Re: HP-3586B PS problem - connector J2 overheating
Thanks Peter,?
I am glad to hear that I'm not alone with regard to the connector overheating failure on the 3586s. When I first saw that both had overheated at roughly the same time and in the same place I suspected that it was probably the connector itself, but then thought that nothing could be that simple. Thanks for the repair suggestion. I will follow through with it. ?Reminded me of a batch of 80s ?HP microwave testing equipment I picked up as a lot for the parts. Practically all the knobs had crumbled and fallen off the units. How could the HP engineers know what would happen to certain components after 30 years.?
I had no idea that the pins were spring loaded and would fail under excess heat. Replacement of the connector should not be too much of a problem.?
Many thanks for the answer to my query. I was going to use the second one for parts, but now I see that there is a chance to get both running again.?
Jim?
|
Re: Analog vs Digital Oscilloscopes
On Thu, Jul 20, 2017 at 6:17 PM, Daniel Koller kaboomdk@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote: Fastest sweep on a 7104/7B10 is 200pS per division, x10 setting, so 20pS per division. It's actually 2ns/div unmagnified, or 200ps/div magnified.
|
Re: HP-3586B PS problem - connector J2 overheating
Thanks George,?
That's a sensible recommendation and I will follow through with it. I received another reply suggesting the same thing from another group member who also had this problem with his 3586B. I did think about the possibility last year when I saw that both units were experiencing overheating on J2, but then thought nothing could be that simple. Hi.?
How would HP know that their connectors would fail on this line of equipment 30 years later from ?overheating. It reminds me of the broken knobs on some HP microwave testers from the 80s that I acquired.. All those knobs seemed to just crumble and fall off after so many years. Nothing lives forever.?
Thanks for the reply and suggestion.?
Jim?
|
Re: 141T reference replacement..a cure??
My experiments scoping NE-2 ignition show that
(a) illumination does not reduce the firing voltage, and
(b) the smaller the difference between supply voltage and firing voltage, the longer it takes to fire.
Dark-effect-reduced tubes like the ZZ1000 contain Krypton-85 to supply free electrons which facilitate firing in total darkness.
These tubes age three ways.? First, the Kr-85 decays, with a half-life of about ten years.? Without it, the tube takes longer to fire when it's in the dark.? This lengthens the turn-on spike, and since it's rising all that time, it
amplifies it as well.
This effect can be counteracted by illuminating the tube.? Illumination which comes on when the supply is energized reduces the delay to a certain value which is still fairly large.? I don't know if it's enough.
Full-time illumination reduces the delay to a small value.? This is inconvenient, because it requires wiring from the mains side of the power switch.
That covers tubes that have failed only due to Kr-85 decay.
The second aging symptom is a rise in firing voltage.? The mechanism is a change in gas composition and pressure as electrode evaporation traps gas.? It progresses whenever the tube is running.? Since delay increases fast as headroom shrinks, even an illuminated tube will eventually fail.
The third aging symptom is a rise in operating voltage.? Someday it will go beyond adjustment range, but I believe that the firing voltage will become unacceptably high first.
You can measure the firing voltage in-circuit with a scope.? If it's out of spec - above 115V - then shining light is a stopgap even if it initially works.? Just put in a TL431.
|
Re: HP-3586B PS problem - connector J2 overheating
I had this same problem.
I ended up replacing the PCB connector first, just because I was worried about carbonization.
When the cable connector pins overheat the springs inside lose temper and get worse. They will also need replacement as they will never work properly again. If you look carefully you can see how they can be removed from the housing. Only remove the good contacts, don't bother with the overheated ones, they need to be replaced. You can get all the parts from Digikey or Mouser.
I paid a little extra and got gold plated pins, just to give me more confidence of a longer term fix.
Peter
toggle quoted message
Show quoted text
On 7/20/2017 8:23 PM, jim@... [hp_agilent_equipment] wrote:
Gentlemen,
I two HP-3586Bs that have gone down with essentially the same problem. One failed last year and the other one just yesterday. I attempted a year ago to clean both power supply boards of battery leakage as suggested by the group. One was worse than the other, but after using DeOxit with swabs, both boards looked OK. I could not visually find any actual damage to components or connections.
