No.138 - Tektronix 2430 Digital Oscilloscope Repair
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- Опубликовано: 1 окт 2024
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Donated to the channel by Dominic from England, this scope had a few errors before it went BANG!
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I went through this with my 2430. You will most likely have to replace the Keeper lithium backup battery and do a full calibration. Before I removed the old one, I rigged up a battery holder with two AA batteries in series and soldered them in place in the hope that it would at least keep some of the constants intact. Not sure if that was necessary or not, but I do know that I skipped some of the calibration steps that I did not have the proper equipment for and everything worked good after I was done.
There is a jumper that is internal to the 'scope that must be switched to allow the full calibration. (I just walked downstairs to check, J156 needs to be removed to do the full cal, then replaced when the full cal has been completed). There is a procedure in the service manual that will walk you through all of this.
Also, these 'scopes are very sensitive to any AC ripple. I originally replaced the RIFA caps in mine (before they exploded, but they WERE cracked) and also that 820uf cap just as you did. I didn't feel that the rest warranted replacement. I replaced the 820uf with a 1,000uf, I think. I kept getting odd glitches and freeze ups. Pulled the rest of those caps in the power supply board and replaced with new. The problem did not present itself nearly as often. With more exhaustive testing, I found that most of those caps were getting electrically leaky, even though they tested in spec. I still would have occasional freeze ups after replacing those caps, just not nearly as often.
After some more testing, I found that those 22uf, 35 volt radial leaded bypass caps that are all over most of the boards were getting dodgy as well. Replaced them and now I rarely have a problem. Just once in a very great while. There is a LOT going on in this 'scope, so I have to wonder if there were not glitches sometimes even when new.
I was going to buy one of these 2430 scopes, and the seller wanted to test that it worked, and when he did one of the Rifas exploded.
He was shocked, and said he couldnt sell it as it was broken. He just had to throw it away.
End of story, I got it for free. Changed the 2 Rifas, and everything was ok.
My 2430 had the same errors (after I fixed the fallout from the battery leaking). As I recall I had to "Cold Start" and then do a couple of rounds of "Self Cal" before the 7-8-9000 errors cleared up. You may also want to take a look at the battery on the CPU board. It's easy to get to, and you can measure both the voltage and the current draw (voltage drop across a 10k resistor in series), see how it's doing. The FP processor detects when the battery is low, but on mine at least, the FP went incommuncado if the battery was low.
The screws are because the rear feet are missing, which take up the extra space.
yes true , might have been rack mounted at some time or just got broke and then removed
I had to replace a bunch of caps in the power supply in the 2432A, ripple was blowing tantalum’s on the digital PCBs !
I could almost smell the Rifas from here - terrible smell! I was going to suggest changing the NVRAM (Dallas) chip first but I noticed the NVRAM checksum test is passing, so not that simple unfortunately. That odd waveform looks like one of the diagnostic test waveforms indicating a possible switching problem in the front-end? Regards, David
Interesting.....Thanks!
Textbook photo of some of the best that the market had to offer back in the day, these Magic Smoke Dispensers came in all sorts test equipment and became legends in their own lunchtimes. Their unrivaled ability to remove moisture from the air and increase their own volume to accommodate that moisture will not be equaled. All in a day's work for the 'Rifa' ! these and other features are the reason why they will forever be cemented in history as the true masters of 'Magic Smoke Dispensary' ....cheers.
Turning your electronics into impromptu stink bombs, because who doesn't love the aroma of charred plastic and a hint of burnt toast wafting through their workshop?
Yes, RIFA capacitors: The only component that can make your electronics double as a high-tech air freshener - if the scent you’re going for is Eau de Electrical Fire!
@@IanScottJohnston :)
First of all I suggest to re-seat the components in the path (opamp in socket if they are) and double -check any mechanical contacts. Second most probably bad component is any of the tantalum caps. And third rest of the caps. Looks like many errors are related to gain ... then focus on the input amplifiers :) And thanks for video :)
Deja Vu experience for me, my eBay purchase Tek 2465B scope decided to let the magic smoke escape, yes, the RIFA cap committed suicide!
It had swelled to a fat cracked plastic bubble.
