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Re: mailing lists, was Re: [HP-Agilent-Keysight-equipment] Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
On 12/1/24 12:24, Dr. David Kirkby, Kirkby Microwave Ltd wrote:
? ?Groups.io is a commercial vendor of mailing list services.? TheyWhile I generally agree, we would do well to bear in mind why those additional features exist, and remember what happened to groups.io's predecessor, Yahoo Groups. Anyone can serve up mailing lists. Hell, I run a dozen of them from my company's network, no commercial BS involved. Companies like groups.io offer additional stuff to capture users' data and create vendor lock-in situations, in which it's very difficult to migrate away. Then when everyone is using the file archives, the wikis, the databases, etc etc, they start raising their prices. This has been done by every company offering such services, and indeed it has been done by groups.io themselves. And when they shut down, or give users another compelling reason to move en masse, that data can be very difficult to recover in any usable way. Witness the Yahoo Groups disaster. Yes, some of these additional facilities are interesting and useful. They're designed to be. And once you start using one of them, it's easy to start using more and more of them. Then you're stuck. So while I agree that such facilities are useful, I think they should be utilized with great care, backups, and a fallback plan. Corporations typically do not have our interests in mind, and we need to remember that. They are not charities or people working to help us with our craft, they exist to make MO' MONEY MO' MONEY by whatever means possible. Trust them at your peril. -Dave -- Dave McGuire, AK4HZ New Kensington, PA |
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Re: mailing lists, was Re: [HP-Agilent-Keysight-equipment] Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
On Sun, 1 Dec 2024 at 02:51, Dave McGuire via <mcguire=[email protected]> wrote: On 11/30/24 21:27, Dan via wrote: True.?
Groups.io offers FAR more functionality than a mailing list. A mailing list doesn¡¯t offer 30 GB of file storage, a wiki, and a whole host of other features that the group has. Not all features are enabled on this group, as they would serve no useful purpose.? ? ?Many people feel that web forums are the "new" way and mailing lists It¡¯s your personal preference whether you use the other features, but they exist and other people do use them. I feel that they should be encouraged to use them.? Dave? (Group owner)? |
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8350A + 83525A mechanical issues
Hello
In the last months I've been playing with a HP 8350A + 83525A that probably had a uncontrolled impact with something. After replacing a 7426 on CPU board and rebuilding most of the B.West springs with stuff found on taobao, I'm left with mechanical issues. ?Given my noob level I would really appreciate feedback and suggestions from experts.
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The first issue is the plastic lever that operates the power switch (image 1). It broke where the metal pin enters. Glue doesn't seem to be an answer; a 3D printer would probably be the best solution but given the cost I'll just continue plug/unplug the cable.
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Second issue is probably even more complicated. The N connector of the plug in hit something hard and broke the metal fitting inside (image 2). Sorry for the lousy image but haven't decided to take it apart yet given my experience with the reset button of my 5328A (story for another time). This is part of the plug in frame so replacing it means a new plugin very €€€€. Ideas?
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Last question is about adjustments. The last adjustment in the manual is Marker DAC. Although setting the trigger level is quite tricky (seems easier with a scope) the reading I have is indeed 500 and in some moments 400 however full rotations of A4R28 make no differences. This does not sound very good, but more than adequate for hobbyist use
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Thanks in advance for any suggestions for and recommendations
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cheers
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Re: VNA Resonance Methodology
jmr,
I appreciate the offer, but it won't be necessary, thanks all the same. Now I know where I went wrong the dip is readily visible. I just need to take more care with my coil-winding technique in future!
Thanks to all who chipped in with suggestions in this thread; much appreciated. |
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mailing lists, was Re: [HP-Agilent-Keysight-equipment] Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
On 11/30/24 21:27, Dan via groups.io wrote:
Okay, I really appreciate it Dave. ?So what¡¯s the difference really? Do they kind of function the same, but each message and response puts an email in your email account?Yes, pretty much. The first thing to remember is that mailing lists have nothing at all to do with the web, web servers, web sites, or web browsers. It's an email address that you send an email to (by whatever means you access your email), and then that email is re-sent automatically to all the people subscribed to (registered to be recipients of) the mailing list. Groups.io is a commercial vendor of mailing list services. They provide a web interface for list administrators to manage their lists, as well as for people to view archives of past list traffic. In recent years that functionality has been (inadvisably, IMO) extended to include posting messages to the mailing list from the web interface as well. This has blurred the line between mailing lists and web forums, and has resulted in a whole lot of confusion. The primary usage of this and other "groups" is via email, though some people who want to pretend it's a web forum can do so, and it's mostly good enough for that. (though I myself do not have the patience for it; I'm a very busy person) Many people feel that web forums are the "new" way and mailing lists are the "old" way, and while mailing lists are much older (dating back to the 1970s) the reality is that both formats are decades old and it really just boils down to personal preference. -Dave -- Dave McGuire, AK4HZ New Kensington, PA |
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Re: Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
it might actually be better to eliminate this one, I already have a couple responses on the other posting I have, and nothing here, except for you letting me know you saw that I had put two listings on. Thank you
Dan |
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Re: Alignment of HP 412A after rebuild, having trouble with the first step.
