Re: HP-3456A - Question Regarding Resistance Measurement
The following experiment could be interesting:
1. get whatever resistors in the 5-10M range you have so they sum up to approx. 100M.
2. measure resistance of each of the resisitors and sum up the results.
3. measure resistance of all the resistors connected in series... and tell us what you found out.
cheers
Martin
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Hi,
As far as I know, the 8640B has a 3 phase motor for the fan, and one of the power supply boards contains the driver and speed regulator circuits for it. Unless, of course in your unit it has already been replaced by something else.
Szabolcs
Henry Newton < EequalsIR@...> ezt ¨ªrta (id?pont: 2020. okt. 12., H, 23:04):
Hello all,
I've just ordered the brass gears from the eBay fellow in India.? Many thanks to all who presented the gear information.
While waiting, I need to replace my noisy fan in my 8640B.?
From the red & black leads going to a nearby board, it appears it is a 5V fan.? My fan has a black colored motor.
Any ideas on the CFM?? Or a fan source?
Thanks
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Re: UNIX files and dd, Re: [HP-Agilent-Keysight-equipment] Agilent 54831M
On 10/13/20 2:20 AM, Manuel Presnitz wrote: I really enjoyed reading your introduction to the Un*x-/dd-World, Dave. I have just two remarks, you may call it nit picking, but maybe worth mentioning for newcomers:
- The dot does have a special meaning in file names, but only at the beginnng of a file name: all files starting with a dot are hidden files, e.g. ".bashrc" Greetings Manuel, I acknowledge your nitpicking and respond with a bigger nitpicking: The leading dot making the file "hidden" is a convention of usage, and is not handled by the filesystem or the core of the OS (the kernel) itself in any way. It is interpreted and treated that way by the "ls" program, which lists a directory. When a program opens a directory (via the OS system calls) and walks down the list of files it contains, they will all be present, with or without leading dots. The "ls" program does this, and looks for the dots, and doesn't print those entries by default. This can be overridden via command line option "-a", for "all files". Nice try, though. ;) - I think the default block size of dd is "1b", which stands for "1 block" and equals to 512 bytes. This hints a the usual usage of dd with socalled block devices like floppy, hard or optical disks. You are absolutely correct about this one, though; the default block size is in fact 512 bytes. I blame the late hour and the soldering fumes, thank you for the correction! I always explicitly specify a blocksize, so I rarely think about it. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: UNIX files and dd, Re: [HP-Agilent-Keysight-equipment] Agilent 54831M
I really enjoyed reading your introduction to the Un*x-/dd-World, Dave. I have just two remarks, you may call it nit picking, but maybe worth mentioning for newcomers: - The dot does have a special meaning in file names, but only at the beginnng of a file name: all files starting with a dot are hidden files, e.g. ".bashrc" - I think the default block size of dd is "1b", which stands for "1 block" and equals to 512 bytes. This hints a the usual usage of dd with socalled block devices like floppy, hard or optical disks. Best regards, Manuel, DO1MPY. On Tuesday, 13 October 2020, Dave McGuire wrote: First, it's important not to overcomplicate things. From your
statements I assume you're coming from the Windows world. (...)
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Re: UNIX files and dd, Re: [HP-Agilent-Keysight-equipment] Agilent 54831M
On 10/13/20 12:44 AM, Sam Reaves wrote: One real word of caution. Make darn sure that you have specified the correct target when using dd to copy files as it is very easy to kill all of the data on the computer hard drive that you are using to do the copies. There is no OOPS command and no warnings about overwriting data. Once the command string is entered and you press enter dd starts the transfer. Excellent advice, and this is something that Windows people might not think of. Central to the UNIX paradigm is the operating system making the assumption that the user actually knows what he/she is doing, and actually means what he/she types, and dutifully and immediately does what the user tells it to do. No "Are you sure?" "Are you REALLY REALLY SURE??" hand-holding. Another thing is silence in the case of success. Assume that the computer did what you told it to do...there is no need for it to say "Hey, you told me to do something, so I did it!" That's dumb. The computer should only say something in an unexpected situation, i.e. when there was an error. If you type a command at a UNIX shell and it responds with another shell prompt, it did what it told you to do. And no dancing paperclips. Computing for grownups, when they need to get work done. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: UNIX files and dd, Re: [HP-Agilent-Keysight-equipment] Agilent 54831M
I agree with Dave. The dd program is the bees knees when it comes to byte by byte copies, to and from any source.?
