Re: What happened to HP/Agilent detailed circuit schematics
Why am I here? Possibly to teach guys like you that modern equipment isn't always economical for guys like you and me to repair. Companies providing schematics wouldn't change that fact one iota. -Chuck Harris On Mon, 26 Aug 2024 14:55:34 -0700 "Frank Mashockie" <fmashockie@...> wrote: This entire group is only possible because HP/Agilent for a time used
to provide schematics.? They still provide service manuals as far as
I am aware.? That is all proponents of right to repair are asking
for.? To prevent the manufacturers from monopolizing the repair
market.? And to allow consumers to repair the things they bought
themselves however they would like.? If you don't agree with that,
then why are you in this group Chuck?
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Re: What happened to HP/Agilent detailed circuit schematics
Sadly, I didn't think you would understand... I inferred your desire to share in proprietary manufacturing processes from what you were asking. Programming a custom chip is a part of the manufacturing process (just like forging a tungsten filament). It requires specialized equipment, and specialized knowledge that most are incapable of understanding even if it is spoon fed to them. We think nothing of replacing the whole light bulb, when the filament burns out (although that hasn't always been the case)... Why is it so hard to understand that like a light bulb, a modern circuit board can also be uneconomical to repair? -Chuck Harris On Mon, 26 Aug 2024 14:46:49 -0700 "Frank Mashockie" <fmashockie@...> wrote: Nice try smart ass.? Where did I say share their manufacturing
process?
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Re: What happened to HP/Agilent detailed circuit schematics
I am a hobbyist and also a professional in engineering who has for decades made purchasing decisions.? In my career I have leaned toward buying equipment that is supportable.? Yes now that is getting very rare but in the past it meant a lot of business went to HP/Agilent due to their extensive documentation.? While I was not at huge companies that business still added up to millions of dollars and that documentation was often what tipped the scales.? The HP salespeople I talked to told me I was certainly not the only one who felt that way.
The worst these days is equipment which requires proprietary software to even swap a module, and that software is factory-only with some manufacturers.? When support ends you throw the equipment out as it is worthless even as a parts mule.
Peter
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On 8/26/2024 10:10 PM, pianovt via groups.io wrote: On Mon, Aug 26, 2024 at 01:00 PM, Frank Mashockie wrote:
As consumers, repairs, or designers we shouldn't allow manufacturers to
continue these repair prevention strategies that ultimately stifle the
sharing of information and community knowledge.
Frannk,
I can speak about this topic from all the vantage points you mentioned. I am a consumer, I do like to repair some of my equipment (but not all), I have designed test equipment at HP, and I own a manufacturing business.
I can assure you that engineers at HP/Agilent/Keysight never spent any time pondering "sharing of information and community knowledge". That just isn't anything that ever crossed our minds. I/we did spend a lot of time thinking about how to make troubleshooting efficient for a service technician. Increasingly, the best solution is to tell the technician how to identify the defective assembly and just swap it because repair requires special tools or knowledge that I could not reasonably expect a technician to have. Most HP/Agilent/Keysight products contain at least one, but often several novel or clever ideas in them. Remember that Keysight at any one time has thousands of supported products.
Nowadays, assembly level repair is in most cases the most efficient repair method. Troubleshooting down to component level is prohibitively expensive. Keep in mind that HP/Agilent/Keysight is using a different business model than, say, Heathkit (which went out of business). Companies that buy equipment want reliable products with minimal down-time. The engineers working at those companies may or may not be enhusiastic hobbyists when they go home, but they are not the ones paying for the equipment.
Finally, consider the implications of Keysight publishing the schematics for a LCD display or power supply which is purchased form an outside vendor. It's hard enough to find a good supplier without asking them to release documentation for the "sharing of information and community knowledge".
Vladan
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Re: What happened to HP/Agilent detailed circuit schematics
On Mon, Aug 26, 2024 at 01:00 PM, Frank Mashockie wrote:
As consumers, repairs, or designers we shouldn't allow manufacturers to continue these repair prevention strategies that ultimately stifle the sharing of information and community knowledge.
