Re: Placing Shelf on Casters for HP Equipment
Yes, it was 'Point Of Sale' hardware. I bought both minicomputers, ten in counter LASER scanners along with 14 cash registers and 14 printers. Two complete systems, from two stores..They threw in two chargers and an electric pallet jack, all for $100. I scraped the scanners for the LASER tubes and power supplies. I sold them for $400, and I got about $75 for the machined aluminum housings. The profits went to more equipment for the shop, at the Orlando Hamfest.
I take it POS stands for Point Of Sale, not Piece Of S***.? When I was in engineering school in the 1980s, we used the DEC Pro 350 computers, and they actually had an operating system called pOS!? Not a well thought out name!? ? ? ?Jim Ford?
Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message -------- Date: 11/8/21 12:33 AM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] Placing Shelf on Casters for HP Equipment
There are also 23" wide racks that came from the Telco industry.
I have two, dual sized enclosed racks They are 19", but you can remove the doors and side panels, then turn it 90 degrees to use it as a 23" rack.
They are from some long gone National Semiconductor Datachecker POS systems that were scrapped 25 years ago. On Sun, Nov 7, 2021 at 10:31 PM Dave McGuire < mcguire@...> wrote: On 11/7/21 8:38 PM, Matt Huszagh wrote:
> I googled "HP test equipment rack" and the 19" rack popped up. I have
> seen these before, though I didn't know the term (or know that it was a
> standard). I also did not know that these are what HP, Agilent and
> Keysight use for their test equipment racks.
? ?Well, they followed the 19" rack standard.? Just like all of the
computer manufacturers (HP included) followed it too.
? ?The vernacular: One "rack U" (rack unit) is 1.75".? A "1U"
rack-mounted device is 1.75" tall, a "2U" chassis is 3.5", etc.? About
95% of the hardware you'll run across, test equipment and server-class
computers alike, is sized in these increments.? Soon you'll be able to
recognize them on sight and plan out your rack space allocations: "Oh, I
see that HP 3325A is a 3U box".? "Ah, I can put a 1U file server right
here".
? ?Look for a picture of the front one of these racks, empty, and look
at the holes facing you on the left and right.? Notice the spacing
pattern of the holes.? It looks irregular, but if you stare at it for a
moment you'll see that they're spaced out for 1.75" increments.
? ?All of this works amazingly well, and you will love it.
? ?This isn't just test equipment stuff.? If you haven't ever seen a
datacenter in person, surely you've seen pictures of them.? Those are
the same racks.
? ?Keyboardless synthesizers, signal processors, and amplifiers in
recording studios and on on concert stages...same racks.
? ?AT&T came up with this standard for telephony equipment in
1922...Yes, 99 years ago.
> I'm not sure if this is a good excuse but I'm relatively young (< 30)
> and only been doing electronics for the last couple years, when I
> started teaching myself. I also don't come from an engineering
> background, so I've probably missed some things that are evident to
> others in the field. I did study physics undergrad though, and research
> is one of the places I've come across these. But, none of us were too
> concerned that these were called 19" racks.
? ?It's not a good excuse. ;)? But it's never too late to catch up, and
you can fill in all of the knowledge blanks here.
? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Placing Shelf on Casters for HP Equipment
A number of people have mentioned stability without proper loading and
braces being a concern for these 4 post racks. It seems like using
several shelves that are each fastened to all 4 posts and then placing
some gear on there would provide this support to the shelf. Is that
right?
Matt
|
Re: Question: XY (XYZ or Vector) instrument CRT, replacement with an LCD ?
Hello, for me is one simple solution on the HP182T with dead CRT, I got ready X,Y output there is someone have put one 8 inch LCD display mods on X Y input?
Thank you.
Francesco
?
?
Sent:?Monday, November 08, 2021 at 4:48 PM
From:?"green" <hrgerson@...>
To:[email protected]
Subject:?Re: [HP-Agilent-Keysight-equipment] Question: XY (XYZ or Vector) instrument CRT, replacement with an LCD ?
hi,
Just to pull the conversation back to the?? *electronics*? of the replacement of a XYZ CRT with an LCD ??
???? { rather than the programming or software, for now }.
