Tektronix 7104 for 100 eur? - Page 1
Forum section: electronics / testgear

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 30, 2016, 06:35:00 am
content: Would you get a working tektronix 7104 with 4 modules installed (dont know exactly which ones), no probes, for 100eur?Im not very fond of analog scopes, but I know this thing is a beast although Im not sure what I would use it for...

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2016, 08:29:16 am
content: I might,IFI had the space, but I'd want to be a lot more sure what I want to use it for.It probably depends on the modules too, for instance if it had a couple of sensitive differential input modules... You need to know what it's got. Post a picture if possible.

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 30, 2016, 08:32:07 am
content: Will try to post some.Actually I was thinking of getting it just for the HV supply inside (12kV and 2400V ??), could come in handy for my lab.

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2016, 08:43:47 am
content: There are easier and safer ways of getting high voltages. The ones in a scope are heavily embedded. It's +12kV and MINUS 2400V, I don't think you will get around that. The supplies will take very little abuse too, they are very specific purpose (ie. driving the tube), they will fry very easily if you short them for instance.Personally I'd turn it on, put on a decent waveform, lower the lights and enjoy!

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 30, 2016, 08:52:28 am
content: Quote from: Gyro on July 30, 2016, 08:43:47 amAgreed, but I'd better wait for wintertime to do that

author: iDevice
author_rank: Regular Contributor
timestamp: July 30, 2016, 09:53:42 am
content: 100€ is certainly good value for money.But it depends on what you would use it for.I don't now if you are aware of the "specialty" applications of this particular model.The 7104 is a 1GHz Micro Channel Plate CRT scope. It uses a special MCP tube to amplify the electron flow reaching the phosphor so that even a 1GHz signal is still visible.The drawback is that this CRT is not as bright and smaller that the standard CRT and cannot be used for more than a few minutes at a time at very dim luminosity or even seconds at normal luminosity to preserve the MCP plate which unavoidably looses a bit of life each time.Which means that most of the 7104 still living are often heavily burned by now.Besides and because of this drawback, without the proper plugin's, this model is not very interesting in comparison with other 7000 series chassis.You need 7A29, or at least 7A19 vertical plugin's and a couple of 7B15/7B10 timebases.If this is the case and you have a need for looking at 1GHz signals then yes, this boat-anchor has still a degree of usefulness.As my digital scope is limited to 500MHz, I still use my 7104 for signals beyond this BW.With a 7A29 plugin, I can still sync and see stuff beyond 2GHz (uncalibrated of course), but I wouldn't consider it for everyday use.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: July 30, 2016, 04:26:31 pm
content: Errrr, no.7104 is bright enough to burn you eyes out. They work fine as a daily user Tek 7000, which is what has been done with the three that live around here. It is one of the best of the Tek 7000 series. There are little if any trade offs when compared to the other varieties of Tek 7000. The micro channel CRT has an electrons hitting the CRT integrator that essentially watches the amount of energy whacking the CRT, once the internally set limit has been reached the E gun shuts down to protect the CRT with a red LED on. The yellow LED varies intensity to not the amount of viewing time available. Under normal scope usage conditions, viewing time is not really an issue. Tek 7104 is compatible with all Tek 7000 plug ins made.Tek's micro channel plate CRT technology was also used on the 2467 portable and 11302.Where the 7104 comes to it's own is the ability to see low duty cycle events, nano to subs nanosecond pulse events that occur over uS or mS. This is one of the reasons why th 7104 was so favored by the Physics and Optical folks. It also has a horizontal BW of 300-350Mhz allowing X-Y displays that are not possible on other CRT scopes. It remains one of my all time fave Tek 7000 main frames, remains the daily user scope.http://www.vintagetek.org/wp-content/uploads/2011/10/7104-Springer-article-email-res.pdfhttp://readingjimwilliams.blogspot.com/2011/08/scope-sunday-4.htmlBerniceQuote from: iDevice on July 30, 2016, 09:53:42 am

