Author Topic: Tektronix 2215 Scope repair  (Read 28930 times)

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Offline Pete F

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Re: Tektronix 2215 Scope repair
« Reply #50 on: July 06, 2018, 05:02:58 am »
Well, my gloat was short lived! The unit failed again :( I just turned it on to look at something quickly, and saw it fail.

I came into this thread having mentioned my failed 2215 in the Test Instruments section, where I was looking for a modern DSO to replace this. As I said there I was a bit reluctant to start spending too much time with this, as it was at the end of its design life. What tends to happen is that the reliability goes down, sometimes to the point where it can become a project in itself. While I’m no longer a professional in this field, I still approach it as if I was, and it’s not a hobby for me. I have a lot of things to do and this is just a tool.

Having said that, it seems it’s not worth just throwing it away, and having gone this far I may as well look at the second fault and see if I can find it. I won’t get a chance to look at it until next week but it sounded as if the PWM was oscillating but the transformer was very noisy and the power supply apparently not making voltage. The fact the transformer was noisy means the MOSFET is ok, but it could be something in the reg section. The first thing I’ll try is to replace the original caps (esp the 100 um) cap, as it’s possible that has failed in its early life. The brand was some rubbish I’d never heard of, so it would not surprise me if that was sketchy. If that’s not it, I’ll need to diagnose the issue without wasting too much more time on it. I hate it when tools start giving issues!
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #51 on: July 06, 2018, 02:42:51 pm »
Oh no, don't throw it away !  :scared:  Just send it to me, rather !  ;D  Too bad.. .shipping cost make is uneconomical.
Would be a tragedy when 99% of it's parts are still good and could help other people fix there scope ! At least you could sell it for parts on Ebay, it would make someone happy for sure ! 

But I think yo might better off keeping it : as you said your scope is a tool not a hobby. So having a backup scope (once you do get a DSO) will avoid any downtime when/should the DSO fail.  The peace of mind of having a backup scope is well worth the few bucks and a few ours fixing it !  :)

So, it fell apart again... meaning maybe it's time to dig further and do as I suggested earlier. Pull the regulator board and power the scope/inverter directly from a lab power supply, 43V and current limited to no more than 1Amp, and let it run for a while.

This way you will immediately see where the root cause of the problem lies : pre-reg board, or downstream (inverter of secondary side of the scope).
I think trying to bypass this (very quick and easy) step will just make you waste more time than necessary.

Divide and conquer. Take the regulator board out of the equation to simplify and speed the troubleshooting !


Also, look what I just read on TekScope !  Someone posted this old service bulletin that Tek issued about the 2215 !

http://www.hakanh.com/dl/docs/hardtofind/SUP3010.pdf

They admit that they did a big mistake that causes the CRT to die/wear out very prematurely, causing a dim trace at fast sweep speeds, in a very short amount of time ! They notified all US customers about it, with a free CRT replacement for any scope brought to their service centers, no less. Howevr for non-US customers, no steps where taken to ensure that all scopes where fixed.

Just checked mine, yep, its serial number is smack in the middle of the affected range, and nope, it has NOT bee modified/fixed ! ARRRRRRGH ! Too late now, nothing will bring the filament from the dead.
I have not paid particular attention to the trace brightness at full sweep speed, but when I do and I find it's way too dim... at least I know that it's not worth waiting time troubleshooting something that just can't be fixed !  :--

This obviously once again illustrates Floobydust's plentyful experience of these scopes back in the day : "immature, rushed to market...."

Yeah, there is decidedly something going on with these 2215... definitely one I will not buy again... you live and learn ! ;D

Still, at least it's a great scope to get some repair experience, because repairs it needs plenty of ! LOL

 
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Offline Pete F

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Re: Tektronix 2215 Scope repair
« Reply #52 on: July 06, 2018, 04:40:06 pm »
Yes I’m fairly sure the issue is restricted to that board, so no need to isolate it. It’s quite likely there are other latent faults with the unit, but that can lie there :) I’ll know more next week when I have an opportunity to look more closely at it.
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #53 on: July 14, 2018, 10:10:07 pm »
Hmmmm... just happened to watch the latest video from the repair blog " Artifact Electronics ", he is currently working on an old " TRS-80 " 8 bit computer, is fixing many issues with it, and oh, at 7 minutes and 40 seconds, starts an interesting bit !

https://youtu.be/lmMi0KvUebw?t=460

Yep... despite this machine having nothing to do with an old 22XX Tek scope... this old computer has also an SMPS doing the same horrible high-pitch noise.... and the most interesting bit : as far as I understand, looks like the culprit was... a leaky/bad electrolytic cap on the secondary side of the power supply. He replaced just the one, and the noise went away !