Both evidenced severe connector heating on J2, pins 1.2.3 and 9,10. I am assuming this secondary cause brought them both down. You can view three of the connectors at:
I've looked at the recommendations for troubleshooting in Service Group J, but this appears to go beyond those.
It would appear that my cleaning job on the PS boards did not solve the problem. So where should I looks next before I investigate further.
I most sincerely appreciate as usual the great expert assistance I always receive from this group when something HP is over my head.
Many thanks,
Jim
W3BH
|
Re: HP-3586B PS problem - connector J2 overheating
Hi Jim
These look like standard Molex connectors, whether .1" or .156" pitch I cannot tell from the images. These connectors rely on a single wiping face under spring pressure from themselves, when they get warm they fail, this appears to be what has occurred here, simply replace them.
These connectors can be had on fleabay or via your favourite supplier. The really stupid thing is that the pins are frequently used in parallel to obtain a higher current ratting, this does not work long term as one pin invariably has a lower resistance and takes the lions share of the current and overheats.
73 George G6HIG
________________________________________
From: hp_agilent_equipment@... <hp_agilent_equipment@...> on behalf of jim@... [hp_agilent_equipment] <hp_agilent_equipment@...>
Sent: 21 July 2017 00:23
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] HP-3586B PS problem - connector J2 overheating
Gentlemen,
I two HP-3586Bs that have gone down with essentially the same problem. One failed last year and the other one just yesterday. I attempted a year ago to clean both power supply boards of battery leakage as suggested by the group. One was worse than the other, but after using DeOxit with swabs, both boards looked OK. I could not visually find any actual damage to components or connections.
Both evidenced severe connector heating on J2, pins 1.2.3 and 9,10. I am assuming this secondary cause brought them both down. You can view three of the connectors at:
I've looked at the recommendations for troubleshooting in Service Group J, but this appears to go beyond those.
It would appear that my cleaning job on the PS boards did not solve the problem. So where should I looks next before I investigate further.
I most sincerely appreciate as usual the great expert assistance I always receive from this group when something HP is over my head.
Many thanks,
Jim
W3BH
|
HP-3586B PS problem - connector J2 overheating
Gentlemen,?
I two HP-3586Bs that have gone down with essentially the same problem. One failed last year and the other one just yesterday. I attempted a year ago to clean both power supply boards of battery leakage as suggested by the group. One was worse than the other, but after using DeOxit with swabs, both boards looked OK. I could not visually find any actual damage to components or connections.?
Both evidenced severe connector heating on J2, pins 1.2.3 and 9,10. I am assuming this secondary cause brought them both down. You can view three of the connectors at:?
I've looked at the recommendations for troubleshooting in Service Group J, but this appears to go beyond those.?
It would appear that my cleaning job on the PS boards did not solve the problem. So where should I looks next before I investigate further.?
I most sincerely appreciate as usual the great expert assistance I always receive from this group when something HP is over my head.?
Many thanks,
Jim W3BH
|
Re: Analog vs Digital Oscilloscopes
? ?Almost, but not quite. ?I don't know what the electron beam current of a 7104 CRT is. ?Let's assume 1 microamp (that's probably a low estimate), so 6.24E18 electrons per Coulomb ? x 1E-6 ?C/ s = 6.24E12 electrons per second. ?Fastest sweep on a 7104/7B10 is 200pS per division, x10 setting, so 20pS per division. ? 6.24E12 Electrons per sec x 20E-12 ?= 125 electrons per division.....
? Wow, you are right. ? It would be hard to resolve on a regular CRT and the MCP bins them and multiplies them of course, but it's almost discrete. ?However, the uncertainty principle will make sure that we can't predict when they leave the electron gun thus blurring any spots on the screen... ? Is there speckle on the the MCP CRTs?
? Dan
On Thursday, July 20, 2017, 4:32:45 PM EDT, Chuck Harris cfharris@... [hp_agilent_equipment] wrote:
?
Go fast enough, or small enough, and everything
becomes discrete.
That should light a fire!