author: David Hess
author_rank: Super Contributor
timestamp: July 30, 2016, 05:49:35 pm
content: I would jump at the chance of getting a working or repairable 7104 for 100eur.Quote from: MasterTech on July 30, 2016, 08:32:07 amYou want one of the greatest analog oscilloscopes ever made just for its unremarkable power supply? This just shows that Europeans do not deserve such fine test equipment and I will remember your post next time someone from Europe complains that used Tektronix gear is so rare and expensive over there. Look for a junked 7603 or 7704 instead if you want a power supply.Quote from: iDevice on July 30, 2016, 09:53:42 amThe 7104 is still useful with lower bandwidth vertical plug-ins when dealing with low repetition rate signals.The very common 400 MHz and 500 MHz 7B80/7B85/7B92A timebases are almost as good as the 1 GHz 7B10/7B15. I would actually prefer the 7B80/7B85 since they support peak-to-peak automatic triggering and the 7B10/7B15 do not and I rarely use the fastest timebase settings on my 7904 or other high bandwidth oscilloscopes even when viewing transition time limited signals anyway.I thought maybe the 7104 delay line might be too short for the 7B80/7B85/7B92A timebases but the 7104 manual indicates that they work fine in it.Of course if the 7104 in question comes with unspecified plug-ins, who knows what is installed. My 7904 came with a 7D13, 7CT1N (why I bought it), and 3 other plug-ins that I have forgotten but probably included at least one 7B53A.As far as the 7104 MCP CRT operating life, I do not think it is any worse than the 7834/7934 storage CRTs. The real problem is that it is too easy to damage them through abuse.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: July 30, 2016, 09:59:43 pm
content: Please, don't fight - these Tek 7xxx series scopes do have their cult followers. So, maybe selling it on would be a great idea...or it will maybe endear itself to you after having saved it from the scrap heap.And no, I wont trade it for the Fluke. But, in fact, the Fluke might soon get children at Tamoggemon. AFAIK, you have my email adress...tell me what you need a HV supply for, and maybe we have a deal.

author: tggzzz
author_rank: Super Contributor
timestamp: July 30, 2016, 10:16:29 pm
content: Quote from: David Hess on July 30, 2016, 05:49:35 pmIn the recent UK sale, with condition unknown, arrange your own packing/shipping:Tektronix 7613 oscilloscope, 100MHz inc: 7A18, 7B53A £10Tektronix 7603 oscilloscope, 100MHz inc: 7A18 trace amps, 7B53A dual time base £11Tektronix 7704A oscilloscope, 200MHz inc: 7A26 trace amps, 7855 delay time base, 7880 time base £10Tektronix 7704 oscilloscope, 200MHz inc: 7A26 trace amps, 7885 delay time base, 7880 time base not soldTektronix 7704 oscilloscope, 200MHz inc: 7A26 trace amps, 7885 delay time base, 7880 time base £10Tektronix 7603 oscilloscope, 100MHz inc: 7A18 trace amps, 7B53AN dual time base not soldand I'm sure there were others, but I can't be bothered to find out!

author: timb
author_rank: Super Contributor
timestamp: July 30, 2016, 10:29:33 pm
content: Quote from: MasterTech on July 30, 2016, 06:54:55 pmNo, he's not saying you should hang it on the wall like a rare painting... What he's saying is that these scopes are getting rarer and rarer and the thought of someone buying one, just to gut it for the HV power supply is pretty barbaric.It's a *ONE GIGAHERTZ ANALOG SCOPE* ffs! Sure, it's not a super modern DSO, but it's still very usable for looking at high bandwidth signals.If you can't use it, resell it. I assure you there's plenty of people that will buy it, heavy or not.

author: David Hess
author_rank: Super Contributor
timestamp: July 31, 2016, 01:19:16 am
content: Quote from: tggzzz on July 30, 2016, 10:16:29 pmI was talking explicitly about a 7104. I have 7000 mainframes which cover all of the ones you listed. The 7104 is uniquely useful.UPS has a habit of destroying well packed 7000 mainframes so I am bidding my time until one shows up locally but it is pretty unlikely. Until then I have a fast storage oscilloscope and a fast DSO for low repetition rate high bandwidth signals.