So... looks like the recap I just did on my 2215 SMPS might indeed be responsible for fixing this horrible noise ! So definitely well motivated to recap the SMPS on my noisy 2232, no question about it !  I can't believe that there was so much discussion about this noise in these old Tek scopes, theories of transformers, FETs, resonance, and what not... when probably in many cases at least, all that was wrong was, again, the dreaded crappy old electrolytic caps ?!  :palm:

It's now so cheap to get top quality caps on-line, of any value and voltage rating you want... I am starting to think that some people are right... just recap the SMPS no matter what. Can only make things better, and in any case will be good preventative maintenance because they would cause issues later down the line any way, sooner or later.  I think it was David Hess last summer who was suggesting me to recap the SMPS of my 2232 from the get go. Will do soon, and if that fixes this horrible high-pitch noise... will apologize to him for not listening !  LOL   Admittedly back then, I had enough problems with that scope, and was so inexperienced that my plate was full enough... adding a recap to the list was a bit too much for me back then. Not any more !  :box:

Okay... have not worked at all on the 2215 lately, busy with work and things. Not been inactive though : spent quite some time studying the schematics and reading up some of the "Theory of Operation" sections in the manual. I am not so much in the dark any more as to the weird symptoms I am seeing. Just need some time to get to the workbench and fiddle with the scope. but I am hopeful, it may not be as lost a case as I thought... crossing fingers ! ;D

Sorry for being vague, will be much more concrete once I have managed to actually work on the scope and report !  ;D

« Last Edit: July 14, 2018, 10:14:15 pm by Vince »
 

Online tautech

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Re: Tektronix 2215 Scope repair
« Reply #54 on: July 14, 2018, 11:06:16 pm »
 :)
Yes, it's not until you start playing with boost/buck magnetics that you fully comprehend how sensitive they can be to component variations.
As I'm sure you'll find with your 2232 jsut an out of spec cap can force them into an unhappy mode of operation.
Some of the e-cap changes can be quite subtle or just the additional current load of slightly leaky remote bulk caps somewhere else in an instrument.

I used to think just reasonable accuracy capacitance measurements were enough to find the culprits and generally it is, but not 100%. Sometimes cap leakage is voltage dependent and there's been great discussion in the forum lately stemming from a LV cap tester from Mr Carlsons lab which of course might be OK for the bulk of testing we do but by no means all scenarios. Joe Smith also did some good testing of HV cap leakage by sweeping cap voltages to listed max and measuring leakage right through the working range. Pretty simple really and then compare against datasheet spec.
However, a competent 'repairman/technician' shouldn't by default be taking a shotgun approach and have some sort of ESR testing means to properly understand cap failure and know just by looking whether caps should be low ESR or not.

Many years back knowing what place SMD would play in our futures I splashed out on the best pair of SMD Smart Tweezers I could afford (and other purchases were put on hold) and they've rewarded me with reliable ESR measurements that have allowed me to identify many dud caps that don't show any signs of degradation.
The $$ hurt at the time but now knowing just how capable they are I would replace them in an instant !
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Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #55 on: July 15, 2018, 12:02:36 pm »
Hi Tautech,


Yes, ESR meter and HV leakage testers are on my list ! ESR short term, HV leakage mid-term... especially as I would like to design/build my own as it seems quite simple, so would be a good excuse to design something, and small enough a project that it would probably actually get completed, ahem...

ESR wise, my budget is limited so I was thinking of this 100 bucks DER 5000 hand-held LCR meter. For the price, I think its by far the best bang for the buck I can get, feature and engineering quality wise, and of course it would do much more than just ESR. With its 4 wire design/construction, it will be able to measure tiny pF range caps much more accurately than DMM's, as well as accurate low ohms measurements which I also need/want to be able to do.   Still, 100 bucks is still a little steep right now, and so to get me going very quickly I am now on the verge of buying one of these popular 10/20 bucks little kit ATmega based  "do it all" component testers, as they also do ESR and do a decent job at it apparently. Will also help me sort the gazillion of components I have recently salvaged, after "processing" 5 large boxes of boards.

Been meaning to buy this little tester for some time now...but somehow always finding good excuses not to... but I think I need to get my priorities straight, or else I will never get it : In the past few weeks I have felt weak and eventually spent some money for yet some more old instruments which in all honesty I did not really need... like this 2215 to start with, which cost me 60 Euros shipped. So if I don't get my priorities right, I will just pile up old gear yet not even have the basic test instruments I need. I need to balance things ! I can't justify spending money on old gear yet pretend I don't even have just 20 bucks for that little component tester.... isn't it.

Would need to make sure it can test ESR in-circuit though, or else it won't be much use. Still, I would still get one I think, to help me test/sort all my components.  As far as I understand, an ESR meter basically is just an AC ohm-meter with a signal amplitude of a hundred mV or so, low enough to make sure it won't turn on/be "contaminated" by PN junctions, even old low drop 0.25V germanium diodes.  Then it's up to you to implement / design it the way you like...



