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#6 [Repair/Upgrade] TDS3052 Oscilloscope repair
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- Опубликовано: 31 июл 2024
- A auction-bought scope is non-functional, the error is traced to the switch-mode PSU, which is repaired. The scope is then flashed to the latest firmware and upgraded to all options using an eeprom "hack".
This couldn't have been done without the EEVblog forum member's discussion on the DIY options module:
www.eevblog.com/forum/project...
And GreatScott! has a great video on switch-mode PSUs which clarified their topology for me:
• How does a modern Powe...
Finally, EEVblog did a teardown of this scope (the 4 channel version), which helped me get into the scope:
• EEVblog #564 - Tektron...
You should also note, that this series of scopes could have their bandwidth upgraded via a GPIB SCPI command, which isn't done here as its a top bandwidth model already.
0:00 Intro
1:00 Opening the unit
3:11 What's the issue
4:31 Proving its the PSU
10:14 Removing the PSU
16:23 PSU circuit analysis
17:43 Problem resistor found
25:31 Resistor replacement
27:28 Repairing a pad
28:58 Testing the PSU repair
30:09 Testing the repaired Scope
30:51 How options modules work
33:50 Upgrading the scope firmware
37:02 Hacking the option eeprom module
42:08 Checking out all the enabled options and capability
That envelope tip is golden! Great idea, and, like most great ideas, it seems obvious once you know it! Cheers, mate, subbed!
I like your low key style and methodic way of finding the root problem. Subbed.
Thanks for the sub!
I have the smaller version, the TDS2022. Within a year of purchase it broke down. Indeed the switcher. The heatsink was too small for the dissipated power. I modified it and now it has been fine for several years. Tektronics is no longer the sturdy brand it used to be. Cheers
Your way of arranging the resistors is brilliant 👏
Thanks a lot 😊
I used ziploc. You will see how many resistors were left in the bag.
I bought this same scope bundled with a TCP312/TPCA300 current probe from an auction in early 2020 for $1300. It actually a really great scope. Im waiting on a USB floppy drive so I can upgrade the FW, hope it works. Thanks for the video!
The USB floppy upgrade looks great. I love the scope too and its now my daily driver, I just wish it had more channels and/or more sample memory. Even cheap scopes have so much sample memory these days...
The Chinese are offering this scopes substantial features in 2023 for under 150 dollars. And it shows lol. It kinda does what they say it can do but like all Chinese products it only looks like it has the features. Well it has them but they don't exactly now how to implement them.
I repaired a switching power supply in an industrial VCR, it was that small electrolytic in the startup circuit. there was no indication it was bad until I inspected it under a microscope and saw a little corrosion on the legs. ESR meter found it in just a few minuets after I verified the switching mosfet was good.
43:00 in - "Ok, that's probably fixed it. Turn it on - any smoke?"
Interesting video to watch. Thanx 👍
15V out is for active probe power and that black wire to the mains for line trigger
Great video...cheers.
Thanks 👍
I wonder if they put two resistors in series because of the high voltage. That seems more likely than doing it for power dissipation reasons, or because they didn't have a single resistor of the correct value.
Yes, I agree and well spotted!
I didn't do the math exactly right on video, but assuming the worst case its 240V AC, rectified to 340V DC, then dropped over 780kOhm, this gives the relatively small current of 0.436mA; however, the power is not insignificant at 0.148W thanks to the high voltage. This is fairly close to the 1/4W rating of the resistors I used, and the environment of the PSU might be fairly warm leading to a derating of this (and how I mounted them against the board). I think they stood the resistors up the way they did to aid in heat dissipation too. Overall, I am sufficiently concerned that I've ordered some 390k 0.6W resistors to replace.
OK, I've reread your comment and noticed you mean voltage rating. Some quick googling found this comment online:
"Start resistors used to initiate oscillation in mains SMPS are usually paired in series to better survive the 200-350v they see, and even then, start resistors are a very common cause of breakdown (they eventually go open circuit)."
Which is exactly what failed here and I really should replace them with two resistors in series. I'm a little surprised at this, as you'd imagine they'd have just put the space on the PCB to place two resistors, rather than make that custom, two-resistor thing I removed. Thanks again for the comment, I learned something new.
@@bansci The lack of PCB footprint is because as part of the design as you have already mentioned, the resistor pair need to be mounted vertically just to assist with the cooling as well as load sharing. Karl.
