HP 8082A Pulse Generator Repair Part 3: Ersatz ECL Fabrication and Pulser Repair
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- Опубликовано: 20 окт 2024
- We design a surface mount PCB for our ECL gate replica. After getting it the PCB fabricated by our sponsor PCBWay ( www.pcbway.com ) it's time to build, debug and test the circuit, which as usual doesn't go quite as planned. Finally, we try it in our pulser, and see if we can fully repair it.
Project PCB and BOM uploaded on PCBWay:
www.pcbway.com...
The files of the project and complete documentation are on my web site:
www.curiousmar...
Our sponsor for PCBs: www.pcbway.com
Support the team on Patreon: / curiousmarc
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Learn more on the companion site: www.curiousmar...
Contact info: www.youtube.co...
11:14 You know you have a serious piece of test gear when your plug-in modules have plug-in modules.
You are my motivation to go back to university. I dropped out because I was tired of studying and just wanted a job, but looking back at my life right now that was the worst decision I've ever made. I will enroll and keep going. Thanks for being a massive inspiration.
Good luck, Paolo!
rjy8960 Thanks mate!
Knowledge is everything
Good luck. This helps me stay motivated when online class stinks
The world of RF design where capacitance and inductance are stowaways and the ground ain’t right too! Amazing results and a quality repair mod that does not look out of place. Well done!
ah, the old "pay to suffer" software model.
Aka enterprise software
I'm mot ready to talk about my relationship with Maximo.
Any sufficiently antiquated technology is indistinguishable from magic.
Never knew that "Ersatz" is also used in english. You learn something new every day
How I loved those modular Tek scopes when I was working on some ECL designs back in my university days. I worked at Motorola semiconductors, using their ECLiPS parts (for ECL in picoseconds). We were trying to build a stop clock that had a least bit accuracy of 20.5ps to be used in the test jigs we had.
Fascinating times. Thanks for the memory.
Weren’t they great? I have a paper from my Bell Labs days from research on laser diode high speed effects that were only visible in sufficient detail to be studied on that scope.
I don't follow but a little of what you are talking about, but it still somehow manages to fascinate me. Your analysis is so soothing. It's also inspired me to make the simplest circuit possible, understanding why the first transistors that came with my Arduino starter kit I used for powering 12v RGB LED strips didn't light up and why I needed something like a TIP 120. And then as I read more, it dawned on my finally the difference between these and FETs. Something I have heard and read about, but never quite grocked. I still am in awe of anyone who can design such a complicated machine. You are a good presenter and I thank you for your generous sharing!
The transistors you got surely could power those strips but if they were overloaded they would get hot and eventually emit the magic smoke perhaps. But if the transistors did nothing then they were not used in a proper circuit, and I bet if you shared with us what part the transistors were, me or someone else could tell you how to hook them up to make them work. When it comes to an RGB LED strip, most common transistors can control them and it doesn’t matter whether it’s a mosfet or a bipolar :)
I love the modularity of that scope! So satisfying to see you clip in different modules and then the mini module in the big one.
reckon that must have been a decent fraction of a million dollars worth of kit when new on that cart lol
These old Tek scopes were truly marvelous creations, and pleasant to use.
@@zyeborm The 7854 was $10,500 in 1981
@@taunusmechanics3121 That's 25k in today dollars.
I hate to admit my age that I actually used that very pulse generator in some of my very first designs. By the way it did go out twice while I used it over two years thank God for HP and repair.
Never have seen ECL logic re-created from transistors. Loved the series! Lots of tidbits.
Never underestimate the creativity of an engineer when a company refuses to provide parts or info they need.
30+ years experience as an electronics design engineer and I still maintain RF is Black Magic!
25 years experience with electronic CAD software and I fully understand your comment about Eagle ...
With KiCad’s wonderful progress there’s no sane reason to use Eagle anymore. Thankfully.
I love your videos even the ones that are beyondmy very amateur understanding. Thank you
I delight in watching these.