HV leakage tester wise
... yes I definitely intend on getting one, especially as I am getting more and more fond of these old glowing Tek scopes, and even other tube based test gear ! Recently  in the local ads I fell in love with an old Metrix 620 "LCR meter" / impedance bridge ! With its magic eye tube, and big black Bakelite knobs and lovely, thick engraved stainless steel dials that just ooze style and quality... I just couldn't resist, at only 35 Euros (and a seller willing to ship, for a change !), when this instrument usually sells for 150 Euros or more... I had to have it !   ^-^

I know... when I bought my Tek 317 scope I promised myself it would be my first and last piece of tube equipment... and that therefore, for example, I would not invest in a tube tester. That was a year ago.... a year later, I am so in love with that old Tek scope, such a joy to look at and operate, both inside and out... I feel an addiction growing fast ! I now can't help but look at every glowing Tek ad I spot in the "local"/French ads ! " Luckily " so far, they have all been way too far away from me (usually at the other end of the country...) to make it worth the trip, both from a financial point of view (gas is horribly expensive over here, any trip over 50kms starts getting costly...), as well as from a practical point of view (my right leg hurts badly after only 45 minutes of driving, and I must stop).
But.... the other day I found a 535A scope for only 50 Euros and for once, it was not too far... though not really next door either : 200kms. So I e-mailed the guy to see if he might have the opportunity to drive part of the way for some personal or business trip he may have planned in the near future... but no answer as of now. Been a couple weeks.... So looks like even this one, will escape me ! LOL

No really it's a pain. The old 500 Tek scopes do pop up regularly over here, maybe one every couple of weeks of so, country-wide, but they are never close enough to me, and of course the sellers refuse to ship them ! Mostly because well... even if they bothered packing it, the resulting parcel would exceed the weight limit and overall dimensions that the mainstream/affordable transporters  allow : 30kg max, and only 150cm for the sum of the 3 dimensions. So a 50cm cube for example... now try fitting a 500 scope, and all required packing material, into such a tiny footprint....

At least the Metrix 620 was small and light enough that shipping could be reasonably considered....

Anyway, digressing again sorry.. you know me ! :-[

So yes, a HV leakage tester is definitely on my list. It's not as urgent as an ESR meter though, and I am not aware of new/off the shelf testers (though I didn't really search that hard to be honest ...). I would love one of these period/vintage testers, but hard to come by, too expensive, and very bulky...
Given that the operating principle is simple, from what I understand (just apply desired voltage and measure/display the current using whatever form of display you like... magic eye tube, galvanometer, whatever...)... I would love to design my own...   Currents involved are very low anyway, so shouldn't be too difficult to design a suitable HV supply... should be fairly easy and not take too much space at all. Should be able to all fit in a more compact/"bench friendly" enclosure than the old tube based testers... I would think. So this little project quite appeals to me...



As for Paul's LV leakage tester.... it kinda leaves me confused to say the least !  :-\
I love this guy, been subscribed to his channel for a while now, been watching every single video in his catalog. I like the design/engineering bias of his videos, and from what I understand he is an actual design engineer, so I give him credit and enjoy all the advice and tips he gives in his videos..... however, when he presented his tester the other day, I was at a loss : HOW can you test the behavior of a component, cap or anything else, at say 600V.... unless you actually SUBJECT it to that voltage ?!  :o

From what I understand, it kinda "works" in practice, because he mostly tests 60 year old caps, so have had enough time to degrade so much that they would leak a measurable current even at only 2 or 5% of their operating voltage (especially since, AIUI, his device can measure/detect extremely low currents)... so by extrapolation, reasonable extrapolation, but extrapolation only none the less, we can safely assume that if it leaks at say 5V... you bloody can bet it will leak like mad when subjected to its multi-hundred volts operating voltage. OK, I am fine with that...

But if the cap is not that old, is only at the beginning of its deteriorating process, and only starts to leak at say 90 or 95% of its operating voltage.... several hundreds volts then.... the LV tester will not register any significant current and declare the cap good, when it is not...

So I think this LV meter is great as an INDICATOR, to help find very/blatantly faulty caps, and would be plenty good enough in practice, when working on really old caps/instruments, and I understand Paul did a lot of testing to confirm this.... but still, it's only an indicator, not an actual / reliable test of how the cap performs at its actual operating HV...