@@karlfell3768 I agree about the design being for heat dissipation, I'm just amazed it's cheaper to do this than to, say, add many single resistors in a on-board network to share the heat/power, or even just buy a single resistor in a higher power package. Maybe the pair of resistors was even purchased as a single part, pre-bent to fit a standard single resistor footprint?
I'll try to make a similar vertical double resistor when the parts come in, I'm not experienced enough to question the design choices on a mass produced PSU like this.
OK, I realise I'm taking this too far, but I found a shot of a NAN40-7608 on ebay, which is in the same family and shares the same PCB, and the startup resistor (R2) is a single board/horizontal resistor in what looks like a 1/2W package.
I think Artesyn just found it cheaper to series two 1/4W resistors at the time of production rather than source a 1/2W resistor.
That's just so crazy. A single resistor causing the failure !
Agreed, Supposedly a common failure mode too, and I didn't think resistors could fail on their own till I saw this
i have tds3032 white screen.no relay noise. i have found +-5v 3.3v. have any idea wheres the problem??
Sorry no, I'm not sure where the split rails are generated, but I'd check for shorts pulling the rail down using a thermal camera at first (because I have one), I'd check if the rail has high ripple perhaps indicating a capacitor problem. Unfortunately it's still wide open at this point!
Is it possible to reprogram the 24c02 without opening the module? I'm wondering what the 6 pins on the module are connected to, and haven't found a diagram for the TDS3XXX modules anywhere.
Yes it's possible, the pads are just taken straight out. IIRC the only on board component is a decoupling capacitor. I think the eevblog thread I link below had done discussion on this. If you're really stuck I can photograph my module
Hah (and Hi from the UK too). I bought the same scope at an auction, also completely dead (which was encouraging... PSUs are simpler than logic boards !). My PSU similarly produces nothing, so I'm in the process of looking at it. Interestingly, there's evidence of overheating around that resistor pair and the larger blue-violet-coloured pair - to the extent that one of the tracks has separated from the board. So that's definitely somewhere to investigate.
Artesyn do newer equivalent PSUs, and I'd thought to just buy one of those, but it hadn't occurred to me that Tek might have designed the second board (called the "battery board" in the manuals because it manages getting power from, and recharging, the optional battery, as well as generating the other voltages the scope needs) around the exact characteristics of the PSU. So thanks for that thought, makes it worth putting some more effort into the original.
Good luck with the repair! I think if I do another one, I'll just follow TheFeedbackLoop and test everything first. He had a hell of a saga repairing the SMPS in a display recently ruclips.net/video/dUlpt3-WJpM/видео.html which might inspire you further.
@@bansci OK - I did some digging this evening and uncannily the exact same resistor had gone open-circuit as on your board. In the same pair of 390Ks, the outboard one. Unsoldered the pair of them, replaced with two new ones, and the creature comes to life. Thanks for blazing the trail ! Now I need to buy a probe...
@@richardt6 Great news! Glad to hear another of these excellent units was saved!
easy instant sub.
Yeah that is the problem with those cheap desolder guns. Your dwell time is usually longer than it should be because, and this is my experience and indeed confirmed by others regularly, the solder gets stuck often in the long tube leading to the collection glass. I speculate (and I want to emphasize it is just speculation) that on the cheaper desoldering tools only the tip is heated. Over time the tube will soak up some of the heat from the tip but often not enough. Solder going down the tube ends up solidifying too soon. On the more expensive ones like the Hakko FR-301 or even the FR-401 heat is applied to not just the tip but the tube also (or at least a larger part) it seems. Reducing the risk of blockages.
Now that doesn't mean you can't damage traces with the more expensive ones ... you can indeed ... but the dwell time is smaller reducing the risk.
As for the floppy, I had to do something similar for my TDS754D, I ended up buying a cheap usb connected floppy. That worked great to my surprise. I wanted to save the data in my scopes 2 Dallas chips (which ... are long overdue for their final failure). Someone on the EEVBlog wrote a little script for that scope (and others like it) that allows you to dump the NVRam to the floppy and also upload it again later. Even seen people who install an SDCard reader that emulates a floppy drive and is a plugin replacement for the old floppy in the TDS.
How amazing is that PCBite thing... Absolute must have thing. The only thing is the Dupont connectors can get a little loose but that is easy to fix with some pliers.
Thanks for the sub!
