Tektronix TDS 744A teardown and repair 2

Рет қаралды 12,571

19 күн бұрын

I continue working on the 1990s Tektronix TDS744A digital 4-channel 500 MHz oscilloscope. My plan was to fix the colors, but I ended up taking a closer look at the switching power supply board, testing and replacing a lot of high ESR electrolytic capacitors, fixing a board damage from electrolyte leakage and relubricating the fan. I did some experiments with the sequential color system. The color shutter has no voltage going into it. There's definitely a problem in its driver, but the shutter itself might be deteriorated too. For now, I decided to remove the color shutter. This gives me a bright monochrome picture. The oscilloscope is perfectly usable this way. I might try to put the shutter back in and fix its driver, but I'm not sure I want to spend my time on it, risking an accidental damage, as this oscilloscope is perfectly usable as it is now. This old Tektronix oscilloscope uses a CRT-LCD hybrid display technology - a monochrome CRT tube with a solid state sequential color filter (liquid crystal color shutter / LCCS / LCS / NuColor).
The 1st episode:
• Tektronix TDS 744A tea...
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Пікірлер: 99

@1pcfred 18 күн бұрын

It is amazing that scope was working with that big skid mark burn in the board it had.

@LawpickingLocksmith 18 күн бұрын

Still a good score. 500MHz is not cheap even technology changed a bit. I am still fixing my 100MHz Hitachi analog.

@DiodeGoneWild 18 күн бұрын

I plan to fix a 2 channel analog 120MHz dual time base BM566A ;)

@a.lisnenko 18 күн бұрын

The oscilloscope is interesting. Please continue!

@amydamon2323 19 күн бұрын

I always learn a lot from your videos. Thank you for making them "bloody long". Two nice things about your videos are that you don't repeat yourself half a dozen times and don't teach us the same basic things in every video. That saves your videos from being "excessively, redundantly bloody long". Kudos for that. Keep up the good work!

@2001pulsar 18 күн бұрын

Maybe a cheap LCD display running from the VGA output would look OK.

@eskisful 20 күн бұрын

I want to see you replacing those timers with rotting batteries inside.

@barbudoru 18 күн бұрын

I highly recommend Necroware's method to refurbish those RTC nvram modules, he recently published a video called "Let's talk about RTC options once again" discussing the topic.

@DiodeGoneWild 18 күн бұрын

Thanks ;) interesting video. I think the RTC (DS1486) already has the battery discharged, as it says the year is 2040. I don't think a clock is that important for the oscilloscope. But the BQ4015 is the NVRAM, it might be more important. But does it really contain the callibration data? Isn't it just for the user settings, to remember things like time base, voltage/div, maybe the color settings for the display. But I guess this one still works as the brightness settings are still remembered without mains. But the most important thing is - were they really that crazy to put the callibration into NVRAM? Isn't this in some EEPROM (flash) instead?

@barbudoru 18 күн бұрын

@@DiodeGoneWild The DS1486 also has a small amount of NVRAM in it, which was used in old computer mainboards to hold the BIOS configuration. I wouldn't exclude the possibility of having the calibration constants in NVRAM, the battery life on this kind of module is >10 years, some still work after 20, so they probably considered it "good enough".

@SimonBauer7 18 күн бұрын

0:57 maybe make a pass through cable, so that one side plugs into the scope shutter and the other into your cable which plugs into the scopes control board?

@Fluxkompressor 17 күн бұрын

Watching you solder with that sledgehammer of a soldering gun expecting total incineration I must say: Best solder job I have seen with the tools given Imagine what you could accomplish with a proper soldering station!

@trebushett2079 18 күн бұрын

And then, for something completely different, he brings in a thorium mantle and geiger counter!

@hempbear 18 күн бұрын

If a CRT is fed way too high anode voltage it starts producing X-rays. I guess that he was checking

@AllLoudNation365 18 күн бұрын

"Changing these crapacitors..." lol

@drobotk 18 күн бұрын

That caught me off guard lol

@atoptip6193 8 күн бұрын

One of these days we will find that his English is actually native, that he also writes comedy sketches and the accent is all for entertainment!

@AllLoudNation365 8 күн бұрын

LOL

@madscientist15808 20 күн бұрын

Nice vid. Maybe you could try to solder some thin wires to the connector of the color filter and route them to the outside of the case. This way, you can reassemble the oscilloscope and still have access to the signals. Also @ 3:42, fully agree with you, I feel the same way.

@beatrute2677 19 күн бұрын

damn man, tough fix this one.