Also... the only reason Paul designed a LV leakage tester, from what I recall,  is that he thought people might get zapped when using old/vintage HV testers, by accidentally touching the test leads/jacks, or forgetting to discharge the cap before handling it after performing the test. Well... I mean, if you can't even watch your fingers and think, when you are merely testing a cap on your bench... how will you survive the process of restoring/fixing the tube piece of gear that you are trying to fix, given it has HV absolutely all over the place, if you can't even watch where you put your fingers and pay attention to your own safety ?!

Hell, how can you fix ANY mains powered piece of gear, even modern stuff... given that most of them have a 240V SMPS hence with 340Vdc or so, across the main filter cap ?!

I understand Paul is from the US where every video over there, starts with "do it at your own risk, I can't be held responsible for your electrocution blah blah blah", but come on... if you work on HV equipment, well... you should not do it unless you know what you are doing ! You are not some kid that needs safe guards and babying, you are an adult who knowingly chose to work on HV stuff !

Of course I am not saying we should play with fire needlessly, so I am all for making HV testers as safe as they possibly can be, by minimizing exposure to HV as much as possible, through careful mechanical and electrical design, just like a good DMM does... but at the end of the day, if you want to test a cap at its HV operating voltage, well one way or another you will have to produce said HV and deal with it !

What next ? An insulation tester that will test motor winding insulation at 10V instead of 1,500 Volts ?!...

And what should we do about all these glowing Tek scopes ? Should there be a law that forbids selling them to "unauthorized" individuals  ? I mean, ANY of these scopes have HV not just inside of course, but EXPOSED ON THE FRONT PANEL as well !!!! I mean, the probe calibrator output can be adjusted at the flick of a knob to produce no less than 100V, for starters  !!   Then,  among the few 4mm binding posts that populate the right edge of these scopes, you will find the sawtooth output from the sweep section, which ramps up to 175V  or so !!!  And this binding post is literally at your finger tips when you operate the sweep knob !  So people could get zapped easily just by OPERATING the scope, not even by opening it to mess inside of it !

Let's be reasonable...

Again, I love Paul's blog and every bit of design/engineering comments he brings to his videos.. but in the particular case of this LV tester, I really don't understand...

A great little tool, a help, an indicator, good for most practical restoration purposes of old gear, I don't doubt it, he tested it extensively and has massive experience restoring Vintage gear and dealing with these old caps.... but an actual, indisputable test instrument... it's too much of a stretch in my view  ???


Hell instead of babbling here I guess I rather ought to work on the scope !   ;D

« Last Edit: July 15, 2018, 06:57:55 pm by Vince »
 

Online tautech

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Re: Tektronix 2215 Scope repair
« Reply #56 on: July 15, 2018, 08:38:42 pm »
Vince, you have a good understanding of what's required and enough experience to help you interpret test results.
I know a couple ppl with the $20 tester and for starters it's a good tool and good value. For me, well they came out after I got SMD Smart Tweezers that measure into many K's of uF and down into pF all with ESR so I've never been temped to get one for cap testing. Active components and identification, well yes the $20 tester can do that too so some added value there. The UK Peak products interest me too and I will probably get one of their active component testers before anything else....if I need one.

Member Defpom is looking at building an HV cap tester kit and I've been watching his progress on YT but he's got some way to go with it just yet. His will go to 500V so could well be interesting once he polishes it to where it's available as a kit.
He's also got a DER5000 that we see him use in videos but I haven't seen it be any more useful than my SMD tweezers.

Anyways, it will be a sad day when we don't all yearn for more and better toys !  :-DD
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Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #57 on: July 15, 2018, 09:50:22 pm »
Thanks for the tip on Defpom's project, will check it out...

SMD tweezers yeah they look cool, but I think good ones still cost a fair bit, and for practical as tehy are, they can never compete with with a decent hand-held like the DER 5000 or whatever similar, if just because of lack of real estate to fit hardware in them, as well as buttons and a decent size display on them.

Ideally I would want both SMD tweezers, because quite practical as you said, and sufficient for many purposes.. but also a DER 5000.  But a  decent SMD tweezers would cost at least as much as the DER, if not twice as much. So I can't justify tweezers  :(
There is hope though : from what I recall, the DER can be found either standalone, "naked", or in a little carry case with some accessories... which include tweezers you can plug into the DER !  8)   I think I will probably follow this path...

« Last Edit: July 15, 2018, 10:21:31 pm by Vince »
 

Online tautech

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Re: Tektronix 2215 Scope repair
« Reply #58 on: July 15, 2018, 10:43:59 pm »
Thanks for the tip on Defpom's project, will check it out...