I only have myself to blame lifting that pad, I was rushing and it's a cheap PCB so I should have been more careful. Interesting point about the hakko handpieces, maybe I can put one of them on my station? I definitely get a lot of blockages like you describe...
I've thought about the USB floppy mod, but so far I don't need the data off the scope. I probably will later though so I might buy the parts in now for when it inevitably becomes essential.
Yeah the PCBite is great, especially the scope probes, so cool for quick debugging. It's just a bit expensive. I've been looking at a few cheaper solutions when I need to debug a parallel bus (so I can need 8+ lines). These probes are great where you have a package leg
m.aliexpress.com/item/1005002931805113.html
And this looks like a nice low cost all in one solution
m.aliexpress.com/item/1005002437962150.html
Thanks for the comments! Off to check eBay for hakko desoldering handpieces now
@@bansci The FR-301 is an all in one desoldering gun. It has the pump in the gun. The FR-401 is a handpiece with separate station. But it is (for some reason) a LOT more expensive sadly. Still I have had 2 cheap stations, an old desoldering gun (all in one too but a really strange one, it did not have a pump but a sort of vacuum cylinder that had an electric plunger).
The 2 cheapos, nothing but blockages all day long to the point where I spent more time on that then anything else. The old All-in-One was better, but still not perfect (and no more nozzles for it anywhere).
The Hakko, o.m.g. It is a day and night difference. With only 2 things I would like to see changed. A led to indicate it is on (visible as it sits in the stand), and a small delay after the trigger is released where the pump keeps running for 2 seconds longer.
@@xConundrumx I'm very keen now to find a better desoldering gun. I've looked at the JBC DR560, as I quite like their 245 irons, but the cost is insane (~£1.2k) for a single station. Even the Hakko FR-301 seems cheap at ~£725. I'll keep an eye on ebay, I'm sure I could fix a broken station...
@@bansci 725 pounds for an FR-301? That's way more than I payed. I can buy them for 325 Euros and even that is more than it used to be. Or are you thinking of the FR-410, yes that one is not cheap.
Don't go for the Weller eco-system. I have the WX2 as a station and while it performs fairly well it has (for me at least) 1 massive drawback. A shocking lack of tip choice. Why this is I cannot say but it is really an issue. If you want desoldering on the Wellers you will probably end up with the WXD2 (or WXD3) which is the same as the WX2 but with a vacuum pump built in as extra.
JBC is expensive sure, but I like their approach better in some ways. It's more modular with more choices.
And then there is Pace, some people swear by them. Myself I have no experience with them.
Not an easy choice
@@xConundrumx yeah I meant the FR-401. I used to be very pro Weller, with my WS81 being my main iron for over a decade. But the lack of primary side fuses in some of their latest kit means they either don't care about safety or they've cost eliminated everything down to the bone. Neither is a good sign!
I've put off the purchase now. I'll make do with my current station until something amazing comes out of China perhaps
Nice video. Looking forward to more like this what part of the UK are you in?
Any chance you could point me in the direction of a source for those obsolete modules? everything I've found online appear to be high priced active modules. I suspect this will be a mobile phone hack - although I'd prefer to use an obsolete tektronix one for convenience
I'm in Scotland at the moment, and I can confirm there's no modules up here unfortunately.
The most professional DIY module I've seen is using a PCB and the contacts from a phone SIM reader, like this
oshpark.com/shared_projects/pE9Ff8iu
I was lucky I could pick up a module cheaply on eBay as they don't hang about! Still, it's not too hard to fill a blank module cover with the PCB. It's the exact same shape as the real module.
Can we use normal probes with this oscilloscope?. It seems there are additional connectors around the BMC connectors.
Yes it's "normal", those connectors are for automatic probe detection on fancy probes
Very very good video....!
I have a TDS3014B, with Flopy Drive, can someone explain to me how I can copy the firmware V4.41 (+/- 2.5Mbytes) to Flopy Disks for make the upgrade of my Tektronix ?
Is this useful? www.tek.com/en/oscilloscope/tds3014b-manual/tds3000-tds3000b-instructions if not, where are you stuck?
when you powered up the scope after the repair, how come the PSU board is still on the bench? did you have a spare?
Well spotted! At the start of the video I said I bought everything I needed to repair it, and what I meant by that was a different second-hand NAN40 series switched mode power supply (with three outputs). I thought I'd have a dead primary transistor or switch-mode controller and thus need some out-of-production part, not something cheap/jellybean like a resistor.