Frannk,
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I can speak about this topic from all the vantage points you mentioned. I am a consumer, I do like to repair some of my equipment (but not all), I have designed test equipment at HP, and I own a manufacturing business.
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I can assure you that engineers at HP/Agilent/Keysight never spent any time pondering "sharing of information and community knowledge". That just isn't anything that ever crossed our minds. I/we did spend a lot of time thinking about how to make troubleshooting efficient for a service technician. Increasingly, the best solution is to tell the technician how to identify the defective assembly and just swap it because repair requires special tools or knowledge that I could not reasonably expect a technician to have. Most HP/Agilent/Keysight products contain at least one, but often several novel or clever ideas in them. Remember that Keysight at any one time has thousands of supported products.
?
Nowadays, assembly level repair is in most cases the most efficient repair method. Troubleshooting down to component level is prohibitively expensive. Keep in mind that HP/Agilent/Keysight is using a different business model than, say, Heathkit (which went out of business). Companies that buy equipment want reliable products with minimal down-time. The engineers working at those companies may or may not be enhusiastic hobbyists when they go home, but they are not the ones paying for the equipment.
?
Finally, consider the implications of Keysight publishing the schematics for a LCD display or power supply which is purchased form an outside vendor. It's hard enough to find a good supplier without asking them to release documentation for the "sharing of information and community knowledge".
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Vladan
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HP 141T Power Supply Help Needed
Good Evening to the group!? ?First post but I've been reading a ton for a few weeks now.? ?
(I thought I posted this but I don't see it, so I'm reposting.. please delete if i did something dumb)?
I've got a 141T with a 1615a prefix.? It's power supply was a mess when I got it,?
almost every fuse was blown and most supply's were measuring high.? ?I replaced the?
V1 regulator tube with a string of diodes and began debugging more.? It seems like most?
of the drivers and differential amps were having _some_ problem.? ?I've measured most of?
the transistors out of circuit and replaced with parts as recommended by other posts.? ?
At this point, I've got improved but still not great results. I've checked passives as best I can and I have measured
around the transistors a bit.? Obviously trying not to blow anything up with the tight confines of the A2 board.? ?
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With the supply wires on the left removed to the rest of the unit, general voltages are as follows:?
* +102v which seems decent
* about -82v instead of -100v
* 300v instead of 248v, if it were tubes I'd almost expect this with an unloaded supply but I don't think I do expect it here.?
* -1.5v instead of -12.6v.? ?
Acknowledging the dependencies between supplies, I'm starting at the -100v supply since +100 looks "ok" (for now at least).??
In the affected supplies, I "believe" all transistors and resistors are good but some of the zeners measure a little funky (maybe).??
Looking for guidance or advice to break down the problem a bit and work through it.? ? ?
TIA, Bill - WW1H?
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Re: HP8566B - Making sense of the figures
Congratulations Jinxie, your hard work and determination paid off. Your dual transistor construction looked great and will be an inspiration for others. I also enjoyed the challenge, no need for any gift. If you feel you have to do something you can make a small donation to a local animal shelter or charity.?
Ozan
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On Mon, Aug 26, 2024 at 10:23 AM, Jinxie wrote:
Indeed, and I've just done it. No sign of any YTO warning and the FM stations are back where they should be, too. I think we can call that a successful outcome, Ozan!
I'm extremely grateful for your knowledge and persistence in getting this thing back into fully working order again. No way could I have done it without you, that much at least is certain. Do you have a Paypal account? If so, PM me your particulars and I'll send you a 'drink' as we say as a gesture of my sincere gratitude for your guidance and expertise. Well done!
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Re: HP8566B - Making sense of the figures
Thank you for the nice words Barry. I can assure you no computers were harmed during the debug :) I like the puzzle of hunting for the fault, especially on older HP and Tek equipment where there is excellent schematics and documentation. However, as I repaired more equipment my bench and garage space started filling up. This is best of both worlds, I still enjoy the debug and I don't have to think about where to store the equipment afterwards.