SMD tweezers yeah they look cool, but I think good ones still cost a fair bit, and for practical as tehy are, they can never compete with with a decent hand-held like the DER 5000 or whatever similar, if just because of lack of real estate to fit hardware in them, as well as buttons and a decent size display on them.
:)
You'll never know (and I didn't) until you own a set !
Only when the leads of a component are more that 25mm apart do you have trouble connecting to them but you can extend the leads...... SMD tweezers, well I use them more than a DMM or scope as they make finding faulty passives much much faster. On a small PCB I can whizz over all passives in less than half the time of a DMM and without need to change ranges for all passives. Capacitance and ESR measurements on the fly and for diodes, it's much faster too and gives indication of the cathode side with a single contact......no swapping probes.  :)
I use them for everything, SMD in tiny tiny sizes and TH to as big as I can comfortably spread the legs.
Mine are old ST-3 but if/when I replace them I will get the TOL set ST5S.
http://www.smarttweezers.com/st5s/

Yes, they cost as much as a new DSO  :scared: ......but I use them more than I ever thought possible when I first got them.



And I forgot.... L measurements too !  :-+

« Last Edit: July 15, 2018, 10:51:35 pm by tautech »
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Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #59 on: July 15, 2018, 11:10:25 pm »
Sounds good but just not in my price range ! :-//  And this tiny, minucule display... would need new improved bionic eyeballs  :-[

But if I could afford it yeah, why not....

Might get cheap ones just to see if I can get used to handling such an instrument, and watching such a tiny display... but not any time soon that's for sure...
 

Offline james_s

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Re: Tektronix 2215 Scope repair
« Reply #60 on: July 18, 2018, 12:44:38 am »
I really like those Tek scopes of that era. I remember lusting over them in catalogs when I was a kid, but they were way beyond what I could afford at the time. Instead I found a Tek 532A at a garage sale eventually, that was very exciting, and it doubled as a heater for my bedroom.
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #61 on: July 19, 2018, 08:54:05 pm »
Yeah they are good heaters indeed !   :-DD   Hopefully I will have finished putting mine back together by this winter so I can play with it while heating the lab at the same time  :-DD

I found these scopes so gorgeous, such masterpieces, that I am truly amazed that one can get get them for so cheap ! It's so rare theses days to find good stuff that's cheap ! So I can't resist them... I feel weak every time I see one for sale  !  :-//

There is so much old ugly crappy instruments on Ebay that sell for fortunes, that I can't understand how these beautiful glowing Tek scopes have managed to escape the speculators !  This may not last for long though, who knows... so that's another reason why I try to get those which happen to be at my reach : I try to get them WHILE I CAN ! Maybe one day the market will decide suddenly that they are "fashionable" and prices will start becoming silly, and I won't be able to afford them any more.

So I am glad I have managed to get at least one example, thanks to my little modest 317 model. Needless to say I will treat it well and cherish it...
If I can get a couple more of these scopes, that would be cool, but I have at least one so I am "safe"... I now own a little piece of history, nobody can take it away from me.....  :)
 

Online tautech

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Re: Tektronix 2215 Scope repair
« Reply #62 on: July 19, 2018, 08:59:12 pm »
If you lust after early Teks, check out threads by Martin.M.
This was his first post:
https://www.eevblog.com/forum/testgear/vintage-tek-restoration-pictures-by-martin/msg589744/#msg589744
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Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #63 on: July 19, 2018, 09:12:58 pm »
Yeah you steered me to his topic a year ago when I bought my 317 last summer, took me some time to read it all, but was worth it  :)
 

Offline james_s

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Re: Tektronix 2215 Scope repair
« Reply #64 on: July 19, 2018, 10:56:47 pm »
I found these scopes so gorgeous, such masterpieces, that I am truly amazed that one can get get them for so cheap ! It's so rare theses days to find good stuff that's cheap ! So I can't resist them... I feel weak every time I see one for sale  !  :-//

I finally gave mine away a year or two ago simply because it was so big and bulky and it was only a 10-15MHz scope. When I have a 1GHz Tek DSO on my bench and a 100MHz "portable" Tek 340 it's hard to justify keeping a gigantic antique around even though it is totally cool. My space is limited and I have test equipment primarily to use. My bench isn't a museum.
 

Offline Pete F

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Re: Tektronix 2215 Scope repair
« Reply #65 on: July 20, 2018, 05:39:16 am »
In fairness James, I feel the analogue oscilloscopes still have their place. I left the industry well before anything like the modern DSOs were available and have just been exposed to them for the first time. Obviously I appreciate some brands will be easier to use than others, but so far my experience with the DSO I have is it’s nowhere near as fast to use for fault finding and general signal tracing as my old 2215 or similar. There’s no doubting the power of the modern DSOs, even ones costing just a few hundred dollars, but it seems to me that power comes with certain trade offs.