I have used the Windows version of dd to copy files to and from SRAM for installing firmware on older LeCroy scopes. It also comes in handy for making SDCard or PCCard images for industrial machines and the like.
You can get dd for Windows from here: (works just like the Linux version for those that do not have a Linux box.)
The link below is for instructions I wrote years ago for copying binary firmware files to a SRAM care for the LeCroy scopes but it should give you an idea how to use dd. Note that in the case below you do have to have a machine that can install the drivers for SRAM writing under Windows. I think the last version of Windows that can do this is XP but correct me if I am wrong.?
I used to use a program called Memory Card Explorer for doing this but once I discovered dd for free, I now use that. Besides I think MCE won't run on anything newer than XP either. It could be that you could run dd inside a VM under Windows but I don't know if/how that would work. For MCE or dd for SRAM or ATA compliant PCMCIA you need a standard PCMCIA slot not an ExpressCard slot so you have to find an older laptop. I use the Dell D620 or D630 and there are some (but not all) E6400 series that retained that slot.
One real word of caution. Make darn sure that you have specified the correct target when using dd to copy files as it is very easy to kill all of the data on the computer hard drive that you are using to do the copies. There is no OOPS command and no warnings about overwriting data. Once the command string is entered and you press enter dd starts the transfer.
Best to try it out on a test machine that you have a full backup for, or one that you do not care about if you crash it.
73, W3OHM
Sam Reaves
ARS W3OHM
Owner and Moderator of: LeCroy Owners Group on Groups.io (Current and Future Group)
Electronics and Mechanical Hardware Design Engineering Manager
Andritz Rolls Global Research Center (RETIRED)
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UNIX files and dd, Re: [HP-Agilent-Keysight-equipment] Agilent 54831M
On 10/12/20 11:12 PM, Bostonman wrote: I apologize ahead of time, but I lack experience with Linux, so these commands are confusing me.
The file was downloaded as a .zip, but it contains a file with the extension of .dd. Any 'dd' commands I find seem geared towards using a .iso file to make a bootable drive.
Currently I'm using a Raspberry Pi with a SSD drive connected through a USB adapter.
I looked at the link above, but it doesn't make sense to me. One article stated I need to set the block size, and others have extensively long command lines.
So? I remain baffled at how to handle this. First, it's important not to overcomplicate things. From your statements I assume you're coming from the Windows world. In the Windows world, it's common to have one or more programs designed to accomplish a specific task and those programs store data in closed, proprietary formats, creating files that will only work with that specific program. If you've got a dozen programs that all accomplish the same task, they'll each use their own format. The UNIX world is much, much simpler than that. Sure, locked-in file formats do exist, but they are not the norm with common UNIX utilities. The "dd" program does not have a file format. It copies bytes from one place to another. If you tell it to move bytes from a hard disk drive (not a FILE on a hard disk drive, but from the drive itself), and put them into a file on another hard disk drive, the resultant file will contain a byte-for-byte copy of whatever was on the source hard disk. This is commonly referred to as a "disk image". The .ISO file format is poorly-named and largely misunderstood. There is no such thing as "an ISO file". ISO refers to the ISO-9660 file format, which is an on-disk filesystem layout intended for use with optical media. There are many such filesystems, but ISO-9660 is very common on optical media. When you make a disk image file (see paragraph above) of a CD-ROM drive, that would be considered to "be an ISO"...whether that CD-ROM originally contained an ISO-9660 filesystem or not. This is typical American terminological laziness at work, and it leads to confusion. Next, file naming...Another important thing to understand about the UNIX world is that file extensions have no meaning to the system, only to humans. Windows makes a lot of assumptions about the contents of a file based on its extension, but in a UNIX-based OS, there's nothing special about the "." character, and there's nothing special about what may or may not come after it in a filename. Someone having called your file "<filename>.dd" means nothing to the system, and is not used by the system in any way, but it gives me (and soon, you) a clue as to how the file was created if the guy you got it from didn't tell you. It would be useful for you to learn what the "dd" program does and what it's all about. If you