It turns out these supplies have a lot of differences on the secondary side between different models, and between different revisions, so this was a bad idea all round, but that's how you learn.
It was quite interesting as I have a tds3054b which recently had the NVRAM battery die, a dremmel and fine soldering and I've now got a cr2032 holder in it working fine. But even with it "off" but on at the wall, it gets quite warm on the PSU area at the back, suspect a fair bit of standby heat dissipation and those caps won't last forever. So we'll worth watching your repair :)
I'd like to see a picture of that repair, so I googled it, something like this? www.eevblog.com/forum/testgear/crack-nvram-ds1486-ds1650-to-add-battery-socket/
Very cool.
I'm surprised there's a lot of standby heat dissipation, I'll check my scope out, but I think I get nothing noticable. You should try to narrow down that heat to see if somethings starting to leak before it goes pop.
@@bansci yes just like that, although the NVRAM on this series of TDS scope is just used for storing Time/Date and GPIB interface settings. Tektronix Have a document for disposal of this model from military applications where you may require all memory to be blanked, so it breaks down what is essentially stored in each memory device. So it is not a massive issue for these if it does die.
Also it only has one battery instead of two in the device. Same series but different part.
Hello again, i have a TDS3014B, with Floppy Drive and would like make the firmware upgrade, but the firmware file that I have V4.41 is +/- 2,5Mbytes, so I dont know how a can divide the original file in to four floppy disks, like disc1, disc2, disc3, disc4..... Someone can explain me how I can do this process? I have a laptop with floppy drive and new formated and blank floppy disks.... Someone can help ? Many Thanks
I checked out the firmware file, its a zip with four folders each one labelled after a disk you need to copy it on to. I got the zip from here www.tek.com/en/support/software/firmware/tds3000-and-tds3000b-series-firmware-fv341
Hi, did you know about the ability to hack this oscilloscope before you bought it? I find it hard to know what has hidden features when looking at old equipment and I don't think it is very feasible to spend hours and hours researching every tool that goes on auction, any tips on how to get learn about good equipment without the massive time investment?
I don't think there's any special trick, just only research equipment you want and you have a chance of buying. The chance bit is probably what you need to get right. I don't check eBay often as prices are high in the UK. But I keep an eye on the test equipment Google groups and check out their adverts, as usually prices are more reasonable so it's worth the effort. Same is also true for clearance auctions that sell company equipment, you can occasionally get amazing bargains but you must be careful not to get carried away
30:20 Is that a twin PSU I spot there?
If you're talking about the PSU on the bench in the lower right, that's a donor PCB I got off eBay when I thought the issue might be with a switching transistor or some other part. I didn't think it would be a simple resistor failure but now I know better!
If you mean the barrel jack in the back, that's a output for powering some other peripheral, I don't think it can be a power input.
Talk about making money. 300 just became 8 thousand. Eat your heart out Warren.
If I wanted a new one definitely! But I think you can get 500-1GHz scopes for about £500, depending on model/age. I won't be retiring just yet!
Where can I acquire this Omega plugin with all options enabled :)?
You have to build your own! Some of the DIY versions use bluetack, a sim card contact pad from an old phone, and the eeprom chip soldered dead bug style, really nice hackery
@@bansci I dont have the neccassary tools for that. Possible to acquire one Omega from you?
Sorry, but I don't want to get into distributing hacked modules. If you have one of these scopes you should be close to the tools needed (bluetack and soldering iron).
@@bansci I feared that answer :(
@@bansci which programmer do you use?
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Are you using leaded solder? Because unleaded solder isn't fit for repair. You heat too much the pads with your unsoldering iron. That's why you killed the pad. Nice job to find the problem on the power supply, it was far from obvious. 👍
Thanks for the advice and support! I am using unleaded solder, I'll try to get some leaded for testing. I didn't think I'd over-heated the pad too much in this case, the contact time wasn't that long and you need to melt both sides well for the gun to do it's business but clearly results speak otherwise. In hindsight, I should have just clipped the resistor and pulled the leg through the other side without using the gun.
Check the fuse, check the fuse, CHECK THE FUSE!
I already checked it and it was fine. If it was that easy I'd skip making a video on the repair!
Get some liquid solder flux
Replace all the electro caps
That's a lot of work! I'd do it for a calibrator or a precision DMM, but not for a scope if it's still meeting specification
Flumsy and without Organisation