My 2215 requires a new high voltage module, and I’ll certainly be fitting one when one comes up at a realistic price. In my opinion the two seem to compliment each other. I’m not sure I would be wanting to go too much earlier than the 2213/2215 era etc though. They seem basic enough to be realistically repairable, and the general service information is excellent by modern standards. They are from an era where we repaired things rather than adding to landfill ;)
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #66 on: July 20, 2018, 02:56:32 pm »
Quote from: james_s
I finally gave mine away a year or two ago simply because it was so big and bulky and it was only a 10-15MHz scope. When I have a 1GHz Tek DSO on my bench and a 100MHz "portable" Tek 340 it's hard to justify keeping a gigantic antique around even though it is totally cool. My space is limited and I have test equipment primarily to use. My bench isn't a museum.

Ah well yes of course, if you run a business and every single penny and cubic feet must be justified by how much money it will get you in return.. then yes a glowing Tek is not a good idea....

But I am a hobbyist, the only justification I require o buy stuff is... that I like the instrument and can afford it and I have space for it. Makes things simpler indeed !  ;D

Still, these old Teks still, in all objectivity, are still better than some brand new digital scopes ! Glowings Teks sell usually between "free, just come and pick it up", to 50 bucks.   For 50 bucks you don't have that much of brand new DSO, not even the crappiest,most bottom of the line of the most obscure Chinese brand, say Owon or whatever. In the 50 bucks range all you can get is one of those kit DSO whic are just a tiny palm sized PCB wit ha couple push buttons and a tiny stamp size LCD, with 100kHz of B/W... you see the kind :

https://www.ebay.fr/itm/DSO138-2-4-TFT-Digital-Oscilloscope-Acrylic-Case-DIY-Kit-SMD-Soldered-New-R2C0E/223067764502?hash=item33efdff716:g:LxoAAOSwaLJbTHH2

Or this one, closer to 50 Euros.. you do get a crappy plastic case with this one, and even a BNC connector for the input, woohoo luxury !  ;D

https://www.ebay.fr/itm/JYE-Tech-Dso-COQUE-Digital-Oscilloscope-Kit-15001-200KHz-DSO150-Flux-Atelier/123259803899?hash=item1cb2db58fb:g:8DkAAOSwWupa-q9-


In all objectivity, even my 1959 Vintage Tek 317, o orders of magnitude better than these DSO... even though they are 60 year younger, literally.
And my 317, even back then was hardly the best performing scope that Tek had on sale... it was just a modest field/service scope...

Still, at least :

- it has a proper case and use interface that's actually usable and even pleasing to use, and look at as well. Form and function, why choose when you can have both  ;D
It's

- Bandwidth, at 10MHz, is literally a couple orders of magnitude higher.

- Screen/viewable area is much larger, even though it's got a tiny 3 inch tube, not even the large 5" tube of the more common  glowing Teks

- Proper H/W trigger

- Wide input dynamic range

- Proper attenuator / pre-map front-end section

- probe calibrator

- has a built-in power supply, just plug it to the wall.

- can be operated with one hand, it's rock stable.

Then if you compare it to top of the line 500 scope, the advantages just get better, with a large 5" tube, often with a delayed time base, and 100MHz B/W, and plug-ins to do this and that for specialized work.

It's incredible to think that even current Tek (or other major brand) entry level scopes, 60 years later, still don't offer 100MHz B/W as standard, making them effectively less capable than some of these old glowing Teks.  It's mind boggling when you think about it......

Anyway, I am fortunate enough, being a hobbyist, to be able to buy old stuff just because I like it, no need to justify it. No need to choose between old or new, why not get both if that makes me happy...  :)

Most people around me, smoke. A quick calculus indicates that even a "normal"/average smoker, spends something like 5,000 Euros, that's in the order of 6,000 US dollars, to buy his cigarettes, an astronomical amount of money, scary.

I don't smoke, so for 5 grand a year, each and every year (given than most smokers never quit) I could buy a tremendous number of old test gear... and spend some of the money to build a larger lab to host all these instruments.

Even discarding "vintage" scopes, I would still keep both my analog scopes and DSO. They complement each other and the DSO will never be able to match an analog for ease of use and trace quality and "charm", dare I say...   I don't want to choose between analog and digital, and I don't have to, so I will keep using and enjoying both...


 

Offline james_s

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Re: Tektronix 2215 Scope repair
« Reply #67 on: July 20, 2018, 04:58:33 pm »
I'm a hobbyist, but space is still at a premium. I only have so many rooms in my house and at this point all available space is pretty well used up. Getting something new means getting rid of something I already have, so I couldn't justify keeping a gigantic old scope around when I have other scopes, including a Tek 465B for times that analog is better. I'm glad some people like the old tube scopes well enough to keep them around though, the 532 is a work of art.
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #68 on: July 20, 2018, 05:54:43 pm »
Yeah I understand, space is everything...  I only have two rooms, so the spare one is for the lab. A small 3x4meters room.