Does anyone have any technical expertise with? "picking off" ? the vector type (non-raster) CRT XYZ signals? (presumably from the low voltage deflection amplifiers)? ?
Assuming that somewhere in the deflection amplifier signal chain, there might be some low voltage +/- 5V signals that could be used
? --- so that could then be fed into an LCD module ( such as the $55? STM32F746G-DISCO module ?).
For this project question, the CRT display is a simple XYZ vector display, not a raster CRT:
The NewScope modules are too expensive to consider,
and this CRT issue is not concerned with longevity nor with hypothetical future replacements of the LCD with another LCD, etc.
Nor with the use of yet another CRT.
The point being that the STM LCD module may represent the possibility of actually capturing the data from, say a Tek 576 Curve Tracer( as an example), that would allow such data to be imported into a laptop for data manipulation, comparison? and file storage that could be useful for component R&D & project development, beyond the current instrument limitations.
The CRT's of these type of instruments are dying and are not easily replaceable.
Why not move forward with an inexpensive LCD module for these instruments ?
>>>? In any event, if anyone has direct technical experience with the type of XYZ CRT deflection signal pick-off and manipulation posed by this question, their experience or thoughts would be appreciated !
(i.e. , specifically for the Tek 576 CT,? would those signals have to be buffered or level shifted, etc. ?)
-- If anyone has come across a Website or a Blog conveying? *inexpensive*? vector XYZ CRT replacement ( or signal capture ) with an LCD,
I'd appreciate knowing about it !!
Not sure if there are other descriptions or jargon ( i.e.? " Scan Converter " etc. ) that might have been used to describe this sort of problem, perhaps published in "The Review of Scientific Instruments", or IEEE Transactions ?
There must have been sectors of the industry that encountered and solved this issue *inexpensively* ?
?
thank you,
rick?
Note:
-- A number of Web references for vector XYZ type concepts have been discussed, including a well explained reference to a Patent, in the Tek Groups .io discussion:?
/g/TekScopes/topic/86718765
-- Not worried about the Tek 576 switch settings / plastic fiber display issues for now;? - those are simply a decode issue which can be easily solved and added to the converted LCD display, later on !?
|
second photo shows that BNCs can be fit into the holes for the fixed leads....
Might be a nice practical improvement.
|
Are they actually coaxial on the 412?? Wow, I didn't realize that. I stand corrected.
So, ok, the OP will need to get some coaxial cable rather than single-conductor silicone probe wire.
-Dave
toggle quoted message
Show quoted text
On 11/8/21 11:53 AM, Bob Albert via groups.io wrote: It's not that simple.? The leads are coaxial cables with terminations such that four wire resistance can be done.? The manual shows it but you will need some special cable.
Bob
On Monday, November 8, 2021, 08:28:31 AM PST, Dave McGuire <mcguire@...> wrote:
On 11/8/21 11:24 AM, JIM Rogers via groups.io wrote:
> I picked up a HP 412 AR and the leads were cut off. Where can I find
> replacements, or build them.
? The 412AR dates back to well over half a century ago; you will not
likely find "HP 412AR leads".? Your best bet is to get some nice
silicone-insulated wire and quality alligator clips and build a set of
leads.
? Decent silicone wire, amazingly from China, can be had via Amazon.
Look at the "BNTECHGO" brand; I've been very pleased with them. (and I'm
a quality snob)
? ? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
--
Dave McGuire, AK4HZ
New Kensington, PA
|
It's not that simple.? The leads are coaxial cables with terminations such that four wire resistance can be done.? The manual shows it but you will need some special cable.
Bob
On Monday, November 8, 2021, 08:28:31 AM PST, Dave McGuire <mcguire@...> wrote:
On 11/8/21 11:24 AM, JIM Rogers via groups.io wrote:
> I picked up a HP 412 AR and the leads were cut off. Where can I find
> replacements, or build them.
? The 412AR dates back to well over half a century ago; you will not
likely find "HP 412AR leads".? Your best bet is to get some nice
silicone-insulated wire and quality alligator clips and build a set of
leads.
? Decent silicone wire, amazingly from China, can be had via Amazon.