I've a PhD in maths and electronics but watching CuriousMarc my viewing goes: Yes.. Yes.. OK, yes.. Hrm.. if you say so.. I guess it's just magic.. Oh, BLACK magic, why didn't you say so?
I am really impressed about your simplified RF design approach with excellent practical circuitry replacement the original ... Hats Off to you Monsieur Marc ...
KiCAD also has a tool included called PCB-Calculator to calculate the width for impedance matched transmission lines on PCBs.
But is attrocious like the said Eagle. Use different tools, such as the Saturn PCB Toolkit.
Sixta16 It is at least very simple code to change. That wizard can be improved in an afternoon and I do suggest you have a go at it first. Otherwise I’ll have to get a pulled request ready. It’s fairly fun code to work with.
"I am not an RF engineer." It doesn't show! Your board design is about 10,000 times better than I would have done.
Very nice solution for this repair. Good tactic on designing the PCB also. This was fun to watch. Love these videos.
Terrific Marc. I watched all three parts, great fun. Thank you. Randall Buck
Marc
A very nice repair.
I had to smile. As a radio amateur who tries to dapple in the very short wave lengths, I have tried to build the occasional super neat 'professional' looking project. After all the planning and plotting and the soldering of all those grains of sand on the board I then find that it doesn't work as expected. By the time it does work, I have little pyramids of caps and resistors. I have occasionally had to resort to the odd vertical extension. I will copy your solution multiple boards for multiple versions.
Thanks for the best nerd channel on RUclips.
Steve M0KOV
That modular system is so awesome.
Magic vintage machines. Love them. I had same problem with HP 5340A 18 Ghz counter. I’ve been luky enough to find a good replacement board, but if I’ll face in the future the same problem you will be my bench-Marc 😬👍👍
Hahaha! Bench-Marc’ing. I like that. I might re-use it!
👍👍
I used KiCAD a few months ago for my first circuit boards - double sided - and I found it easy to use and the boards came out great. You are in another league, doing an RF circuit. I love seeing you use the old Tek scopes - I started at GE in 1983 and we had several of them. Sweet pieces of equipment.
That was a great repair! Marc, thanks for share with us all of this equipment. If it wasn't because of your channel I would not have the chance to know and admire vintage engineering equipment.
21:10 "Repaired fully.... the hard way". I disagree here.... It's been repaired the FUN way ;-)
I think it’s been repaired the ONLY way that resembles the hp way :)
The Tektronix is the most beautiful Oscilloscope I have ever seen!
Very nice series. I have way more respect for that pulse generator. I always thought they were way too big and limited. Had one on my bench for a while when I worked at HP.
A satisfying engineering challenge and resurrection. Thanks for bringing us along for the journey, Marc!
Very good I am happy for you CuriousMarc, you managed to get your HP 8082A Pulse Generator! This makes the world a better place!
Your pre-heating method is very useful. Sometimes I face a situation where the component heats up faster than the PCB when using hot air, and when it reaches the point, the solder is sucked by the component pin and even flows out from the pad on the PCB. I've had a few false joints that weren't soldered at all, especially with tiny packages like the SOT553 or larger packages like SOT23-6. A common feature is that these defects always seem to happen with ground pads. In those situations, your pre-heating method would save my day.
Takes me back to my time in the microwave industry, 1975 to 1985. Circuits were gold microstrip on alumina, and components stuck on with gold epoxy. Things have changed a lot since then!!!
Wow! Gold epoxy!
Doctor Curious saved another patient! 0.O
Stunning job, Sire!
The sort of wizardry that amuse the people. Please, more! Encore!!
Thank you for sharing the repair. Increible what you did with reverse ing of the chip the time and patience it took. I'm hooked
Bravo, never have I subscribed to a channel and had it deliver so immediately.
Excellent job. There must be many of these units out there needing a fix like this.
Those RF stuff is magic outside of this world. When I first time got some dead ka-band satellite transeiver and opened it for fun I was fascinated looking at its pcb. So much magic with tracing which forming strange elements... abosolutely mindblowing stuff! It's like some weird alien technology.
Excellent work. I learn a lot from these fault finding video's, thanks....DA
Great video series! I hate that feeling when you need a replacement part and it's "obsolete-unobtainium".