That's why I fell in love with this 317 scope. Back then I only knew about the super big 500 series scopes, just like you I couldn't see myself keeping a huge instrument like this in my tiny lab. Then I came across this little 317 model in the local ads. Looked just as nice/cool/charming as any of the 500 series scopes, but was much smaller/manageable, an ideal compromise, and such a cute little thing !  :D  Couldn't resist, bought it....

When the construction of my house will be completed, I will have a lot more room to devote to my hobby, so that's why I am now considering getting a couple 500 scopes as well, depending on opportunity.

 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #69 on: July 28, 2018, 12:34:33 am »
Well.... this is the end !  :-//

Tonight, felt like I had finally an ounce of motivation to work on the scope.... I tried to remove the alternate sweep board from the main board, so I could access it and redo most of the solder joints as it seems that not only the scope was rushed to market, but also the wave soldering machine Tek bought... or maybe the guy who set up the machine was not paid enough, or was drunk, I don't know....

Anyway,  this daughter board is no fun : vertically mounted, a single row of 27 pins, soldered directly to the main board, and all pads are double-sided.... I did my best. Wasted half the scope worth, in flux and solder wick. Underside was easy of course, but the access on the top side is not that great. Would not come off.
Eventually fired up my crappy hot air station... board was out in no time, should have used it from the get go. But was too late : I guess I heated and wiggled the board too much, and for too long, when I first tried with the wick. So the board came out, but so did 9 plated vias with it ! Ohhhhh.... nooooooo...  :-\

That's way beyond "economical repair", so I quit.

Did fire up the scope without the board though, just to see what would happen !  I was not disappointed : Tek did things right, and without this board, the scope works just fine, everything is normal... just that nothing happens when you try to enable the delayed time base... of course !

If anything, pulling this board helped in my diagnosis : one of the biggest issues was that the signal trace would disappear for any and all sweep speed below 0.5ms / DIV.   Hint : the manual says that the auto-intensity feature actually kicks in ONLY for sweep speeds from 0.5ms and up ! What a coincidence ! LOL
So I figured maybe the signal trace is there, but the intensity is somehow turned all the way down by some odd mechanism/bug.... so I made the lab completely dark and yeah, I could see the trace ! And it was behaving normally, whatever the sweep speed.... just that I couldn't see it under normal lighting conditions !

Well, removing the alternate sweep board somehow cured the problem ! I can now see the trace just fine at speeds below 0.5ms/DIV. It is still a bit dimmer than at higher sweep speeds, so there is still something that would need investigating... but the trace is now perfectly visible. Scope is actually usable now...

So I think I will keep it any way... even without the delayed sweep, it's still a perfectly good scope. Hell there are 2200 scopes even lower spec than my disabled 2215 ! LOL  I mean, there are 2200 models that don't even have a delayed time base to start with !  And some even have a lower bandwidth, 50 or even 20MHz ! So... my 2215 is still useful as a backup scope, or for when I want to make "risky" measurements, ahem... 
And the SMPS is completely silent now, so nice to use just because of that !!!  :)

So... that's it for this little 2215 ! Learned a lot while studying its schematics for hours, especially the delayed time base and auto-intensity circuitry.
Delayed time bases are not longer this mysterious and magical thing any more !  It's actually quite simple... quite clever... it doesn't take much at all to implement this marvelous feature... every analog scope should come with that as standard !

As for the rare auto-intensity feature found on this 2215, which was one of the main reasons I bought it, was curious about this feature... well I will have to join the bandwagon of those who said "never again, no more" ! LOL   Yeah, it indeed just doesn't work that well, it's more of a pain than an asset ! And it just makes the intensity control circuitry twice as complicated as in any other scopes, with interactions with the focus control and sweeping... it's just a whole mess that's not worth it, in practice.  So I have my answer now : YES, auto-intensity did exist on analog scopes.... but no it was not worth it and was happily and quickly dropped !


So... this is the last time I attempt such a desoldering job... I will definitely invest in one of these popular Hakko desoldering guns. Hopefully this will save the life of the next such board I try to remove...

I really need to stop spending money of old gear for a moment, and rather concentrate on improving my soldering gear and test equipment, so I can do a better job at fixing stuff...  I feel I am just butchering stuff for now, with my cave man gear.

Anyway, after getting side tracked by this 2215, I think I can now come back, at very long last, to finishing the restoration of my old 317 glowing Tek. Poor thing has been waiting for 7 months now ! Feeling ashamed....  :--
« Last Edit: July 28, 2018, 01:02:24 am by Vince »
 

Online tautech

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Re: Tektronix 2215 Scope repair
« Reply #70 on: July 28, 2018, 12:50:14 am »
 :)
It will nag you for years if you don't try to recover it !  :P

I'm sure you can given a little time to think about it and devise a cunning plan.
Vias, who needs them anyway, isn't it only a 2 layer PCB ?