Look at the "BNTECHGO" brand; I've been very pleased with them. (and I'm
a quality snob)
? ? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Placing Shelf on Casters for HP Equipment
I take it POS stands for Point Of Sale, not Piece Of S***.? When I was in engineering school in the 1980s, we used the DEC Pro 350 computers, and they actually had an operating system called pOS!? Not a well thought out name!? ? ? ?Jim Ford?
Sent from my Verizon, Samsung Galaxy smartphone
toggle quoted message
Show quoted text
-------- Original message -------- From: "Michael A. Terrell" <terrell.michael.a@...> Date: 11/8/21 12:33 AM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] Placing Shelf on Casters for HP Equipment
There are also 23" wide racks that came from the Telco industry.
I have two, dual sized enclosed racks They are 19", but you can remove the doors and side panels, then turn it 90 degrees to use it as a 23" rack.
They are from some long gone National Semiconductor Datachecker POS systems that were scrapped 25 years ago. On Sun, Nov 7, 2021 at 10:31 PM Dave McGuire < mcguire@...> wrote: On 11/7/21 8:38 PM, Matt Huszagh wrote:
> I googled "HP test equipment rack" and the 19" rack popped up. I have
> seen these before, though I didn't know the term (or know that it was a
> standard). I also did not know that these are what HP, Agilent and
> Keysight use for their test equipment racks.
? ?Well, they followed the 19" rack standard.? Just like all of the
computer manufacturers (HP included) followed it too.
? ?The vernacular: One "rack U" (rack unit) is 1.75".? A "1U"
rack-mounted device is 1.75" tall, a "2U" chassis is 3.5", etc.? About
95% of the hardware you'll run across, test equipment and server-class
computers alike, is sized in these increments.? Soon you'll be able to
recognize them on sight and plan out your rack space allocations: "Oh, I
see that HP 3325A is a 3U box".? "Ah, I can put a 1U file server right
here".
? ?Look for a picture of the front one of these racks, empty, and look
at the holes facing you on the left and right.? Notice the spacing
pattern of the holes.? It looks irregular, but if you stare at it for a
moment you'll see that they're spaced out for 1.75" increments.
? ?All of this works amazingly well, and you will love it.
? ?This isn't just test equipment stuff.? If you haven't ever seen a
datacenter in person, surely you've seen pictures of them.? Those are
the same racks.
? ?Keyboardless synthesizers, signal processors, and amplifiers in
recording studios and on on concert stages...same racks.
? ?AT&T came up with this standard for telephony equipment in
1922...Yes, 99 years ago.
> I'm not sure if this is a good excuse but I'm relatively young (< 30)
> and only been doing electronics for the last couple years, when I
> started teaching myself. I also don't come from an engineering
> background, so I've probably missed some things that are evident to
> others in the field. I did study physics undergrad though, and research
> is one of the places I've come across these. But, none of us were too
> concerned that these were called 19" racks.
? ?It's not a good excuse. ;)? But it's never too late to catch up, and
you can fill in all of the knowledge blanks here.
? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Question: XY (XYZ or Vector) instrument CRT, replacement with an LCD ?
hi, Just to pull the conversation back to the?? *electronics*? of the replacement of a XYZ CRT with an LCD ?? ???? { rather than the programming or software, for now }. Does anyone have any technical expertise with? "picking off" ? the vector type (non-raster) CRT XYZ signals? (presumably from the low voltage deflection amplifiers)? ? Assuming that somewhere in the deflection amplifier signal chain, there might be some low voltage +/- 5V signals that could be used ? --- so that could then be fed into an LCD module ( such as the $55? STM32F746G-DISCO module ?). For this project question, the CRT display is a simple XYZ vector display, not a raster CRT: The NewScope modules are too expensive to consider, and this CRT issue is not concerned with longevity nor with hypothetical future replacements of the LCD with another LCD, etc. Nor with the use of yet another CRT. The point being that the STM LCD module may represent the possibility of actually capturing the data from, say a Tek 576 Curve Tracer( as an example), that would allow such data to be imported into a laptop for data manipulation, comparison? and file storage that could be useful for component R&D & project development, beyond the current instrument limitations. The CRT's of these type of instruments are dying and are not easily replaceable. Why not move forward with an inexpensive LCD module for these instruments ? >>>? In any event, if anyone has direct technical experience with the type of XYZ CRT deflection signal pick-off and manipulation posed by this question, their experience or thoughts would be appreciated ! (i.e. , specifically for the Tek 576 CT,? would those signals have to be buffered or level shifted, etc. ?) -- If anyone has come across a Website or a Blog conveying? *inexpensive*? vector XYZ CRT replacement ( or signal capture ) with an LCD, I'd appreciate knowing about it !! Not sure if there are other descriptions or jargon ( i.e.? " Scan Converter " etc. ) that might have been used to describe this sort of problem, perhaps published in "The Review of Scientific Instruments", or IEEE Transactions ? There must have been sectors of the industry that encountered and solved this issue *inexpensively* ? ? thank you, rick? Note: -- A number of Web references for vector XYZ type concepts have been discussed, including a well explained reference to a Patent, in the Tek Groups .io discussion:? /g/TekScopes/topic/86718765-- Not worried about the Tek 576 switch settings / plastic fiber display issues for now;? - those are simply a decode issue which can be easily solved and added to the converted LCD display, later on !?