author: David Hess
author_rank: Super Contributor
timestamp: July 31, 2016, 01:24:30 am
content: Quote from: MasterTech on July 30, 2016, 06:54:55 pmHaving lived in the US all my life, I would.I elected to deliberately channel Linus Torvalds to make a point.QuoteI would hope that it would get used rather than being chopped up for an unremarkable power supply.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 31, 2016, 03:23:24 pm
content: A 7000 series and a 7104 especially would be a very nice and likely useful addition to most benches but it will take up a significant amount of space and the bench needs to be very sturdy. I don't know if my experience with the 7000 series is representative but so far my experience indicates that for every 2 plugins you buy on eBay 1 will work very well and the other will either need to be at least somewhat repaired (but probably not totally) or it will become a parts donor. The good news is that eBay seems to have a steady supply. I haven't found other abundant sources of 7000 plugins - others here might know where to find them.As for the MCP, plenty of those are still operating well due in part to people who have owned them have likely appreciated their usefulness and their place in oscilloscope history, and also because of the built in circuit that times out off as needed. As noted in other posts the MCP was used in the 2467 models and the time out circuit seems to have been very thoughtfully designed. My experience with a 2467B is that for every 1 time the time out circuit is annoying I am thankful and appreciative for it about 10 times.If you know you are short on space or you don't have much use for the 7000 series or you aren't really enamoured with vintage Tektronix equipment I'd say either pass or resell it to someone would really enjoy it. (Packing a 7000 for a successful shipment will require good packing materials and skills plus a labor of love; and the cost of packing materials and shipping will likely be a good fraction of 100 Euros.)The 7104 is a classic among classics and it deserves better than being a power supply donor for some non-7000 repair project.

author: David Hess
author_rank: Super Contributor
timestamp: July 31, 2016, 06:11:46 pm
content: Quote from: Electro Fan on July 31, 2016, 03:23:24 pmThat is my experience as well; about half of the plug-ins work with a minimum of maintenance, 25% require serious work which may involve diagnostics and just replacing one part acquired from a donor plug-in, and the last 25% are only worthy of being parts donors like a 7B53A with a broken cam switch.I bought my first 7000 mainframe, a 7603, and a full set of plug-ins at the TRW ham radio swap meet in Manhattan Beach, Southern California. There were piles of mainframes and plug-ins there 20+ years ago. Swap meets with electronics located around aerospace centers (Southern California, Massachusetts, Chicago, Seattle) may still be a good source. I also see a fair amount of 7000 gear on Craigslist in those areas. The local market here around St. Louis dried up years ago after the aerospace industries moved on but I managed to pick up a 547 to go with my 545A. Now *those* are space heaters but they *still* have features (dual delayed timebase and alternate sweep) not found in inexpensive modern DSOs.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 01, 2016, 07:50:17 am
content: Hello,what can I say. The 7104 - incidentially like the super expensive TS-81000 from iwatsu - definitely are in a league of their own.The question is of one needs them. At Tamoggemon H.Q., we answered this question with no and went for a TDSxxx 1GhZ unit. But from a pure nice to have aspect, if I would get one for so cheap...

author: TerraHertz
author_rank: Super Contributor
timestamp: August 01, 2016, 12:01:33 pm
content: YES! I would (if I had 100 EUR atm.)Because I already have a 7104, which was working when I got it but due to a stupid, clumsy goof, I broke it badly during cleaning. Fumbled the EHT plug while disconnecting it, about half an hour after running the scope. The intention was to short the male plug to chassis, but instead I dropped it past the deflection board, which it arced to. Sob... all those unobtainium custom HF amp chips.Hence I have a very frustratingly dead 7104. For which I'd love a spare main power supply and deflection board.Maybe if you do strip yours, we can do a deal? Tragic though it is to scrap a 7104.

author: David Hess
author_rank: Super Contributor
timestamp: August 02, 2016, 12:10:01 am
content: Quote from: TerraHertz on August 01, 2016, 12:01:33 pm7104s with broken CRTs are available so you could get one of those and transplant your good CRT into it.