Impressed how well you are on top of this stuff.
Wonderful repair-adventure! It's also interesting to see how the replacement circuit, even such a cleverly designed compact one, is so much larger than the original IC... imagine how large, for example, the Apollo Guidance Computer would have been if ICs had not been used!
With smallest surface mount transistors available today the area taken by transistors would be smaller than the area of the chip packages. Marc used leaded packages. There are unleaded BGA packaged transistors that are ~2x2mm in size. You could replicate the entire IC in the area of the outline of its socket :)
Marc, superbly done! Now you're getting me motivated to try a repair both of mine!
The more I learn about electronics from others the more I think of it as a bit of black magic.
I so wish I had any understanding of analog electronics. But at least I learned one thing from this video: there is actually an English word "ersatz" which pretty much means the exact same thing as in German!
Very nice video, glad you were able to duplicate the function. I looked up those transistors the other day and also noticed different vendors had different speeds.
Truly impressive, congrats on fixing your hardware.
I always wondered what you did for a profession. I just assumed you were university professor but you seemed much too smart for that. Now I know!
Amazing, Marc. Very well done. Bravo!
11:12 Tektronix be like "I know you love racks so we put racks in your racks so you can rack while you rack"
I did a similar repair of an old 1973 HP 1710A oscilloscope in the mid-1990's. This to the 150 MHz vertical deflection output. This using 2 dual matching transistor sets as the original part was not available. I still use it. No new board, but routing of some leads as the new package was larger than the original. This scope has DTL logic components in it.
Very impressive Job !
And nice to see the 7854 used again
May i (again) suggest a Video about it, maybe a little explanation of programming it and the priciple of analog Sampling?
I only started using solder paste and stencils about a year ago, but I found that I get much more consistent results if I add a long blob of solder paste along the top edge of the stencil (just above the holes), then use a credit card style squeegee in one pass.
Holding the squeegee close to 45-degrees to the stencil with an even pressure, then doing just one swipe downwards.
Apparently, if you try multiple passes, or dab the paste into the holes, it can tend to push the paste under the stencil too much, and kind of squish it around the pads. I think most factories just use an automated squeegee machine, and do one or maybe two passes max.
Using solder paste is fun, though. It's not half as daunting as I thought it would be, and you generally have plenty of time to plonk the components on before the paste starts to dry out. The shelf life of the paste is usually very good, too. I bought some paste a year ago, and don't store it in a fridge, and it's still fine.
This is genuinely my first ever attempt at using solder stencil and paste, and the first ever swipe, in one pass...
i.imgur.com/ApnV23C.jpg
But I didn't have the right kind of regulators in stock, so try not to laugh. lol..
i.imgur.com/Xnza7T9.jpg
I can't agree that the UI on Eagle is anywhere close to "atrocious" btw. lol
I tried many many PCB CAD programs before Eagle, including Cadence, Protel, PADS, P-CAD, Proteus, and most others that begin with a "P".
I found Eagle to be far more intuitive to pick up than most, but I get that it's a personal taste thing as well.
I am hoping KiCAD will continue to improve though, as I definitely agree that the subscription model for software like Eagle isn't ideal.
What I can say is that they started moving the toolbar icons around from about Eagle 8 onwards, after they were in the same places for over ten YEARS. Which was incredibly annoying. I still stick to Eagle 7, mainly for that reason.
(and they removed the colour from most of the new icons, which makes them much harder to see on a quick glance. sigh)
If KiCAD can fix the problems with mousewheel zooming in Windows, and make a few other UI improvements (like making it more obvious where the button is for tying a new footprint to a symbol library), then it could end up being the de-facto PCB software.
KiCAD does seem to be a bit more reliant on learning a few keyboard shortcuts, but it's not too bad otherwise.
I found it very frustrating to use at first, but I guess it's a case of sticking with it.
For now, I'll probably continue to use Eagle, or use Altium for the most complex projects involving BGAs / FPGAs. The auto pin swapping in Altium is awesome, and the Interactive Routing tools, but I do find it's library editor confusing.