|
On 11/8/21 11:24 AM, JIM Rogers via groups.io wrote: I picked up a HP 412 AR and the leads were cut off. Where can I find replacements, or build them. The 412AR dates back to well over half a century ago; you will not likely find "HP 412AR leads". Your best bet is to get some nice silicone-insulated wire and quality alligator clips and build a set of leads. Decent silicone wire, amazingly from China, can be had via Amazon. Look at the "BNTECHGO" brand; I've been very pleased with them. (and I'm a quality snob) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
I picked up a HP 412 AR and the leads were cut off. Where can I find replacements, or build them.
|
Re: Question: XY (XYZ or Vector) instrument CRT, replacement with an LCD ?
On Sunday 07 November 2021 11:40:33 am peter bunge wrote: It really soured me against Microsoft. A lot of things have done that for me over the years. I have run nothing but linux since 1999, won't have anything to do with that company if it's at all possible... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
|
Re: Placing Shelf on Casters for HP Equipment
Hi Dave Just an acknowledgment and a bit more info for the new be
I was trying to be general and keep it simple as the person was only just introduced to 19 in racks
Agreed light units can be supported from the front panel only
Possibly an item up to I ft deep might be OK depending on how heavy
So a patch panel does not require supporting only the cables but I would consider a HP 8620 to heavy
Regarding the type of racks yes there are ones with threaded holes and they tend to have BA threads
Regarding Caged nutt they come in a variety of metric thread sizes and also BA
The cages are also designed for different metal thickness so it is important to know the problems when using the wrong size
Regarding Getting racks there are some very nice racks from server rooms that are replaced with smaller units unfortunately a lot are 6 ft or taller
But some of these are in kit form and can easily be shortened. Side covers can either be modified or simply not used
Regards Paul
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Dave McGuire Sent: 08 November 2021 15:00 To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] Placing Shelf on Casters for HP Equipment On 11/8/21 6:45 AM, Paul Bicknell wrote: Equipment can have rack wings this allows the equipment to be bolted to the front of the 19 rack to prevent it moving ( NOT to Support it or hold it up )
*The equipment must be supported from front to back on shelves or side runners* Supporting from those wings (commonly called "ears") is referred to as "cantilevered mounting". This is actually very common, acceptable, and the designers' intentions for many things. You'd not mount, say, an HP 8566 that way, but many HP instruments are just fine with cantilevered mounting. Use judgement. These will have square holes down both sides and this is where the cage nuts go as mentioned in an earlier mail Note that not all holes are square; I found it to be about 50/50. There are square holes, round holes, and threaded round holes, all of which are common. Dave McGuire, AK4HZ New Kensington, PA
|
Your body is a capacitor, charged to varying voltage as you move around.? Any sensitive meter will jump around as you approach or withdraw.
?
Dave Wise
?
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From: [email protected] [mailto:[email protected]]
On Behalf Of Askild via groups.io
Sent: Sunday, November 07, 2021 10:34 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 401 c VTVM
?
Hi Mark,
Its normal for voltmeters with very high input impedance to not show stable 0V when probe is hanging free. Mine also jump around when touching the probe.?
The input impedance of the 410C is about 100MOhm, compared to most multimeters today that have 10MOhm.