After cap replacement, be sure to check the low value resistors across the AC PSU filter inductors, and thermistors…
The scope may work, but the R’s get hot! They were double nominal value. Ask me how I know…😳
Cheers! Steve
It's a CONVENTIONAL scope, I know I used tro use it. It has CRAP storage ability, pretty good at the time.
Theres a 3.7volt battery in that scope that stores the calibration.
You might consider replacing it before it looses it's stored data.
Got a 2430A a couple of weeks ago. The Rifa's were all OK, as was all other components, at least as a visual. But after a hour of operation, the smoke went out. And the mains got shorted. Yeah the net filter let out, quite a lot black sauce... Really smelly indeed! So these filters do seem to be worse than the Rifas, at least in this scope of mine...
You simply can't get better than one of those tek scopes. My 2236 is ancient but I wouldn't swap it for a top end modern scope. Whether the caps measure good or not, ALL of them should be replaced in these scopes. I was told this by an ex Tek tecnician.
Regarding the calibration failure, try the NVRAM battery?
It seems a CCD problem. Tektronix did not sell CCD as spare part because there could be compatibility issues with the boards if you replace only the CCD. I changed one in a 2432 and it was impossible to fully calibrate it
2430a my 1st storage scope , and iam constantly scared its going to die so ive got a complete 2430m for spares + extra spares too ,so far its had 2 new (used) trigger chips new mem batt and a backup made of all eproms, full recap of the lt psu and hv psu and all the hybrids removed and sockets and silver hybrid pads cleaned with ipa
being my 1st digital scope i was confused by the apparently high "noise floor" thought it was a fault! and i didnt know about aliasing so i wonder if it really needed those trigger chips at all! at least i kept the old ones
but one bit of advice =the ccd,s run hot as hell so its very bad to run these with the case open because the fan wont flow without the case to duct the air ,always use a desk fan or 120mm pc fan facing the ccds when running case open. edit i have a habit of comenting before watching to the end sorry!
currently the astig needs adusting every boot from cold and the on screen menu/readouts disappear when hot but its so complex to look into that, need to build up motivation ,a 2245a ,2246a and a siglent sds1202xe are my daily drives
Brilliant so far on this one =D
I also have an 3430 and the weired waveform will go away if you press the aquire button on the top right it always starts in a halted state. Then it should work normally. And restart the scope after the calibration.
I wonder if those resistors in series with the RIFAs were chosen for their tendency to fail open like that. Keep the RIFAs from starting on fire when they fail short? Maybe a good idea to use fusible resistors instead?
Improving EMC performance, damping high-frequency oscillations or/and reducing surge current?......I'm not sure.
Nice scope! Those hybrids on the bottom board are running very hot - you need to direct a fan to them if you are running the scope out of the outer shell.
Edit: Oh dang, you do exactly that later in the video, nevermind lol
A guess PSU funtime caps went boom....AC filter caps aka X2 film. something about that time those caps have a reputation my Philips scope had same issue as well as other stuff from that time.
Bang and smoke… smells like a Rifa ! I’ve got a shirt design for that ! Power supply is a pain to get to but doable, had to do that to my 2432A
My other Tek 2430A is working fine, but I really need to get inside it and replace the RIFA's there also. A job for next week.
Hi Ian, ya lucky git! if that had been me when the caps blew it would have spiked the board and wiped out half the chips! 🙂. Bob
Edit: oops! I said the above earlier in the video I do hope I haven't jinxed you mate, we will see in part 2. Good luck.
Please part 2 video fluke8846a
@amrahmed6471 I heard you the first time on your comment on the Fluke 8846A video.
I need this video please 🙏🙏🙏
I guess a RIFA popped in my equipment too. Don't know for sure, as it is "enclosed" in a module (IEC socket / Schaffner) but it was not only smoke, also some orange goo. This enclosure was kinda "hot" to the touch. Funny enough the instrument did its job even smoking like crazy till i turned it off. :D But the smell ... oh my the smell.
I had a Schaffner filter blow too (BIG bang), in a Tektronix video pattern generator. I replace them on sight now.