I'm interested in trying more RF stuff at some point, but it's still a lot of voodoo to me. lol
The closest I got to "RF" is using Saturn PCB Calc to work out the trace width to get closer to 50 Ohms impedance for RDRAM traces (250 MHz / 500 MHz DDR)
Wow that looks really clean! To me it shows that you really love what you are doing. Very inspiring ❤️
Very good. That old scope certainly works! I've recently transitioned to KiCad too... and it does seem to work.
Must love that old modular scope, excelent work by the way; not that I'm qualified to judge it but i like a work well done and all the things you do are done great from the electro-mechanical stuff to the RF
If you ever get problems with dead ROM Chips on the 7854, a Guy in Germany created a great replacement Board that has even the Calibration Firmware selctable by a switch.
Congratulations! Victory over HP Unobtanium!
Well done. You have microstrip not stripline.
Immaculate! Great video.
This was such a great repair and video. RF magic
I use my hot plate to do the soldering too - I've found it works very well.
i love this series! you the best!)
i discovered your channel today and subscribed immediately ... better late than never ;) wondering if i was living under a rock or something... :D
Nice to see a sucessfull repair.
An enjoyable and useful video - thanks again.
Wow this made my entire day perfect.
Egad, that scope tho. Storage scopes with CRTs warm my heart. (And my lab, if I had one, but hey)
omg i was waiting impatiently for this video
Nice Frankenstein repair ;-D
Hopefully the other output doesn't crap out as well.....
Oh Boys you are a Reference for this work!
Very fascinating. Thank you
Someone once told me that the black magic content that goes in to the pcb design increases with the square of the frequency...
It's fun when you need an x-ray machine to see what they are doing with filters and other components BETWEEN layers on a board.
@@projectartichoke I think, I once saw someone build a simple radar gun (that doppler type for speed traps) with the RF path with no components, just cleverly formed traces on the board. You can do some fun stuff if you understand Maxwell...
Definitely gonna subscribe to your channel
Nice work.
Well done, Marc.
Congrats! That was very interesting. Will you be informing us if the RF wizards have some comments on your design? As a newbie I'd say it looks very clean.
My. If they ever see that one I’ll have to hide in a corner. I fear that they are going to put it on the big screen at one of our strategic technical meetings to embarrass me, and everyone is going to roll on the floor laughing, “look he made a 2mm 50 Ohms line at 1 GHz”, mwahahahaha!” and I’ll have to pay for all the beers. These guys make 110 Gb/s go through 3 feet of cable and two 100 pin backplane connectors for breakfast. This is not real RF engineering, it’s just RUclips Electro-Monkeying-Around. That said, you can do it with amateur means, and it demonstrates the basic principles so it is very educative. At least that will be my line of defense...
CuriousMarc they have the benefits of simulations with bells and whistles though. Get them to do it with a slide ruler and a pencil, then they can laugh at you!
@@CuriousMarc I mean it works :) so there should be nothing to complain about haha
@@CuriousMarc Hi Marc. Do not be so tough with yourself...you did a good job considering that it is your first time in the RF world. I have been a microwave designer and test engineer for the last 32 years so I know what I am saying! You used only amateur tools and facilities. No fancy microwave substrate with low loss (ohmic and dielectric), no em or microwave circuit simulator...and, basically it worked at the first turn on!!!Believe me: your collegues will offer to pay 10 beers to you!!! Regards from Italy and again, bravo!!
@@CuriousMarc It is the 3 feet vs. an inch or so. Been there, done that with ECL at 600 MHz. Interestingly enough a 30 AWG wire wrap wire flat on a ground plane makes a really nice microstrip line at 50 ohm impedance. A 12" distance at 600 MHz on a breadboard - no problem.
Marc, in real time, how long did this repair take? Thanks!
Hard to say. Month and a half start to finish, but I was doing three projects in parallel, and there was lots of waiting for parts and PCB fab. Plus filming slows me down considerably. Maybe two weeks of work?
That screen shot at 20:50; any similarity to electron vacuum tube transmission between diode and cathode?