I really appreciate it Richard. ?Nothing wrong with the meter, can mechanically zero it no problem with the small adjustment screw. Once the mechanical zero is that the meter is pretty much Dead on with the different DC and AC voltages I fed into it. I was just explaining that when you adjust the home balance it does greatly affect the mechanical zero. So before I did, any alignment work, I set the mechanical zero which it really wasn¡¯t that far off at all. It is the measurements and it looked good. But I wanted to go through the alignment procedure, I did no problem on my 410B. ?Well that¡¯s when I read the first step to look at it on a scope and adjust for the lowest 10 Hz signal. I could pick up and that¡¯s when I saw it. Completely messed up my mechanical zero. Plus my scope was reading signals in the kHz. ? by adjusting the home balance I was able to get the scope read out to be in frequencies much lower, but nowhere near 10 Hz. ?
Dan |
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Re: Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
Okay, I really appreciate it Dave. ?So what¡¯s the difference really? Do they kind of function the same, but each message and response puts an email in your email account?
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Thank you again,
Dan |
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Re: Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
On 11/30/24 18:04, Dan via groups.io wrote:
I apologize, I have a duplicate thread. I didn¡¯t realized the post had to be authorized before being posted. It can be deleted, use this thread for help.No problem. I saw the two messages in the moderator queue and it was pretty clear what happened, so I just put both through not knowing if you'd have a preference as to which one went. Keep in mind, though, that this is not a web forum, it is a mailing list that also has a web interface. -Dave -- Dave McGuire, AK4HZ New Kensington, PA |
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Alignment of HP 412A after rebuild, having trouble with the first step.
Hello all, I am finishing up on a restoration of a HP 412A VTVM. ?It¡¯s quite accurate from the get go after the restoration. ?
I replaced every capacitor minus ceramics, I replaced pretty much every carbon composite resistor with 1% metal film of good quality, installed nos tubes that tested quite strong. ?I¡¯m not sure if I¡¯m doing the hum balance correctly. ?
It says to connect a scope to the amplifier terminals which happen to be on the back of the meter and adjust for minimal 10 hz signal. ? I¡¯m not seeing any 10 hz, only seeing stuff in the kHz.
If I adjust the hum balance pot it does change the waveform seen and it does lower the frequency, but I get nowhere near 10 hz and the frequency is jumping all over the place. ?
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I did also notice that the hum balance adjustment also affects the zero point of the meter fairly greatly. ?After playing around with it I had to zero the meter using the small screw directly below the meter face.
How do I do this correctly? When adjusting hum balance in a tube amplifier I would adjust for lowest noise/hum. Would adjusting for the lowest point where the needle sits on the meter work? Equating that the needle is higher due to noise, this is a total guess here. ? I¡¯m sure there are others that have aligned this meter so I¡¯m hoping for some help.
Thank you,
Dan |
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Trying to go through alignment procedure for HP412A that I rebuilt, having trouble with first step lol
Hello all, I am finishing up on a restoration of a HP 412A VTVM. ?It¡¯s quite accurate from the get go after the restoration. ?
?
I replaced every capacitor minus ceramics, I replaced pretty much every carbon composite resistor with 1% metal film of good quality, installed nos tubes that tested quite strong. ?I¡¯m not sure if I¡¯m doing the hum balance correctly. ?
It says to connect a scope to the amplifier terminals which happen to be on the back of the meter and adjust for minimal 10 hz signal. ? I¡¯m not seeing any 10 hz, only seeing stuff in the kHz.
?
?
If I adjust the hum balance pot it does change the waveform seen and it does lower the frequency, but I get nowhere near 10 hz and the frequency is jumping all over the place. ?
I did also notice that the hum balance adjustment also affects the zero point of the meter fairly greatly. ?After playing around with it I had to zero the meter using the small screw directly below the meter face.
How do I do this correctly? When adjusting hum balance in a tube amplifier I would adjust for lowest noise/hum. Would adjusting for the lowest point where the needle sits on the meter work? Equating that the needle is higher due to noise, this is a total guess here. ? I¡¯m sure there are others that have aligned this meter so I¡¯m hoping for some help.
Thank you,
Dan |
Dave McGuire
Dr. David Kirkby, Kirkby Microwave Ltd
Jinxie
Dan