@@Petertronic With a (new) Schaffner? Just from a recent production? Or something else/DIY? I ordered a new Schaffner with just a newer manufacturing date.
@@kevkabluebird1032 IEC socket/filters are hard to find (I don't trust the ones on ebay which look like old stock) so I fit a normal IEC socket with a suitable filter capacitor across L & N. Not as good of course, but better than nothing.
you may have some caps somewhere that drift with temp changes .... first thing to do is recap ... even when caps read good now they will fail later
Interesting video to look inside these nice machines. But next level digging is needed to solve all those error's. Maybe a downside of these vintage machines, if one is not into it, but if you have time it can be interesting and educational to solve. Good luck.
I have had that happen before with a used unit I purchased. It turned out to be one of the chips on the bottom that you are cooling with the external fans. In my case one channel worked and one did not, allowing me to swap from channel A to B.
TEKTONIC scopes are cool for morning exercise
That trace looks to me like failed decoupling caps in the input amplifier section but i'm not an expert on tek scopes. Intrested to see the part 2
Tektronix, Rifa caps, awesome Ian! I enjoyed it. The scope is sooo packed! Nice one.
those CCD chips at the bottom are the common failure of 2430 and of course they are custom made hybrids.
follow the SM and if everything else is ruled out it's gonna be the CCD hybrids which is most likely the case and that will be the end of the road. I had to literally throw out 2 of these because all 4 CCD hybrids on two units were defective. Look for some old videos by Simon Spiers from 4-5 years ago.
I've heard that when caps read over what they should it's most likely because they are leaking and it's taking longer than normal to charge them.
The datasheet for these caps specify -10% to a whopping +50% so I’d guess that’s more likely what we are seeing. You’re not wrong though.
About those "paint splatters" on the front panel and CRT... If the scope was stored in a garage or attic, that might be spider poop and not paint!
Yeucchhh!
I suspect that the front end amplifier modules may be toast, if memory serves me that is common with some of the Tek scopes, at least consistent with the errors. But I am not the expert.
Was afraid of that......
You have to be careful running without a case the hybrids can overheat as they rely on the airflow across them.
There's a couple of fans underneath the scope......you see them later in the video.
It's amusing how hobbyists never bother with grounding straps and lab coats. We had one of these in an old job and you weren't even allowed in the same room as it without a ground strap test. Had to take my non-ESD hat off too.
You are so right!.......And in my case I have an ESD strap anchored to the underside of the front edge of my workbench, it's turned inside out and I tuck it on the inside of the belt of my trousers. I 'invented' this when I was in production of PDVS2mini's. It works well, and if I walk away and forget it's there (I do it all the time!) it just pings out. Highly recommended. I don't own a lab coat though...:-)
www.ianjohnston.com/images/stories/IanJ/ESDstrap.JPEG
As long as you are in contact with the ground of the device before you touch anything else there should be no problem. Luckily almost all is surrounded with ground points.
Be sure to run a fan underneath so as to not overheat the CCD hybrids!
Yes I did......once I was running it for more than 5 mins. You see them in the video.
does it have pesky dallas chips for storing the cal?
Cal at the moment is intact......but if I get it up and running that's something to look at I guess.
@@IanScottJohnston front end hybrids maybe, relays ?
when you tinker like you know what your doing you can impress a women far easier flipping that pcb board than flipping the bonnet of you car🤣🤣
Holy hell! Those really went bang uh! lol
Shaeffer line filters go bang......I haven't heard of other ones.
@@IanScottJohnston Thanks! I couldn't remember the dangerous brand :)
Everytime I see one of your commercial spots I have a urge to "buy their product"... Just saying I also love [any] scope video. So it's a win win. And I concur. WOW is the correct reaction. Techtronics: The SpaceX of their day Failure: I've always been taught: "Don't Fear the Refa" ⚰ I may have to revise that now Thank you for the video. Cheers from So.Ca.USA 3rd House On the Left. (call before you stop by:)
What a complex piece of equipment! And it looks like it's going to put up a fight, Ian. But very much worth it, a very good scope I think. Other than causing more shorts I can't help much, but this was already enjoyable. Looking forward to the next episode. Thanks!