understood it, you would see the "instructions" you found online and immediately see how they would apply to your situation, although they were (poorly) written to focus on "ISOs" of CD-ROM disks. The "dd" program copies bytes between sources and destinations. Sources and destinations can be hard disk drives, CD-ROM drives, floppies, USB thumb drives, files on a disk...anything. The "dd" program has a lot of options to manipulate data in different ways. Sometimes the block size is important, but a lot of the time it isn't. Most of the time (but not all) it just tells dd to "read or write the data in chunks this big". For some types of devices it's important, for most it isn't, and for files on a drive it means nothing at all...EXCEPT things generally go a whole lot slower if you use a block size of 1 byte, which is the default unless you tell dd otherwise. I realize learning this is actual work, but this is a give a man a fish/teach a man to fish situation. If you do any amount of "real" computing, you will use this information over and over again. The whole world works this way. The important thing to keep in mind is that UNIX is nothing at all like Windows...do not make any assumptions based on your Windows experience. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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HP HIL keyboard and mouse wanted - in Australia
Hi,
I have just bought HP 1660A Logic Analyser.
I know I can enter text on the front panel but I would like the keyboard and mouse.
I was buying other gear when I was offered the analyser for a very good price - and no shipping!? I scanned over the keyboard port very quickly when I was checking the machine.? Only when I got home did I realize the HIL part.
I have found a couple of keyboards on ebay for very hopeful prices plus huge shipping to Australia.? There seems to be little consistency in shipping charges, I imported a rack mount receiver last month for less than what these sellers will ship a keyboard.? An untested keyboard.
If anyone has a keyboard and/or mouse available in Australia please contact? me.
Or a suggest a source.
Cheers
Mark
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I apologize ahead of time, but I lack experience with Linux, so these commands are confusing me.
The file was downloaded as a .zip, but it contains a file with the extension of .dd. Any 'dd' commands I find seem geared towards using a .iso file to make a bootable drive.
Currently I'm using a Raspberry Pi with a SSD drive connected through a USB adapter.
I looked at the link above, but it doesn't make sense to me. One article stated I need to set the block size, and others have extensively long command lines.
So? I remain baffled at how to handle this.
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Re: Clearing out some stuff. Series 200/300 monitors,umatic vid tape decks, printers
On 10/12/20 9:19 PM, David B via groups.io wrote: I have a boat load of stuff to clear out and thought I would see if anyone wants it before going to the local technology re-purposer.
Sony RGB Trinitron monitors used widely on HP series 200/300 computers.
HP Laserjet II and III printers
Sony umatic professional cassette VCR's with tapes.
A couple HP UNIX workstation computers.
A full size wheeled rack cabinet with custom HP 200 series computer, drawers and disc drive.
Big Bertha plotter? 7580B and lots of old still sealed pens
Bunches of smaller stuff, series 200/330 boxes and cards plus instruments, but most motivated to clear out the big stuff first.
Let me know if interested before it's gone.
Located in Oregon, Not really interested in shipping any big stuff unless you want it so bad you are willing to pay my time and cost to prepare and ship it. Also, I should've mentioned this earlier...please give the folks on the VintHPcom mailing list (also on groups.io). There are a great many people there who will be interested in that hardware and will want to save it from an untimely demise. Please don't recycle this stuff unless you have absolutely no other choice; these systems don't grow on trees and many people strongly want them for either personal or business reasons. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: HP-3456A - Question Regarding Resistance Measurement
On very high resistance ranges as discussed the oils from your hands will affect the resistor. Also there is the possibility of the test terminals being dirty. At least most of the gear I am able to obtain a good cleaning usually pays off. Watch out with IPA it could eat the paint. test it some place safe first. Regards Paul
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Re: Clearing out some stuff. Series 200/300 monitors,umatic vid tape decks, printers
On 10/12/20 9:19 PM, David B via groups.io wrote: I have a boat load of stuff to clear out and thought I would see if anyone wants it before going to the local technology re-purposer.