To see if the voltmeter is showing 0V with no voltage applied, you need to short the voltmeter probe and the ground wire.
?
Hello one and all,
I have recently acquired a HP 410 C meter from a friend.
It works great measuring resistance. I do not have the AC probe that may have come with it, so I cannot attest to its AC measuring accuracy. However when I try to measure something as simple as a AAA or 9-volt battery the meter does something I am unable to
explain.
The meter movement will not land or stay on zero when I turn the function switch to DC+ or DC-. I find that when I handle the DC probe it is when the meter goes crazy. (also technical term used in describing human behavior).
If I run my hand along the probe wire I get the same reaction.?
If I conduct the test with out letting the meter settle at zero I get a very accurate reading.
I have checked the internals of the probe and find that the center core of the coax is connected to the resistor which is connected to the tip.
The shield is cut back and covered with shrink tubing eliminating any possible "short"
I have checked the continuity of both the shield and the inner wire of the coax and there is nothing unusual to report.
Any suggestions would be greatly appreciated
Respectfully
Mark
|
On November 8, 2021 10:27:59 AM "Chris Wilkson via groups.io" <cwilkson@...> wrote: Real quick note.
I've gotten many inquiries on the Model M keyboards.
They are keepers...I use both of them every day. Yeah I think many people inexplicably interpreted your initial post as "I want to get rid of all of this stuff". It was actually pretty clear that this was not your intention. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Real quick note.
I've gotten many inquiries on the Model M keyboards.
They are keepers...I use both of them every day.
|
Re: Placing Shelf on Casters for HP Equipment
On 11/8/21 6:45 AM, Paul Bicknell wrote: Equipment can have rack wings this allows the equipment to be bolted to the front of the 19 rack to prevent it moving ( NOT to Support it or hold it up )
*The equipment must be supported from front to back on shelves? or side runners* Supporting from those wings (commonly called "ears") is referred to as "cantilevered mounting". This is actually very common, acceptable, and the designers' intentions for many things. You'd not mount, say, an HP 8566 that way, but many HP instruments are just fine with cantilevered mounting. Use judgement. These will have square holes down both sides and this is where the cage nuts go as mentioned in an earlier mail Note that not all holes are square; I found it to be about 50/50. There are square holes, round holes, and threaded round holes, all of which are common. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: Placing Shelf on Casters for HP Equipment
Yes, I forgot to mention in my earlier post that I acquired all three of my racks for free. With some patience and a lot of trolling, one can usually find a suitable rack. I know that they are around here in Central Florida, and I was able to find them along Colorado¡¯s front range as well.
DaveD
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On Nov 8, 2021, at 09:20, Paul Amaranth <paul@...> wrote:
?I like the four post racks, the two post relay racks never
seemed a good choice for test equipment.
With some scrounging, they can be very cheap. I got one free
off of craigslist and the last one I got was something like
$10 at an auction. I also have a couple of half size rack
cabinets that had equipment built into them that are pretty
handy.
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
|
Re: Placing Shelf on Casters for HP Equipment
I like the four post racks, the two post relay racks never
seemed a good choice for test equipment.
With some scrounging, they can be very cheap. I got one free
off of craigslist and the last one I got was something like
$10 at an auction. I also have a couple of half size rack
cabinets that had equipment built into them that are pretty
handy.
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
|
Re: Placing Shelf on Casters for HP Equipment
I've used the Starcase racks and had good luck with them.? The ability to access through (and mount things to) all four sides is nice.
But as Dave said, the base configuration is very wobbly.? Starcase has various corner, diagonal, and side braces that are almost mandatory to stiffen the frame.? But with those installed, I really, really like these racks.
John
On Nov 8, 2021, at 7:28 AM, Dave Daniel < kc0wjn@...> wrote:
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Show quoted text
A lot of excellent points have been made in this thread so far. Here are some additional considerations:
The ¡°Metro¡± wire shelving works reasonably well. Using casters works if one doesn¡¯t overload the shelves. Even if one overloadsthe shelves a bit they will work unless one tries to roll the loaded shelving. A perticularly nasty failure mode for these is for the caster and the cylinder into which it is screwed to break out of the leg tubing sideways (ask me how I know).