Can you remove them from the pins and reinsert them ?

Maybe replace the pins with a 90o header set.

Lots of ways to get yourself out of this little pickle.  ;)
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Offline particleman

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Re: Tektronix 2215 Scope repair
« Reply #71 on: July 28, 2018, 01:17:05 am »
Mouser sells eyelets for plated through hole repair.

https://www.mouser.com/Search/Refine.aspx?Keyword=keystone+eyelets
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #72 on: July 28, 2018, 01:18:52 am »
Hi Tautech,


Well...  I guess I have nothing to loose and could use this 2215 to practice PCB repairs ! LOL   Why not... this scope was meant as a test bed to begin with any way, so let's extract as much "eduction" out of it as possible, eh ?!  ;D

OK I might attempt to repair the PCB...  Yes I can removed the 9 vias from the pins, and try to solder them back on.
I have already (straight) headers ready to go on the main board. If I can't manage to stick the vias back into their holes, I could just discard them and just use a simple pad. The pins on the board would be enough to connect top and bottom sides anyway.  Hell worse case, if I can't put pads back onto the PCB, I could just run a short piece of thin wire from the header pins, to the remains of the nearby tracks.

Main problem though, would be physical access to the main board in order to do all this !  >:(

I remove (again) the (main) sweep & amplifier board, that would improve things a lot I think.

OK I might look into this...
 

Online VinceTopic starter

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Re: Tektronix 2215 Scope repair
« Reply #73 on: August 17, 2018, 09:12:58 pm »
Alright.... Tautech, thanks for pushing me into repairing the broken pads/PCB... because once I had stopped crying, got some sleep, went to have another, calm look at the "situation" and well... it's not at all as bas as it seemed, plenty repairable ! :D

Out of 9 pads that got ripped/sticked to the daughter board connector pins... 6 were actually connected to nothing on the main PCB ! These were just lonely pads that served no purpose, other than helping with mechanical rigidity I mean, I guess. But there is already a plastic clip atop the board, that holds it to the SMPS shield anyway. So not too bothered by these pads, nothing to repair in fact.

So 9 minus 6, that leaves us with 3 pads to repair on the main PCB... so let's look at those in detail... see picture : good news again ! :D  I don't even need to repair these pads (not equipped for that and access is not that great anyway, with the board mounted in the chassis), because the tracks coming off of these 3 pads, don't go very far until they reach a via !  So, all I need to do it solder a small one inch or so mod wire, into these via, then solder the other end straight to the header connector pins, once it's soldered to the main board... and it should work I would think !  ;D

Before soldering the header connector to the main board, I had a good look at all the solder joints on the daughter board, and indeed most joints don't inspire a lot of confidence. Dull looking and with so little solder in them that I wonder if Tek was trying to save money on solder to make this bottom of the range scope even more profitable for them... maybe they ran a contest in the PCB workshop : the Tech that manages to set up his wave soldering machine to use as little solder as possible, gets  a 10% salary increase ! LOL

One of the joints had so little solder that it hardly filled the hole in the PCB...
Said joint was on some component that I had never seen before but that I assume must be a resistor of sorts, given its looks : a hollow mandrel with coloured dots, the size of a 1/4 W resistor, that looked like it belonged to a much older vintage, looked out of place in an '80's scope.. But.... according to the silk screen and the schematic, this thing (see pic) is actually a capacitor ?!  Well, I learned something new today  :o

I don't how they manage to make a capacitor out of a hollow mandrel ?!  Do they wrap just a couple turns of thin film around it, so that the overall thickness is still "slim".. if so, I guess the values they can achieve with so little film wrapped no the mandrel can't go very far... 1nF tops ? A few hundred pF ?!

Anyway, I went to start fixing the 3 broken pads, then tried to fit the header connector I had ordered the other day.... STOOOOP ! Header doesn't fit !
Eh ?!  Grrr ! Stupid me ! This old through hole scope, I just assumed the pin pitch on the board was the usual 0.1" , so ordered the usual 0.1" header to go with it.  That will teach me !   Looks like the pitch on the board is exactly 50% large than the 0.1" connector. So I need to find something suitable... hoping it is still available.

Grrr.... I was so persuaded that I would have the scope going again this evening... not ! 

Getting closer anyway...

See you in a bit, once/if I can source a suitable connector...

 

Offline particleman

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Re: Tektronix 2215 Scope repair
« Reply #74 on: August 17, 2018, 09:24:42 pm »
looked out of place in an '80's scope.. But.... according to the silk screen and the schematic, this thing (see pic) is actually a capacitor ?!  Well, I learned something new today  :o

They are temperature compensating ceramic caps. Otherwise known as dogbones.
 


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