For example, if you take a standard electron beam, ala
a CRT, and sweep the beam quickly enough, you can get to
a speed where the electron beam looks similar to what
you would have with a rapid fire BB gun.. Each electron
represented by a BB. The electrons will land in discrete
spots on the screen. The 7104, with its MCP, operates in
this region.
|
Re: OT: Spinner 7/16 DIN female gauge
Hi
Re APC7 collets I am also after a quantity
Might be an idea for a bulk purchase as I could
use 10 to 20??
?
Also after an APC 3.5 cable
?
Paul B
From:
hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...]
Sent: 20 July 2017 21:14
To: hp_agilent_equipment
Subject: [hp_agilent_equipment]
OT: Spinner 7/16 DIN female gauge
?
?
Would
this be of interest to anyone?
http://imgur.com/gallery/E64jD
It's in like new condition and loos
I'd like to trade for a N or APC gauge.
Also anyone have a good source for APC7 collets?
--
Bryan Fields
727-409-1194 - Voice
http://bryanfields.net
No virus found in this message.
Checked by AVG -
Version: 2016.0.8013 / Virus Database: 4779/14714 - Release Date: 07/20/17
|
Google for tektronix abcs of probes and download their classic 60 page primer. ? John K1AE ?
toggle quoted message
Show quoted text
From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
Sent: Thursday, July 20, 2017 3:09 PM
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Probe bandwidth? ? On 20 Jul 2017 17:50:21 +0000, you wrote:
>I am confused regarding the stated bandwidth of an oscilloscope probe.
>
>I thought that the bandwidth was computed from the input impedance, almost purely capacitive at high frequencies. as the frequency where the reactance drops to 50 Ohms.
50 ohms is not the magic point. It is on 50 ohm probes, though.
The oscilloscope input is standardized at 1 meg (for most scopes) and
somewhere between 15 and 25 pf (tek = 1/20, HP I think goes 1/17 on
some scopes).
The actual probe is not just a resistive voltage divider feeding a
resistive/capacitive load, it has some peaking networks and
compensation networks to optimize the equivalent (for Tek) pulse
response to the frequency response.
>
>This idea seems to work most of the time but I am seeing some probes with stated bandwidth somewhat higher. For instance I see some Chinese probes advertised as 100 MHz, 200 MHz, even higher, yet their input capacitance is still around 20 pF more or less.
I have Tek probes generally to 200 Mhz, although the cable length has
an effect. 1X probes have very low bandwidth, 10x have higher, and
some 100X probes have higher than that. Past about 200 Mhz, the
inputs go to 50 ohms and I forget the capacitance. You're dealing
with low impedance here, while a 10x 1 meg probe has a loading of
perhaps 4-5 pf in parallel with 10 megs, a 10x 50 ohm probe has a
loading effect of 500 ohms, not sure about the capacitance.
So my opinion is that the bandwidth is a combination of the peaking
networks, the cable capacitance, the scope capacitance, the probe's
stray capacitance and the effective capacitance of the actual dropping
resistor.
The 20 pf is just really the capacitance that the probe can be
adjusted to match.
NB: some HP probes can adjust to 20pf TEK inputs, and vice versa, but
don't depend on it. Wonder why they did that?
>
>Before you jump down my throat about how terrible Chinese stuff is, let's keep it at a technical level and explain just what bandwidth means so I can decide what to buy.
Equivalent pulse response. While TEK and HP probes are held to higher
standards, I'm not so sure about the few Chinese probes I have. You'd
probably do well to see if what you can get is available from multiple
vendors so you might be able to find spare parts as/if needed.
I suspect that if you found a Rigol brand probe, you might get a
higher quality than an unnamed brand. That said, the Chinese probes
will work, but I'd be tempted to look across the spectrum of the same
probe (if you can ID them) and pick the lowest bandwidth as reality.
>
>I see probes very cheap (not really rugged but still a good value) for various prices from around $4 to $13 but they appear to be the same, except for the bandwidth rating. How can this be?
They may be playing specmanship. Tektronix probes of different cable
lengths have different bandwidths. The bandwith is also limited by
the scope you're using it with.