Uline also sells metal wire shelving. While a bit more expensive, those shelf units are better built.
Based on ths OP¡¯s question about the StarTech rack, I have found StarTech¡¯s products to not be very reliable. Furthermore, that open frame has very little rigidity. Installing light-weight items in it will stiffen it, particularly if the items are fastened to the rack at both the front and rear of the rack. Installing heavy items will *require* being fastened at front and back. Racks with side covers fastened to the rack frame will be much stronger.
I keep my heavy instruments (HP 8566B and HP 8660D) on the bench and lighter items (HP 339A and others) in my rack on rack shelves and move them off the shelves and onto the bench when I want to use them. I have yet to find a convenient arrangement of rack, bench and the position of instruments in the rack that affords useful access to all instruments in the rack. The closest I ever came to that was to have a short rack sitting on the bench. But eventually I just stacked the instruments on top of one another without the rack. My rack now sits in the lab away from the. ench and is used onlg to store instruments.
I have had three heavy-duty racks over the last forty or so years, all of which were intended for heavy items. The first was a rack intended to hold Dictphone logging recorders and was built like a tank. The second and third were originally used to hold servers. The one I currently have (probably sinething like 32U tall) is very strong, but I wouldn¡¯t attemp to roll it without unloading a few pieces from it first.
Be very careful about weight distribution (top to bottom) when loading a rack or shelving, particularly if one intends to try and roll it around. Heavy items down low, lighter items towards the top.
DaveD
On Nov 8, 2021, at 06:45, Paul Bicknell <admin@...> wrote:
?
Hi all
?
Just a few observations and hopefully a bit of help
?
Regarding? 19 inch racks? don¡¯t be too hard on the new be as like a lot of? people getting into the electronics industry
Have an excellent Brain on them but often lacking in practical skills
That is why I spent over a month at the beginning of the year designing and making a new lab for mature student training
This will hopefully continue with passing on hands on experience with test equipment ( prior to lock down we had over 200 students pass through )
?
Back to racks, ?a typical 19 inch rack made by HP can be seen in the Photos file on this site and in 0 to 99 Equipment Lab Photos
?
/g/HP-Agilent-Keysight-equipment/photo/256676/3227464?p=Created%2C%2C%2C20%2C2%2C0%2C0
?
Now back to the original question from Matt
as do we know if Matt is using modem or older test equipment that is 19 inch compatible and how much does he have
?
Your best configuration might be to split it up as in use a 19 rack for the heavy stuff and a deep bench with a shelf for lighter equipment etc.
?
all can be on wheels , regarding centre of gravity my standard is all the wheels should be mounted so the vertical line always falls 2 inches outside the rack
?
OK Matt a few bits of info on 19 racks?
Equipment can have rack wings this allows the equipment to be bolted to the front of the 19 rack to prevent it moving ( NOT to Support it or hold it up )
The equipment must be supported from front to back on shelves? or side runners
?
This also allows for equipment to be pulled out so you can reconfigure connections on the back
?
So for a 19 rack to be useful to hold and use test equipment it requires 4 vertical supports 2 at the front and 2 at the rear
These will have square holes down both sides and this is where the cage nuts go as mentioned in an earlier mail
?
Now you require the equipment supports from back to front the best racks and easiest to configure?
have additional cage nut holes on side face of all 4 verticals corners of the rack
?
Other arrangements for the support rails are available but less friendly when making up out of second hand components
?
Please feel free to come back as selecting and installing cage nuts is a neck that must be learnt and can be one of the essayist ways to draw blood
?
Regards Paul
?
?
?
?
From: [email protected] [mailto:[email protected]] On Behalf Of Michael A. Terrell
Sent: 08 November 2021 08:34
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Placing Shelf on Casters for HP Equipment
?
There are also 23" wide racks that came from the Telco industry.
I have two, dual sized enclosed racks They are 19", but you can remove the doors and side panels, then turn it 90 degrees to use it as a 23" rack.
They are from some long gone National Semiconductor Datachecker POS systems that were scrapped 25 years ago.
?