author: PartialDischarge
author_rank: Super Contributor
timestamp: August 02, 2016, 10:21:36 am
content: So here's the damn thing, I got it for 50€, and I'm already regretting it. It belonged to a woman whose husband had died. Im still not sure if everything works ok, and actually I was surprised to see that it has no BNC calibrator output, but it has the switches next to it.The CRT looks ok, pretty bright and decent, although im no expert.It has 2x 27A26 a 7B71 and a 7B10 modules. One of the modules has a sticker in german so it's probably where it came from.I'll take some time to try to see what works and what doesn't and then I'll decide if this thing lives or not.Terraherz what modules did you exactly need?

author: rsjsouza
author_rank: Super Contributor
timestamp: August 02, 2016, 10:40:41 am
content: Mastertech, the oscilloscope looks very clean and, at 50 Euros, it is truly a bargain if you have the space. I wonder how much you would get from selling it as a whole or in parts.

author: iDevice
author_rank: Regular Contributor
timestamp: August 02, 2016, 12:47:57 pm
content: Quote from: MasterTech on August 02, 2016, 10:21:36 amLooking at the state of the beast, it's a real bargain.I got mine a few years ago for the same price and had to restore it extensively.The screen looks bright because the dark filter has been removed I guess.One thing you can do to see how much the CRT is burned is to move the trace just outside of the frame and then set the trace brightness much higher until the whole surface glow.At that point, you will see the darker (burned) areas.Don't do that more than a few seconds though.If you don't see too much damage (the readout areas are usually the most visible but the most important area is around the center) then you have a winner that has a much greater value than what you paid for.QuoteExcept for the 7B10 timebase which is matching the scope BW, the others are pretty "average" for a 7000.The 7A26 are 200MHz vert. plugins which is a bit a bit disconcerting in such a mainframe, so I guess the previous owner had an assortment of plugins with at least one 7A29 or 7A19 but used these 7A26 when he needed 4 channels.In your place, I would ask the lady if she has seen other plugins laying around in her late husband shack.One thing for sure is that each of these plugins is already worth the amount you paid for the total...

author: med6753
author_rank: Super Contributor
timestamp: August 02, 2016, 12:48:22 pm
content: It's too bad you are in Europe. If you were on this side of the pond I would make you an offer and relieve you of your "regret" in about 1 ns.

author: MadTux
author_rank: Frequent Contributor
timestamp: August 02, 2016, 01:34:18 pm
content: If you don't like it, please put that 'damn thing' back on ebay or give it to a fellow over here.The sticker is most certainly from German Airforce, LW Werft 21=> Luftwaffe Werft 21.Google says that was a unit on the Airforce base in Wunstorf.Probably got decommissioned 1990 after Soviet Union broke down and someone took it home.

author: PartialDischarge
author_rank: Super Contributor
timestamp: August 02, 2016, 05:50:04 pm
content: Good news, preliminary tests show that all 4 channels and 2 triggering modules work.CRT looks ok except for a little burn at the left top corner readout. and the zero horiz line.The last image shows a 450MHz sinewave fed directly from the signal generator (I know I know...)

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 02, 2016, 09:14:16 pm
content: Hello,looks great. Definitely not worthy of scrapping...Tam (got your PM, respond soon)

author: David Hess
author_rank: Super Contributor
timestamp: August 02, 2016, 10:09:17 pm
content: Quote from: MasterTech on August 02, 2016, 10:21:36 amSwapping the timebases will required to allow delayed sweep capability; the delaying timebase (7B71) goes into slot A and the delayed timebase (7B10) goes into slot B. I would replace the 7B71 with a 7B85 to get automatic peak-to-peak triggering and delayed and delta delayed sweep capability with a time readout. I would actually consider the 7B85/7B10 or 7B15/7B80 combination better than the official 7B15/7B10 combination but in practice the difference usually will not matter.Quote from: iDevice on August 02, 2016, 12:47:57 pmOr he preferred using standard and inexpensive high impedance passive probes. I mostly use 7A26s in my 400 and 500 MHz 7000 mainframes unless I must have higher bandwidth.