>
>Since my use is very casual and I don't need to pay for high quality, this is a somewhat important question. And of course, after a few years they fall apart and I need to purchase again, but over my lifetime I don't usually get to where I have spent the same money as for a Tek or HP probe.
Had you considered the Tektronix (or perhaps HP if they did this)
modular probes? P6108 is a 10x, modular (can replace parts) probe, 2
meters, 100 Mhz, 13 pf loading, 10 megs loading. That is, the probe
looks like a 13 pf capacitor to ground in parallel with a 10 meg
resistor.
Ebay used is quite possible.
Just went through about 10 probes, all of the P6105/6/8 variety,
identical specs at 2 meters length. A similar switchable probe 1X/10X
has a load of 1 meg and 104 pf in the X1 position and 10 megs/13 pf in
the 10 x position.
Harvey
>
>Bob
>
|
Re: HP HIL system to lend or buy?
Hello Paul,
Sorry for the slow reply. I am taking this project on cause it's interesting, and I want to do some TMI work in a project where I am totally in control.
You are high on my list of testers, don't worry. I just bought a HP 16500B and am now waiting for delivery. But I would of course love any other stuff sent my way.
My head office is in Slovakia, but I also have an address in Austria!
Tam
--
With best regards
Tam HANNA (e-mailing on a BlackBerry Q10)
toggle quoted message
Show quoted text
On July 17, 2017 8:54:24 PM CEST, "'Paul Bicknell' paul@... [hp_agilent_equipment]" wrote:
?
Hi Tam
?
Thank you for taking this project on
I believe you will require some sort of
specification / design criteria could you post you torts on this Group for feed
back
?
Regarding sell or lend
anything
?
Setting you up with ?a 9000 computer system might be? a bit expensive
but something like a 70004 might be a way forward
?
The big question for any one to help is
your location
?
Paul? B??????????
South cost? UK
From:
hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...]
Sent: 17 July 2017 09:18
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] HP
HIL system to lend or buy?
?
?
Hello Folks,
just made the decision - I am going forward with the HP keyboard emulator.
Sadly, I dont have any HP HIL equipment in house. My question is, if
anyone of you is willing to sell or lend anything? I would gladly pay
shipping both ways for lending, and a lend fee.
Tam
No virus found in this message.
Checked by AVG -
Version: 2016.0.8013 / Virus Database: 4779/14697 - Release Date: 07/17/17
|
Re: Analog vs Digital Oscilloscopes
Go fast enough, or small enough, and everything
becomes discrete.
That should light a fire!
For example, if you take a standard electron beam, ala
a CRT, and sweep the beam quickly enough, you can get to
a speed where the electron beam looks similar to what
you would have with a rapid fire BB gun.. Each electron
represented by a BB. The electrons will land in discrete
spots on the screen. The 7104, with its MCP, operates in
this region.
Similarly, if you take a fast enough digital scope, with
a high resolution vertical ADC, it will be indistinguishable
from an analog scope. I'm talking about running at
0.1 x Nyquist, and a 10 or 12 bit ADC.
Even a cheap cell phone LCD/LED screen has resolutions that
might as well be continuous as far as the eye in concerned.
And, the eye, isn't continuous anyway, but rather has a
discrete field of rods and cones. Continuousness is an
illusion brought to you by your squishyware.
Digital scopes from the 70's, '80's, and '90s, and cheap
digital scopes from the 2000's were bad with aliasing, and
visible quantization of voltage levels, but the more modern
digital scopes available today, are pretty good.. It is only
when you get to the very fastest DSO's that you can still
see the quantization effects of old.
Food for thought.
-Chuck Harris
Dave McGuire Mcguire@... [hp_agilent_equipment] wrote:
toggle quoted message
Show quoted text
Others have explained this adequately so I will only add a voice of
agreement and some random additional thoughts.
First of all, they are fundamentally different instruments. One is
discrete while the other is continuous.
Over the years many things that undergone an analog -> digital
transition, from "old fashioned analog" to "newer, better digital".
That seems to be the root of the general affinity, especially amongst
youngsters, for digital oscilloscopes over analog ones. Digital is just
better, though they can never seem to tell you why, other than "Because
it's...DIGITAL!"