On Sun, Nov 7, 2021 at 10:31 PM Dave McGuire <mcguire@...> wrote:
On 11/7/21 8:38 PM, Matt Huszagh wrote:
> I googled "HP test equipment rack" and the 19" rack popped up. I have
> seen these before, though I didn't know the term (or know that it was a
> standard). I also did not know that these are what HP, Agilent and
> Keysight use for their test equipment racks.
? ?Well, they followed the 19" rack standard.? Just like all of the
computer manufacturers (HP included) followed it too.
? ?The vernacular: One "rack U" (rack unit) is 1.75".? A "1U"
rack-mounted device is 1.75" tall, a "2U" chassis is 3.5", etc.? About
95% of the hardware you'll run across, test equipment and server-class
computers alike, is sized in these increments.? Soon you'll be able to
recognize them on sight and plan out your rack space allocations: "Oh, I
see that HP 3325A is a 3U box".? "Ah, I can put a 1U file server right
here".
? ?Look for a picture of the front one of these racks, empty, and look
at the holes facing you on the left and right.? Notice the spacing
pattern of the holes.? It looks irregular, but if you stare at it for a
moment you'll see that they're spaced out for 1.75" increments.
? ?All of this works amazingly well, and you will love it.
? ?This isn't just test equipment stuff.? If you haven't ever seen a
datacenter in person, surely you've seen pictures of them.? Those are
the same racks.
? ?Keyboardless synthesizers, signal processors, and amplifiers in
recording studios and on on concert stages...same racks.
? ?AT&T came up with this standard for telephony equipment in
1922...Yes, 99 years ago.
> I'm not sure if this is a good excuse but I'm relatively young (< 30)
> and only been doing electronics for the last couple years, when I
> started teaching myself. I also don't come from an engineering
> background, so I've probably missed some things that are evident to
> others in the field. I did study physics undergrad though, and research
> is one of the places I've come across these. But, none of us were too
> concerned that these were called 19" racks.
? ?It's not a good excuse. ;)? But it's never too late to catch up, and
you can fill in all of the knowledge blanks here.
? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Placing Shelf on Casters for HP Equipment
A lot of excellent points have been made in this thread so far. Here are some additional considerations:
The ¡°Metro¡± wire shelving works reasonably well. Using casters works if one doesn¡¯t overload the shelves. Even if one overloadsthe shelves a bit they will work unless one tries to roll the loaded shelving. A perticularly nasty failure mode for these is for the caster and the cylinder into which it is screwed to break out of the leg tubing sideways (ask me how I know).
Uline also sells metal wire shelving. While a bit more expensive, those shelf units are better built.
Based on ths OP¡¯s question about the StarTech rack, I have found StarTech¡¯s products to not be very reliable. Furthermore, that open frame has very little rigidity. Installing light-weight items in it will stiffen it, particularly if the items are fastened to the rack at both the front and rear of the rack. Installing heavy items will *require* being fastened at front and back. Racks with side covers fastened to the rack frame will be much stronger.
I keep my heavy instruments (HP 8566B and HP 8660D) on the bench and lighter items (HP 339A and others) in my rack on rack shelves and move them off the shelves and onto the bench when I want to use them. I have yet to find a convenient arrangement of rack, bench and the position of instruments in the rack that affords useful access to all instruments in the rack. The closest I ever came to that was to have a short rack sitting on the bench. But eventually I just stacked the instruments on top of one another without the rack. My rack now sits in the lab away from the. ench and is used onlg to store instruments.
I have had three heavy-duty racks over the last forty or so years, all of which were intended for heavy items. The first was a rack intended to hold Dictphone logging recorders and was built like a tank. The second and third were originally used to hold servers. The one I currently have (probably sinething like 32U tall) is very strong, but I wouldn¡¯t attemp to roll it without unloading a few pieces from it first.
Be very careful about weight distribution (top to bottom) when loading a rack or shelving, particularly if one intends to try and roll it around. Heavy items down low, lighter items towards the top.