author: george.b
author_rank: Frequent Contributor
timestamp: August 03, 2016, 04:04:49 am
content: Quote from: timb on July 30, 2016, 10:29:33 pmQuoted for truth.QuoteI can't imagine in which parallel universe I'd regret getting a 1GHz analog scope for 50€...Methinks you should sell it on to someone who'd properly appreciate that nice piece of equipment.

author: Electro Fan
author_rank: Super Contributor
timestamp: August 03, 2016, 07:37:10 am
content: Better sell it soon before you start to like it and then have to start buying plugins and probes

author: iDevice
author_rank: Regular Contributor
timestamp: August 03, 2016, 12:22:55 pm
content: Quote from: MasterTech on August 03, 2016, 05:15:56 amIt just moves up a bit the corresponding trace to identify it among all others.Handy when you have 4 of them.It also displays "IDENTIFY" on the corresponding readout.There are even probes with a button you can push to remotely do the identification, nice when all your hands are occupied...

author: iDevice
author_rank: Regular Contributor
timestamp: August 03, 2016, 12:34:22 pm
content: Quote from: David Hess on August 02, 2016, 10:09:17 pmYes, your right, that as well.I only use my 7104 for high BW jobs so always 50 Ohms and when you need high impedance you go FET probe anyway.I don't know, it's probably me but I never could see the 7104 as a standard daily use scope.For me it's just like using a vintage '70 Ferrari to commute everyday to the office.

author: PartialDischarge
author_rank: Super Contributor
timestamp: August 03, 2016, 12:43:40 pm
content: thanks, what about the red light "shutdown" blinking? it means that its about to turn off the beam cause im doing something wrong??

author: iDevice
author_rank: Regular Contributor
timestamp: August 03, 2016, 03:01:38 pm
content: Quote from: MasterTech on August 03, 2016, 12:43:40 pmWell, that's what I was talking about when I dared to say it is not an garden variety scope...The flashing red led tells you that the MCP protection will kick in in a few seconds unless you seriously reduce brightness.So you have to keep brightness of A & B traces quite low, as well as the readouts, to avoid this kicking after a while.Sure, this scope can give you quite a bright spot when you need it but only for a few minutes.This is the reason, I don't understand how this can be used as an everyday scope, unless your lab is a darkroom...Waiting for the fanboys reaction now.

author: siggi
author_rank: Regular Contributor
timestamp: August 03, 2016, 03:22:36 pm
content: Quote from: iDevice on August 03, 2016, 03:01:38 pmWhat, wait, your lab is not a darkroom? You can do that? It's allowed, even?My 2467 with its MCP CRT is my daily driver for general spelunking. I have to say the CRT-saver is seldom a nuisance. Given any high-repetition signal, it just isn't necessary to crank up the intensity to the point where it gets antsy.However, it now has competition from a HP 54622D, which - while being a digital scope - boots faster and is almost as responsive and intuitive to drive as the analog Tek.

author: David Hess
author_rank: Super Contributor
timestamp: August 03, 2016, 05:39:13 pm
content: Quote from: iDevice on August 03, 2016, 12:34:22 pmIt is not just the high bandwidth which makes the 7104 special though; the MCP CRT is also good for low repetition rate signals and if care is used, life expectancy is not a worry. Siggi (hey guy, I have not seen you post for 2 or 3 weeks on The List) mentions using his 2467 which also has an MCP CRT as his daily oscilloscope.After I got my 500 MHz 7904, it replaced my 100 MHz 7603 for general use not because of its higher bandwidth since I prefer the 200 MHz 7A26 vertical amplifiers for the same reason the previous 7104 owner probably did but because the 24kV CRT is so much brighter and sharper than the larger 15kV CRT in the 7603. A 150 MHz 7704 or 200/250 MHz 7704A would have the same advantage since they have the same 24kV acceleration voltage but the 7904 is what I have and I am not complaining. Admittedly I would probably use any of these 24kV oscilloscopes if I had them in place of a 7104 until I needed its special capabilities.And about the special capabilities of the 7104, how many devices allow one to experienceapparent motion faster than the speed of light? And as a single shot event visible under room lighting no less?