The other issue is availability. Most analog design is much harder
than most digital design (note to nit-pickers: I said MOST), and most
manufacturing of high-end analog hardware is a lot more expensive than
most manufacturing of high-end digital hardware. This has led
manufacturers to prefer to make and sell digital oscilloscopes over
analog ones. Digital oscilloscopes are a lot cheaper to design and
make, especially in China where manufacturing volume far exceeds
engineering talent.
One other issue, though in which direction the causality relationship
goes is debatable, is the demise of CRTs. CRTs are inherently
continuous devices, while LCDs (and most other flat-screen display
technologies) are inherently digital, or discrete, devices.
So, let's face it, graphing voltage against time is a process that was
essentially perfected a long time ago. The only thing we're really
optimizing for anymore in successive generations of oscilloscopes is
whiz-bang features (and we're running out of ideas for those) and profit
margins. Sure, there are ever-faster 50+GHz instruments, but those are
for very specialized applications that almost nobody actually uses, in
comparison to the rest of us...but in general, an oscilloscope made last
month does pretty much the same thing as an oscilloscope made twenty
years ago.
For a long while I've been at the point where I can put pretty much
any oscilloscope I want on my bench. I own probably thirty
oscilloscopes now (I have a "thing" for oscilloscopes!), but I regularly
use three on my "ordinary day-to-day work" bench: A Tek 2465A, a Tek
7854 with various plugins, and a Tek TDS3012. Which do I prefer? None!
I use the best tool for the job at hand, on a task-by-task basis.
Knowing the strengths, weaknesses, and capabilities of each of your
instruments is the key.
-Dave
On 07/20/2017 10:33 AM, bunge@... [hp_agilent_equipment] wrote:
Do digital 'scopes replace analog ones?
Perhaps this has been covered in which case I apologise.
I have a Tek 2467B and two of my friends have Tek 2465 'scopes, one of
which has a failed horizontal chip (see the Tek site). There do not
appear to be analog replacements for these 'scopes. I looked through HP
and Tek catalogs into the mid 1990's and see that HP dropped analog
'scopes completely and Tek does not show a replacement for the 2467B.
My experience in 1990 with a DSO was frustrating and, even knowing what
was there, I could not get a fast pulse pair to show on the DSO. It
showed sine waves. My HP54540 will display a fast pulse pair easily with
no confusion, so they have improved.
My question is if there is still a place for an analog 'scope? I use
mine all the time but I am obsolete.
If a digital 'scope will replace the Tek 2467B then which one would be a
good choice? What are people using t hese days and is there anything
affordable from the late 1990's?
Has anyone successfully replaced the horizontal chip on a Tek 2465/67
with a DIY board?
Has anyone got the Thomas Lafay PCB working? I will ask on the Tek site
as well.
|
OT: Spinner 7/16 DIN female gauge
Would this be of interest to anyone?
It's in like new condition and loos
I'd like to trade for a N or APC gauge.
Also anyone have a good source for APC7 collets?
--
Bryan Fields
727-409-1194 - Voice
|
Re: Experience with AliExpress for connectors
I can only testify that AliExpress is very benevolent when a complaint is filed through their system. Buy, try, chuck back if found bad.
Just make sure to ignore the whining from the seller...
--
With best regards
Tam HANNA (e-mailing on a BlackBerry Q10)
toggle quoted message
Show quoted text
On July 19, 2017 5:01:11 PM CEST, "'David C. Partridge' david.partridge@... [hp_agilent_equipment]" wrote:
?
I want to buy two Lemo connectors FGJ.2B.306.CLLD72Z
Problem is that Lemo want GBP19.24 each plus tax at 20% and have an MOV of
GBP100 plus tax (or a surcharge of GBP25 plus tax) with shipping on top.
I saw this page on AliExpress:
4-16-18/32802964953.html?spm=2114.search0104.8.60.UYHEap>
Offering them at a lower price than Lemo and seemingly offering small orders
and free shipping.
Are they OK to deal with or would I be throwing my money down a black hole?