Sony RGB Trinitron monitors used widely on HP series 200/300 computers.
HP Laserjet II and III printers
Sony umatic professional cassette VCR's with tapes.
A couple HP UNIX workstation computers.
A full size wheeled rack cabinet with custom HP 200 series computer, drawers and disc drive.
Big Bertha plotter? 7580B and lots of old still sealed pens
Bunches of smaller stuff, series 200/330 boxes and cards plus instruments, but most motivated to clear out the big stuff first.
Let me know if interested before it's gone.
Located in Oregon, Not really interested in shipping any big stuff unless you want it so bad you are willing to pay my time and cost to prepare and ship it. Unfortunately you're too far away for me to be able to get much of it, but do you have any SRM Coax interfaces (50962A, etc) for 200/300 series systems? -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: 4262A LCR Meter: 'Fail 2'
I finally found my notes - the 4262A that I repaired also had a "FAIL 2" fault, and the culprit was the "A" half of A11U3, a NJM4558.
Dave Casey
On Fri, Oct 9, 2020 at 1:44 AM Ed Giaimo < edgiaimo@...> wrote: Looking at the 4262A schematic, the circuit topology for the A12 pcba is very similar to the A4 pcba in the 4261A but with slightly different components. That U2 IC is susceptible to damage because of its connection to the test terminals. I have replaced that U2 component on multiple 4261A's that exhibited temperature drift when I blew on that pcba during calibration. Although I have not experienced your particular error code, that op-amp component is a good candidate for replacement anyway.
--Ed
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Clearing out some stuff. Series 200/300 monitors,umatic vid tape decks, printers
I have a boat load of stuff to clear out and thought I would see if anyone wants it before going to the local technology re-purposer.
Sony RGB Trinitron monitors used widely on HP series 200/300 computers.
HP Laserjet II and III printers
Sony umatic professional cassette VCR's with tapes.
A couple HP UNIX workstation computers.
A full size wheeled rack cabinet with custom HP 200 series computer, drawers and disc drive.
Big Bertha plotter? 7580B and lots of old still sealed pens
Bunches of smaller stuff, series 200/330 boxes and cards plus instruments, but most motivated to clear out the big stuff first.
Let me know if interested before it's gone.
Located in Oregon, Not really interested in shipping any big stuff unless you want it so bad you are willing to pay my time and cost to prepare and ship it.
Regards,
David B
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On Mon, Oct 12, 2020 at 8:17 PM Dave McGuire < mcguire@...> wrote: On 10/12/20 7:19 PM, Bostonman wrote:
> I'll have to post some pictures again. I don't remember what I posted
> before, what you read, and what I've already explained.
>
> Basically this scope doesn't have any power cables. It has a CD-ROM, a
> 3.5" drive, and a 44-pin hard drive. The only power cables are two
> separate tiny connectors with 5V and ground.
>
> Some good news, I managed to get in touch with the person who owned this
> before me (I had to dig through old Craig's List emails and try to
> locate his number). He posted a copy of the original hard drive contents
> (he no longer has the hard drive), but all I have is a .zip file he
> created in Linux; and it contains a .dd file.
>
> I'm uncertain how to handle this. I have a laptop with Ubuntu and a
> Raspberry Pi, but believe I need to take a blank drive and make it a
> boot drive (I have a Windows program that will do that), but I'm
> uncertain how to handle the .dd file.
On any sane linux system, you should be able to mount the dd image, assuming it's a raw disk image. This will allow you to at least see what's on the drive image,?look at the partition table and such.