Ozan
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On Mon, Aug 26, 2024 at 10:42 AM, n4buq wrote:
I have trouble convincing myself that Ozan isn't an advanced computer sent here from the 23rd century.? He has an amazing wealth of knowledge and so willing to help with all sorts of trouble-shooting.? I don't know how he does it but I'm very glad he does.
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Congratulations on the repair!
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Barry - N4BUQ
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Indeed, and I've just done it. No sign of any YTO warning and the FM stations are back where they should be, too. I think we can call that a successful outcome, Ozan!
I'm extremely grateful for your knowledge and persistence in getting this thing back into fully working order again. No way could I have done it without you, that much at least is certain. Do you have a Paypal account? If so, PM me your particulars and I'll send you a 'drink' as we say as a gesture of my sincere gratitude for your guidance and expertise. Well done!
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Re: HP8566B - Making sense of the figures
@jmr
Thanks for the suggestion; I guess now - or nowish - would be optimal. If I can find the time tomorrow I shall do so (but it will definitely be under a new subject title as this thread has definitely got waaayyyy too long!!)
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Re: What happened to HP/Agilent detailed circuit schematics
I think group member Milan Vasic has some CLIP files (Component Level Information Packet) that contain schematics for various HP gear including the ESGD B variants of these signal generators. These are proper schematics and they are not in the service manual. HPAK do sometimes release CLIP info into the wild, but sadly not often enough.
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I'm not sure if there will be much difference in the display between A and B variants so it might be OK to work with the B schematics in your case?
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There's an example CLIP here that shows part of the display for the B variants for example:
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This may be of some use but Milan Vasic may have something more relevant?
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In case it is of any interest, my D4000A was running very early firmware when I bought it and the firmware had a nasty bug that showed up when doing an IQ calibration. Instead of muting the RF output it briefly turned the output to full unlevelled and this could get close to +20dBm. This could be enough to damage some test gear. This was not a nice feature...
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I upgraded to later firmware and this seemed to cure this issue. I just checked and the latest firmware and the loader SW is still available on the Keysight website.
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Re: What happened to HP/Agilent detailed circuit schematics
That assumes you have the time to reverse engineer the faulty product, at least to some degree.? These days I'm commuting about two and a half hours each day, so not having at least a schematic usually prevents me from being able to repair much of anything.? ? ? ? ?Jim
On Mon, Aug 26, 2024 at 3:09 PM, Frank Mashockie <fmashockie@...> wrote: I agree there Jim.? While I do agree with some legislation, I have not been too keen on what I've seen passed so far.? Manufacturers are already circumventing some of these laws passed in CA from what I've heard.? I should have clarified that the best way to thwart manufacturers is groups like this, forums, YouTube content creators and bloggers.? If anything, the lack of service manuals and schematics has made me a better problem solver and critical thinker in my own work (or at least I think lol).? ?
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Re: What happened to HP/Agilent detailed circuit schematics
I agree there Jim.? While I do agree with some legislation, I have not been too keen on what I've seen passed so far.? Manufacturers are already circumventing some of these laws passed in CA from what I've heard.? I should have clarified that the best way to thwart manufacturers is groups like this, forums, YouTube content creators and bloggers.? If anything, the lack of service manuals and schematics has made me a better problem solver and critical thinker in my own work (or at least I think lol).? ?
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Re: What happened to HP/Agilent detailed circuit schematics
As usual, something between the ridiculous extremes would be the best situation.? Between say, manufacturers being forced by the government to divulge all their secrets and consumers forced to have every single product returned to the mfr for repair.? ? ? ? ? Jim Ford, Laguna Hills, California, USA?
On Mon, Aug 26, 2024 at 2:55 PM, Frank Mashockie <fmashockie@...> wrote: This entire group is only possible because HP/Agilent for a time used to provide schematics.? They still provide service manuals as far as I am aware.? That is all proponents of right to repair are asking for.? To prevent the manufacturers from monopolizing the repair market.? And to allow consumers to repair the things they bought themselves however they would like.? If you don't agree with that, then why are you in this group Chuck???