Dave
|
|
|
On 20 Jul 2017 17:50:21 +0000, you wrote: I am confused regarding the stated bandwidth of an oscilloscope probe.
I thought that the bandwidth was computed from the input impedance, almost purely capacitive at high frequencies. as the frequency where the reactance drops to 50 Ohms. 50 ohms is not the magic point. It is on 50 ohm probes, though. The oscilloscope input is standardized at 1 meg (for most scopes) and somewhere between 15 and 25 pf (tek = 1/20, HP I think goes 1/17 on some scopes). The actual probe is not just a resistive voltage divider feeding a resistive/capacitive load, it has some peaking networks and compensation networks to optimize the equivalent (for Tek) pulse response to the frequency response.
This idea seems to work most of the time but I am seeing some probes with stated bandwidth somewhat higher. For instance I see some Chinese probes advertised as 100 MHz, 200 MHz, even higher, yet their input capacitance is still around 20 pF more or less.
I have Tek probes generally to 200 Mhz, although the cable length has an effect. 1X probes have very low bandwidth, 10x have higher, and some 100X probes have higher than that. Past about 200 Mhz, the inputs go to 50 ohms and I forget the capacitance. You're dealing with low impedance here, while a 10x 1 meg probe has a loading of perhaps 4-5 pf in parallel with 10 megs, a 10x 50 ohm probe has a loading effect of 500 ohms, not sure about the capacitance. So my opinion is that the bandwidth is a combination of the peaking networks, the cable capacitance, the scope capacitance, the probe's stray capacitance and the effective capacitance of the actual dropping resistor. The 20 pf is just really the capacitance that the probe can be adjusted to match. NB: some HP probes can adjust to 20pf TEK inputs, and vice versa, but don't depend on it. Wonder why they did that?
Before you jump down my throat about how terrible Chinese stuff is, let's keep it at a technical level and explain just what bandwidth means so I can decide what to buy.
Equivalent pulse response. While TEK and HP probes are held to higher standards, I'm not so sure about the few Chinese probes I have. You'd probably do well to see if what you can get is available from multiple vendors so you might be able to find spare parts as/if needed. I suspect that if you found a Rigol brand probe, you might get a higher quality than an unnamed brand. That said, the Chinese probes will work, but I'd be tempted to look across the spectrum of the same probe (if you can ID them) and pick the lowest bandwidth as reality.
I see probes very cheap (not really rugged but still a good value) for various prices from around $4 to $13 but they appear to be the same, except for the bandwidth rating. How can this be?
They may be playing specmanship. Tektronix probes of different cable lengths have different bandwidths. The bandwith is also limited by the scope you're using it with.
Since my use is very casual and I don't need to pay for high quality, this is a somewhat important question. And of course, after a few years they fall apart and I need to purchase again, but over my lifetime I don't usually get to where I have spent the same money as for a Tek or HP probe.
Had you considered the Tektronix (or perhaps HP if they did this) modular probes? P6108 is a 10x, modular (can replace parts) probe, 2 meters, 100 Mhz, 13 pf loading, 10 megs loading. That is, the probe looks like a 13 pf capacitor to ground in parallel with a 10 meg resistor. Ebay used is quite possible. Just went through about 10 probes, all of the P6105/6/8 variety, identical specs at 2 meters length. A similar switchable probe 1X/10X has a load of 1 meg and 104 pf in the X1 position and 10 megs/13 pf in the 10 x position. Harvey
Bob
|
High frequency probes use resistive, low capacitance cable and more complex compensation circuits.
What the difference between the various chinese models is I don't know.
Robert G8RPI
|
Re: Analog vs Digital Oscilloscopes
Others have explained this adequately so I will only add a voice of
agreement and some random additional thoughts.
First of all, they are fundamentally different instruments. One is
discrete while the other is continuous.
Over the years many things that undergone an analog -> digital
transition, from "old fashioned analog" to "newer, better digital".
That seems to be the root of the general affinity, especially amongst
youngsters, for digital oscilloscopes over analog ones. Digital is just
better, though they can never seem to tell you why, other than "Because
it's...DIGITAL!"