DaveD
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On Nov 8, 2021, at 06:45, Paul Bicknell <admin@...> wrote:
? Hi all ? Just a few observations and hopefully a bit of help ? Regarding? 19 inch racks? don¡¯t be too hard on the new be as like a lot of? people getting into the electronics industry Have an excellent Brain on them but often lacking in practical skills That is why I spent over a month at the beginning of the year designing and making a new lab for mature student training This will hopefully continue with passing on hands on experience with test equipment ( prior to lock down we had over 200 students pass through ) ? Back to racks, ?a typical 19 inch rack made by HP can be seen in the Photos file on this site and in 0 to 99 Equipment Lab Photos ? /g/HP-Agilent-Keysight-equipment/photo/256676/3227464?p=Created%2C%2C%2C20%2C2%2C0%2C0 ? Now back to the original question from Matt as do we know if Matt is using modem or older test equipment that is 19 inch compatible and how much does he have ? Your best configuration might be to split it up as in use a 19 rack for the heavy stuff and a deep bench with a shelf for lighter equipment etc. ? all can be on wheels , regarding centre of gravity my standard is all the wheels should be mounted so the vertical line always falls 2 inches outside the rack ? OK Matt a few bits of info on 19 racks? Equipment can have rack wings this allows the equipment to be bolted to the front of the 19 rack to prevent it moving ( NOT to Support it or hold it up ) The equipment must be supported from front to back on shelves? or side runners ? This also allows for equipment to be pulled out so you can reconfigure connections on the back ? So for a 19 rack to be useful to hold and use test equipment it requires 4 vertical supports 2 at the front and 2 at the rear These will have square holes down both sides and this is where the cage nuts go as mentioned in an earlier mail ? Now you require the equipment supports from back to front the best racks and easiest to configure? have additional cage nut holes on side face of all 4 verticals corners of the rack ? Other arrangements for the support rails are available but less friendly when making up out of second hand components ? Please feel free to come back as selecting and installing cage nuts is a neck that must be learnt and can be one of the essayist ways to draw blood ? Regards Paul ? ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Michael A. Terrell
Sent: 08 November 2021 08:34
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Placing Shelf on Casters for HP Equipment ? There are also 23" wide racks that came from the Telco industry. I have two, dual sized enclosed racks They are 19", but you can remove the doors and side panels, then turn it 90 degrees to use it as a 23" rack. They are from some long gone National Semiconductor Datachecker POS systems that were scrapped 25 years ago. ? On Sun, Nov 7, 2021 at 10:31 PM Dave McGuire <mcguire@...> wrote: On 11/7/21 8:38 PM, Matt Huszagh wrote:
> I googled "HP test equipment rack" and the 19" rack popped up. I have
> seen these before, though I didn't know the term (or know that it was a
> standard). I also did not know that these are what HP, Agilent and
> Keysight use for their test equipment racks.
? ?Well, they followed the 19" rack standard.? Just like all of the
computer manufacturers (HP included) followed it too.
? ?The vernacular: One "rack U" (rack unit) is 1.75".? A "1U"
rack-mounted device is 1.75" tall, a "2U" chassis is 3.5", etc.? About
95% of the hardware you'll run across, test equipment and server-class
computers alike, is sized in these increments.? Soon you'll be able to
recognize them on sight and plan out your rack space allocations: "Oh, I
see that HP 3325A is a 3U box".? "Ah, I can put a 1U file server right
here".
? ?Look for a picture of the front one of these racks, empty, and look
at the holes facing you on the left and right.? Notice the spacing
pattern of the holes.? It looks irregular, but if you stare at it for a
moment you'll see that they're spaced out for 1.75" increments.
? ?All of this works amazingly well, and you will love it.
? ?This isn't just test equipment stuff.? If you haven't ever seen a
datacenter in person, surely you've seen pictures of them.? Those are
the same racks.
? ?Keyboardless synthesizers, signal processors, and amplifiers in
recording studios and on on concert stages...same racks.
? ?AT&T came up with this standard for telephony equipment in
1922...Yes, 99 years ago.
> I'm not sure if this is a good excuse but I'm relatively young (< 30)
> and only been doing electronics for the last couple years, when I
> started teaching myself. I also don't come from an engineering
> background, so I've probably missed some things that are evident to
> others in the field. I did study physics undergrad though, and research
> is one of the places I've come across these. But, none of us were too
> concerned that these were called 19" racks.
? ?It's not a good excuse. ;)? But it's never too late to catch up, and
you can fill in all of the knowledge blanks here.
? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Michael A. Terrell
Francesco
Dave McGuire
Paul Bicknell