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Re: What happened to HP/Agilent detailed circuit schematics
This entire group is only possible because HP/Agilent for a time used to provide schematics.? They still provide service manuals as far as I am aware.? That is all proponents of right to repair are asking for.? To prevent the manufacturers from monopolizing the repair market.? And to allow consumers to repair the things they bought themselves however they would like.? If you don't agree with that, then why are you in this group Chuck???
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Re: What happened to HP/Agilent detailed circuit schematics
Nice try smart ass.? Where did I say share their manufacturing process???
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Re: What happened to HP/Agilent detailed circuit schematics
Does the customer deserve information on how to repair an incandescent light bulb? Perhaps the customer should be given access to cheap replacement tungsten filaments? Or, if that isn't practical, instructions on how they mixed and forged tungsten? Should the manufacturer be required to include a service port on each light bulb to make the filament reachable without damage? -Chuck Harris On Mon, 26 Aug 2024 13:00:01 -0700 "Frank Mashockie" <fmashockie@...> wrote: Razvan,
Your points are valid, but my point is don't give the manufacturers
the benefit of the doubt.? The customer deserves this information.? I
apologize as I came off a bit strong with my wording.
Unless the MCU has failed completely, I've ran into many cases where
only a GPIO pin or two has gone bad.? In these cases, flashing the
MCU is still an option.? As long as it isn't read protected (you'd be
surprised how many manufacturers don't, especially on older
equipment).? Or by sharing firmware of MCUs you've flashed with
communities like this (or EEVBlog), all you need is a new MCU to
perform the programming.? Sure it may take some additional tools, but
it is pretty easy in most cases.
As consumers, repairs, or designers we shouldn't allow manufacturers
to continue these repair prevention strategies that ultimately stifle
the sharing of information and community knowledge.? We shouldn't
give them the benefit of the doubt that it is acceptable to forgo
sharing of schematics just because the equipment has an MCU or FPGA.
That doesn't stop manufacturers from protecting their creations
either.? For example, in pharma, a drug can be patented, yet we still
know the chemical composition.? It is not kept secret; the entire
public knows.? It should be no different for electronics.
-Frank
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Re: What happened to HP/Agilent detailed circuit schematics
Razvan,
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Your points are valid, but my point is don't give the manufacturers the benefit of the doubt.? The customer deserves this information.? I apologize as I came off a bit strong with my wording.?
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Unless the MCU has failed completely, I've ran into many cases where only a GPIO pin or two has gone bad.? In these cases, flashing the MCU is still an option.? As long as it isn't read protected (you'd be surprised how many manufacturers don't, especially on older equipment).? Or by sharing firmware of MCUs you've flashed with communities like this (or EEVBlog), all you need is a new MCU to perform the programming.? Sure it may take some additional tools, but it is pretty easy in most cases.??
?
As consumers, repairs, or designers we shouldn't allow manufacturers to continue these repair prevention strategies that ultimately stifle the sharing of information and community knowledge.? We shouldn't give them the benefit of the doubt that it is acceptable to forgo sharing of schematics just because the equipment has an MCU or FPGA.? That doesn't stop manufacturers from protecting their creations either.? For example, in pharma, a drug can be patented, yet we still know the chemical composition.? It is not kept secret; the entire public knows.? It should be no different for electronics.?
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-Frank
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Re: HP8510C VNA, read LIF DD floppy, initialize HD floppy? Using FlashFloppy or other emulator
Hello,
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Thanks for the suggestions!
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Tom: I don't have a GPIB based floppy drive, but I believe the method only shifts the problem one step? Maybe I'm missing something?
I have (I believe I have) images of floppies that I have dumped using an Arduino. When reading these images from a floppy emulator (FlashFloppy, Keir Fraser, v 3.39) I the same dump as when reading the real floppy.?