I seem to need to do this every 5 years or so, and I always need to Google for the details, but this e.g. looks likely .
?
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On 10/12/20 7:19 PM, Bostonman wrote: I'll have to post some pictures again. I don't remember what I posted before, what you read, and what I've already explained.
Basically this scope doesn't have any power cables. It has a CD-ROM, a 3.5" drive, and a 44-pin hard drive. The only power cables are two separate tiny connectors with 5V and ground.
Some good news, I managed to get in touch with the person who owned this before me (I had to dig through old Craig's List emails and try to locate his number). He posted a copy of the original hard drive contents (he no longer has the hard drive), but all I have is a .zip file he created in Linux; and it contains a .dd file.
I'm uncertain how to handle this. I have a laptop with Ubuntu and a Raspberry Pi, but believe I need to take a blank drive and make it a boot drive (I have a Windows program that will do that), but I'm uncertain how to handle the .dd file.
My guess: I create a bootable drive, unzip the .dd. file, and copy/paste all the directories/files onto the bootable drive under the main directory. No. The file extension of .dd suggests that he created the file using the program "dd". Though some people do this, there is no standard file naming convention for files manipulated with the "dd" program, which simply moves data around between devices and files. It doesn't know about filesystems or data formats or anything else, just raw data to/from devices. You will need to use dd on your Linux (or other UNIX) system to write that data back to a drive. One potential issue here is that things may go awry if the destination drive is larger than the original drive was; depending on how Windows handles devices and filesystems. It may deal with it, and it may not. (I'm not a Windows guy) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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I'll have to post some pictures again. I don't remember what I posted before, what you read, and what I've already explained.
Basically this scope doesn't have any power cables. It has a CD-ROM, a 3.5" drive, and a 44-pin hard drive. The only power cables are two separate tiny connectors with 5V and ground.
Some good news, I managed to get in touch with the person who owned this before me (I had to dig through old Craig's List emails and try to locate his number). He posted a copy of the original hard drive contents (he no longer has the hard drive), but all I have is a .zip file he created in Linux; and it contains a .dd file.
I'm uncertain how to handle this. I have a laptop with Ubuntu and a Raspberry Pi, but believe I need to take a blank drive and make it a boot drive (I have a Windows program that will do that), but I'm uncertain how to handle the .dd file.
My guess: I create a bootable drive, unzip the .dd. file, and copy/paste all the directories/files onto the bootable drive under the main directory.
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Many fans can be given extra life by adding a few drops of light oil on the bearing. ?
Unless the fan winding is burnt out, this method of restoration works well. ?Just carefully peel off the round plastic on top of the fan, add 2 or 3 drops of oil to the bearing ?and reseal. ?I use Nano-oil as I also repair clocks. ?Nano-oil last a long time because of the nano diamond ball bearings are in the oil carrier.
--
Regards, Bernie Murphy
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Re: HP-3456A - Question Regarding Resistance Measurement
Resistors utilized in metering or other circuits that require good precision is why manufacturers either select their components or rely upon custom made products to their specifications instead of normally available off-the-shelf components.? Custom made parts are why we see such odd values in equipment.? If you are lucky you will find resistors that actually fit normal industry resistance values but are not simply bought in bulk assuming that they will work.? Either that or final test of the product may require change-out of the offending part to obtain the specified operational tolerance of the item.
?
Greg
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Re: HP435 measuring head? kW's?
parkertest is an ebay username.? Search for HP 8481A on ebay and you'll find listings for both repairing 8481As and for refurb units.
Orin.
On Mon, Oct 12, 2020 at 01:15 PM, Orin Eman wrote:
'parkertest'
What is (where is) a "parkertest?"
Is there a link to the actual page where (parkertest + Parker Test + Bruce Parker + Parker Test Equipment) quotes < 500 USD, to repair an H.P. power sensor?
It's been mentioned more than once, that people are repairing power sensors... and I'd like to find out what they are doing.
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Martin
Dave McGuire
Sam Reaves