Excellent video as always. Kicad is very good and getting better. Video highlight vis 'evil omnicorp'? [1:02-1:08] "Now you need to pay to suffer"
bravo Marc
I'm very interested in this sort of thing but am only the most novice of electronics hobbyists. If anyone has a moment would you mind explaining to me what a pulser like this might be used for? Thanks!
That is definitely a more specialized piece of gear. I believe the main market for this was test and characterization of digital ICs, also radar work. My interest in it is for working with core memory, as you can see in this episode: ruclips.net/video/AwsInQLmjXc/видео.html.
@@CuriousMarc thanks so much for taking the time to respond. I've really been enjoying going through your videos.
I had been introduced to the concept of core memory in a Smarter Every Day video a while back and found it fascinating. Your video gives more insight on the subject and I greatly enjoyed it. Thanks again!
Nicely done !
Kicad for the win!
Does it really say 'Ersatz' in the opening titles?
*Happy German noises*
Had to deal with 0402 in an RF design a while ago which went better than expected with high quality tweezers for hand soldering.
One tip an RF engineer gave me: Place resistors upside down to minimize stray inductance.
"Ersatz" found it's way into English many years ago now.
Great video, thank you
Thanks Marc!
Very nice repair, stunning. Can you make a scan of the IC schematic available somewhere, please?
Yes I have a lot of work to do on the documenting. I need to revise my PCB and schematics too with the new values and the correct landing pads for the transistors before I publish it. Will be available on my website (www.curiousmarc.com) eventually.
5:21
*Mouser* _has left the chat_
I surely enjoy your videos even though I don't really understand them. I was wondering where you find all the equipment? It seems like you have a large selection of vintage HP equipment that hasn't been manufactured for many many years. Do you have grad students that help you track down all the peripherals you need to work on the equipment?
It’s mostly eBay sourced, some local auctions too. The scope was tossed from the lab at work as being hopelessly outdated and slow many years ago. It is the instrument that started the collection.
Nice repair although I would of thought an SMT cap would have been a better choice for decoupling RF. The beauty of ECL is it doesn't need much decoupling as the supply rail currents are balanced.
Marc, have you solution for the output amplifier on a HP8601A ?
Talking about high frequency design software, I recently picked up two DDS tapes on the flea market. According to the labels, one is HP 85180A HFSS software, and the other is HP 85150B & 85250A MDS & RFDS software. Both tapes are made by HP in the 90s for the HP 9000 Series 700 workstations. (believe or not, HFSS was once owned by HP!)
I've got an HP9000-712 motherboard around but don't have time to power it up. If you are interested maybe I can send the tapes to you. I'm not sure if they work or not, or there's any license required to run these software, but if they work it would be a very interesting video.
Looks like MAME has a HP9k driver, so getting them dumped and running on any modern computer might be feasible.
That era of HP9000 700 machines could use HP-HIL dongles (or flex LM license server.) So, depends on the software. Getting the right dongle is .... a pita but yes if so the protection can probably be cracked.
Could the transistors you need be salvaged from a satellite dish LNB, They have surface mount low nios GA transistors.
No you can't. The semiconductors used in LNB are HEMT which are similar to FET transistors but for microwave frequencies. The semiconductor is GaAs I.e. gallium arsenide. ECL uses BJT semiconductors. They are on silicon substrate. Regards from Italy.
How how RIGHT you are about Eagle!!! LOL!!!
But you have only 3ns pulses with this mod? You can't go for 2ns with that transistors or I am wrong? Anyway i don't think you will never use 2ns. Fascinating, I would have bet that it wouldn't work, because of the new signal path.
I only realized it was slightly slower when I put the video together. I was really shooting for the 1ns rise time. Looks like it affects only the ND pulse for some reason, which you can see has a min of 3 ns. But not the “regular” delayed pulse. Not sure how it is in the original instrument. I might swap in the faster circuit once I get the correct resistor for it.
Excellent !!!
Good job.
Well done you clever fellow
What was the highest bandwidth sampling head for the 7S12?