join 14k other followers by visiting the Crazy Electronics Lab at Am 8. M?rz 2020 21:51:46 MEZ schrieb Chuck Harris <cfharris@...>:
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Dave C,
Do you have any idea where you are posting?
This is not a paid industry discussion group, but rather a
bunch of people with varied experience that like HP equipment.
Some of us are engineers, with 40+ years of work experience,
and others are hobbyists that have little or no formal
electronics training. The only things we all have in common
is we like this stuff, and we are here.
Anyone thinking that a very, very old sweep oscillator, like
the 693B is going to be used in a professional R&D lab is, in
my belief, delusional.
If you want to help, help. But please, please, leave the chip
on your shoulder stuffed in some closet, far, far away.
If you want to talk about what is really bothering you, feel
free to contact me off group.
-Chuck Harris
David C wrote:
Pete, understood, but your response is not to OP as is proper on a Forum, and technically inaccurate
For a reference, youre referring to personal opinion. I refer to 30 plus years of working on more gear than youve seen in 10 lifetimes.
Electrolytics are SEALED, the local RH has nothing to do with cap life. "Dry out" is not moisture, its electrolyte leakage
Further,? your advice WAITS till a capacitor or other component fails to then chase the fault down. Thats fine for an old stereo, but
not for high end test equipment.
The Context of OPS comment was to bring back to life an old piece of high end test equipment. This is not hobby level work.
Your approach of waiting till a part fails invites disaster...which apparently you dont have as much experience in as do I with 30 years of doing it.
Pete, what happens when an electrolytic on the output of a pass regulator breaks down and shorts the regulator?
Your advice on the resistor on the scope is totally wrong. Realize you are making wildly overgeneralized statements on apiece of gear you know nothing abotu
Facts are, the resistor does NOT get hot. I checked it with an IR thermometer. You statement to use a buck transformer is false, a XFMR wont physically fit.
The assertion that the resistor doesnt regulate is false also, NEITHER DOES THE TRANSFORMER. Pete, where do? you buy Magic Transformers that can regulate voltage?
The on board voltage regulators regulate and the resistor is not relevant.
Sory, youre lecturing an experienced test bench rider and R& D engineer...that attempt at lecturing was a terrible failure as you know nothing about the topics youre lecturing on
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Power Transformer needed for HP1220A (PN 9100-3436)
Greetings all,
I have a HP 1220A scope that needs a new power transformer (HP Part Number 9100-3436). I bought a junker basket case HP1222A at a hamfest for parts unfortunately it uses a totally different power transformer.
Thank you and 73,
Sam Reaves
W3OHM
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Jinxie
Sam Reaves
Dave McGuire
bownes
saipan59 (Pete)