When running FlashFloppy as the drive in the HP8510C, the HD disks (1232 kB) work to read and write, but the DD disks (616 kB) are just refused although the real floppy is read without problem when a physical drive is installed.
Although I can read and write into the image of the HD floppy, the HP8510C refuses to initialize the HD image. It tries to access tracks up to 79, which is 'outside' the normal image, but even with a huge image (160 tracks...), init won't work.
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Denys: Thanks for setting up the repository! I have some images that may be of interest. However, I can't read the .hfe files (images). Mine (.img) are exactly the size of the floppy data content and is basically a raw dump, but the .hfe files you have seem to be different. You are using FlashFloppy 3.41 whereas I run 3.39 - could this be the reason or how should one interpret the .hfe files?
I'm also looking for the IMG.CFG - would be great if you could add that. Do you know of a format for the DS DD (6126 kB) floppy??
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Regards,
? Staffan
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Re: What happened to HP/Agilent detailed circuit schematics
I've got three of the ESGD series sig gens here and so far, none of the backlights have failed. However, it is only a matter of time before each one fails. The oldest one is an ESGD4000A. This was an ex-rental I purchased about 10 years ago. It already had a lot of run time hours and it is up to 78,000 hours now. It may be that the display backlight has already been repaired in the past as it has been run for so many hours.
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So far it has proved to be completely reliable. I don't recall having to repair it. The other two ESGD sig gens have had problems, the worst being an E4433B. I've had to repair this numerous times. The MMIC devices used in the signal path are prone to failure and also some of the memory chips in the UND dual arb board needed to be replaced. The PSU failed in the E4438C. The PSU used in the E4438C is huge and very complicated, but it proved easy to repair. I don't have schematics for any of these sig gens but managed to repair them quickly and easily for little cost.
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I converted an old Aeroflex 3414 sig gen display to an LED backlight recently with great success. Hopefully, the ESGD sig gens will be as easy to convert?
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Re: HP8566B - Making sense of the figures
Agreed. This was a good read and a great outcome. Well done to all involved!
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If it helps, I can suggest a few performance tests that may be relevant now.
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To test that the loop gain switch (at Q4A and Q4B) is performing OK, try posting up screen shots of the 8566B measuring its 100MHz cal output on a 20kHz span, a 50kHz span and a 100kHz span.
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I think that this should show if the loop gain is changing correctly as an increase in loop gain should deliver an increase in loop bandwidth on the narrow span. It should be possible to spot this by looking at the phase noise response on the three different spans.
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Also, increase the span to 6MHz and have a look to see how stable the response is at the centre of the display. There is usually a small amount of wobble in the swept trace and this is fairly normal as the analyser switches to lock and roll mode for spans over 5MHz. If the wobble is excessive, then maybe some other aspect of the loop has a minor problem.
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Re: What happened to HP/Agilent detailed circuit schematics
Hello Frank,
From your point of view maybe it is short-sighted but I encountered
issues in the past where we had some Altera and Atmel ICs that was
faulty including other passive components around them and we replaced
all of them with new parts but the system wouldn't work. Contacting
manufacturer didn't help. They don't share the files to rebuild the
equipment and since we repaired it they don't want to accept it for
repair also.
In theory you can repair everything but in reality you cannot do it.
Most test equipment now is running some custom PC board that in theory
can be repaired but if some NAND flash is damaged and you cannot get the
full firmware how you will fix it? Most vendors will say it is
"proprietary" code or what ever and they will not provide it to you.
What I would like to have is the PSU schematics at least. I saw a lot of
new test equipment with PSUs broken/fried and many of those PSUs were
very complex full with SMD components.
Maybe you can share more details related to fixing modern test equipment
to understand the complexity.
Regards,
Razvan
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On 26.08.24 17:45, Frank Mashockie via groups.io wrote: Dave, Also this comment below is probably the most short-sighted and
completely ridiculous.? There is still much repair you can do without
having access to the firmware.? Although I believe companies should
offer that, too.
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Jinxie
Frank Mashockie