The other issue is availability. Most analog design is much harder
than most digital design (note to nit-pickers: I said MOST), and most
manufacturing of high-end analog hardware is a lot more expensive than
most manufacturing of high-end digital hardware. This has led
manufacturers to prefer to make and sell digital oscilloscopes over
analog ones. Digital oscilloscopes are a lot cheaper to design and
make, especially in China where manufacturing volume far exceeds
engineering talent.
One other issue, though in which direction the causality relationship
goes is debatable, is the demise of CRTs. CRTs are inherently
continuous devices, while LCDs (and most other flat-screen display
technologies) are inherently digital, or discrete, devices.
So, let's face it, graphing voltage against time is a process that was
essentially perfected a long time ago. The only thing we're really
optimizing for anymore in successive generations of oscilloscopes is
whiz-bang features (and we're running out of ideas for those) and profit
margins. Sure, there are ever-faster 50+GHz instruments, but those are
for very specialized applications that almost nobody actually uses, in
comparison to the rest of us...but in general, an oscilloscope made last
month does pretty much the same thing as an oscilloscope made twenty
years ago.
For a long while I've been at the point where I can put pretty much
any oscilloscope I want on my bench. I own probably thirty
oscilloscopes now (I have a "thing" for oscilloscopes!), but I regularly
use three on my "ordinary day-to-day work" bench: A Tek 2465A, a Tek
7854 with various plugins, and a Tek TDS3012. Which do I prefer? None!
I use the best tool for the job at hand, on a task-by-task basis.
Knowing the strengths, weaknesses, and capabilities of each of your
instruments is the key.
-Dave
toggle quoted message
Show quoted text
On 07/20/2017 10:33 AM, bunge@... [hp_agilent_equipment] wrote:
Do digital 'scopes replace analog ones?
Perhaps this has been covered in which case I apologise.
I have a Tek 2467B and two of my friends have Tek 2465 'scopes, one of
which has a failed horizontal chip (see the Tek site). There do not
appear to be analog replacements for these 'scopes. I looked through HP
and Tek catalogs into the mid 1990's and see that HP dropped analog
'scopes completely and Tek does not show a replacement for the 2467B.
My experience in 1990 with a DSO was frustrating and, even knowing what
was there, I could not get a fast pulse pair to show on the DSO. It
showed sine waves. My HP54540 will display a fast pulse pair easily with
no confusion, so they have improved.
My question is if there is still a place for an analog 'scope? I use
mine all the time but I am obsolete.
If a digital 'scope will replace the Tek 2467B then which one would be a
good choice? What are people using t hese days and is there anything
affordable from the late 1990's?
Has anyone successfully replaced the horizontal chip on a Tek 2465/67
with a DIY board?
Has anyone got the Thomas Lafay PCB working? I will ask on the Tek site
as well.
--
Dave McGuire, AK4HZ
New Kensington, PA
|
I am confused regarding the stated bandwidth of an oscilloscope probe. I thought that the bandwidth was computed from the input impedance, almost purely capacitive at high frequencies. as the frequency where the reactance drops to 50 Ohms. This idea seems to work most of the time but I am seeing some probes with stated bandwidth somewhat higher.? For instance I see some Chinese probes advertised as 100 MHz, 200 MHz, even higher, yet their input capacitance is still around 20 pF more or less. Before you jump down my throat about how terrible Chinese stuff is, let's keep it at a technical level and explain just what bandwidth means so I can decide what to buy. I see probes very cheap (not really rugged but still a good value) for various prices from around $4 to $13 but they appear to be the same, except for the bandwidth rating.? How can this be? Since my use is very casual and I don't need to pay for high quality, this is a somewhat important question.? And of course, after a few years they fall apart and I need to purchase again, but over my lifetime I don't usually get to where I have spent the same money as for a Tek or HP probe. Bob
|
Re: OT: Anyone in UK (or Europe) likely to be placing an order with Lemo in the near future
toggle quoted message
Show quoted text
From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
Sent: 20 July 2017 12:21
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: OT: Anyone in UK (or Europe) likely to be placing an order with Lemo in the near future? ?? requesting a sample.
|
Paul Bicknell
John Allen
Cubdriver
Dave McGuire
David C. Partridge