author: Rupunzell
author_rank: Frequent Contributor
timestamp: August 05, 2016, 06:58:59 am
content: Two of Jim Williams fave O'scopes. Tek 547 & Tek 7104.What a proper work scope cart should look like:One needs to spend a decade or more driving a Tek 547 doing analog design, then an appreciation of just how good the 547 is for analog stuff can be. The CRT trace quality and definition has yet to be replicated in a production crt O'scopeJW memorial published this June 2016 EDN.http://www.edn.com/design/analog/4442194/4/Remembering-Jim-Williams--5-years-laterAfter a while of observation and reading it appears analog O'scopes are much like cars of years gone by with manual gear shift, no power steering, no power brakes, no ABS, no traction control, no driver assist. The driver had to do most if not all the driving. If this is a performance car, it would mean essentially driver wears the car rather than driver being coddled by the car with numerous techno driving aids. In the case of the Tek 7104 in the world of Formula One race cars it would be much like this McLaren MP4/4 Senna once drove (now being driven by Lewis Hamilton).The modern DSO in many ways is similar in concept to the modern F1 car with many technology based driver aids, energy recovery, finely balanced aero and much more... Better, maybe the are very different expression of technology intended to achieve different goals.Bernice

author: TerraHertz
author_rank: Super Contributor
timestamp: August 05, 2016, 01:23:01 pm
content: Quote from: MasterTech on August 02, 2016, 10:21:36 amIt's very kind of you to offer, but firstly I'm in Australia and quite broke atm, so the shipping probably would be a a problem.But mostly, I just couldn't bear to be the cause of that nice scope being broken up for parts.Really, if you hate it so much, list it on ebay once you've checked it's working. You should get a lot more than 50 EUR.Also I second the idea to ask the widow about any other modules lying around. Maybe go there and look yourself, as she might not recognize them. Surely there will be more appropriate ones, unless her husband didn't know what he was doing when he swi... acquired it from that base.Speaking of inappropriate modules, here's my dead 7104 frame. The modules are just parked in it for storage, not even pushed in. But someone may get a laugh from the contrast.If you actually do decide to part it out (for some reason) PM to remind me and I'll work it out.

author: MadTux
author_rank: Frequent Contributor
timestamp: August 05, 2016, 02:36:35 pm
content: Quote from: Rupunzell on August 05, 2016, 06:58:59 amI havealmostthe same stack in use at home:

author: rsjsouza
author_rank: Super Contributor
timestamp: August 10, 2016, 09:55:20 pm
content: Quote from: MasterTech on August 10, 2016, 06:38:19 pmUh-oh... That's how these things get in our lives... Taking space little by little...Nicely done! Enjoy your new scope!

author: Electro Fan
author_rank: Super Contributor
timestamp: August 11, 2016, 02:08:52 pm
content: Quote from: MasterTech on August 10, 2016, 06:38:19 pmNow we're talkin' - the 7104 and Lab 1.0 look good and your Lab / Workshop 2.0 will probably be even more beautiful - CongratsPS, after looking at your photo it would seem that you were destined to add the 7104 to you lab - it is a natural for a guy who appreciates classics like vintage radio, a HP 3580A, a Rigol 2072, Apple, and Solgar supplements

author: Electro Fan
author_rank: Super Contributor
timestamp: August 12, 2016, 05:35:13 am
content: Quote from: MasterTech on August 11, 2016, 04:40:01 pmThat is a nice mouse pad.... as mouse pads goDon't see a lot of mouse pads around these days but when it comes to not quite vintage but old school they are right in the mixAnd bakelite outside and inside - that's very likely a vintage connoisseur's delight. Don't forget to tell us the radio story.... Congrats again on the 7104! (Wait til you see that you can observe signals in the picosecond realm.)

author: JPortici
author_rank: Super Contributor
timestamp: August 12, 2016, 05:52:12 am
content: Quote from: Electro Fan on August 12, 2016, 05:35:13 amhe'll try to break the scope risetime(hint to the show us your square wave thread)https://www.eevblog.com/forum/testgear/show-us-your-square-wave/msg587792/#msg587792the madness starts at reply #5