@jeroenjeroen 15 күн бұрын

I like the more extensive videos; if people don't want to watch it, let them be. I'm sure more people like to watch videos in depth!

@user-mz1uh4ju1n 18 күн бұрын

Corona OK, WTF IS THAT 🤣 I think that it means the corona discharge of the CRT but still funny 😂

@daniloxyz 17 күн бұрын

Don't run the thing for too long without a case on, or the airflow from the fan won't reach the ceramic hybrids, they will overheat, expand, contract, and the solder joints of the relays will crack. Ask me how I know... Btw, try to run the Signal Path Calibration. If it succeeds, it will compensate and calibrate all channels (e.g., weird offsets, tiny differences in amplitude, etc.) and confirm the scope signal path is 100% working. If SPC fails, there may be some lingering problem in the hybrids (or somewhere else on the bottom board) and a reflow of the solder joints goes a long way. Also, there are scripts that you can put on a floppy to hack it with all options, but it seems you already have most of them. Nice donation though, particularly because the most expensive part is the 4 probes...

@michaelturner4457 18 күн бұрын

Tektronix would have had jigs and cable extenders for testing and repair.

@jbuchana 18 күн бұрын

Exactly my thinking. I know they had them for much earlier models, as I had them and used them when repairing 545A and similar 'scopes for resale back in the '80s. If my father were still alive I'd show him this video, he was a service technician at Tektronix from the '60s through the '90s. He'd probably have some insights. Great video!

@CJWarlock 16 күн бұрын

@9:32 - "crapacitors" (a new word for crappy capacitors) - Ha! Ingenious! :D Congrats on the funny wordplay. :)

@VIPINSAINI_20 13 күн бұрын

it was nice, i would like to see this again like part 3 of the video

@GadgetUK164 18 күн бұрын

Brrilliant! It would be cool to revisit the colour shutter stuff! And those Dallas chips really need dealing with - you can either retro fit a battery holder to each, or remove the plastic casing which holds the battery onto the top of them (there are a few videos on how to do either mod) - but backing up their contents might be required, unless they just hold calibration data?!?

@Sloxx701 16 күн бұрын

This era of Tek scopes from the 90s are notorious for having bad caps everywhere, I've rebuilt a TDS 420A and a TDS 540 and it was the same issue and some were leaking. I ended up just replacing all capacitors throughout the scope, probably around a hundred of them. Not a difficult repair, but time consuming and expensive. These scopes are not bad for what you get, if you can get used to the clunky, lagging menu/interface design.

@pietskiet3595 18 күн бұрын

KZfaqr Necroware did a great video on reworking those old RTC modules - kzfaq.info/get/bejne/m8mEjdeLzaudkn0.html He removes the chip and soldered in cell and crystal and replaces them with a battery socket. Also a good idea to solder a socket into the board while you're at it.

@wolfrobben6914 18 күн бұрын

Bloody interesting!

@tajtrlik1111 18 күн бұрын

Ďakujem za ďalší diel z tejto zaujímavej série, kľudne v nej môžeš pokračovať a rád sa pozriem aj na ďalšie diely, ak ich natočíš. Ale pekne si ten osciloskop dal dohromady, teraz ti môže pekne slúžiť a štvorkanálový digitálny osciloskop, to je aj dnes dosť drahá záležitosť a takto si aspoň získal pekný kúsok do dielne.

@mikeb1013 18 күн бұрын

Great work, well done. Although it is a shame to now be just black and white, that shutter took so much light I'd just bin it and move on. If it was me I'd get some clear acrylic sheet and cut a piece to stick inside the front bezel and just leave it at that.

@edic2619 16 күн бұрын

Great video. Thanks.

@michaelwittmann3176 18 күн бұрын

Nice video sir please continue making long videos :)

@Alchemetica 18 күн бұрын

As it is I would take it as a win giving you a useable 4 channel oscilloscope. If you do at some future date tackle the colour it would be interesting, but as you said it is working and further investigation may create problems.

@German_byte 17 күн бұрын

Thanks. Btw I love your Soviet era soldering gun. Nice.

@SuperHaptics 18 күн бұрын

I am the guy who is screaming about your soviet era nuclear plant soldering iron😂 . I like your videos mr wild diode, also your crazy soldering iron. Say hi to your lovely cat....

@AKG58Z 12 күн бұрын

21:21 loyal viewer.

@stalkerfromvoronezh4493 18 күн бұрын

ЖК кристаллы возможно уже просто потекли со временем. Так что эта штука в любом случае под замену. Были у меня часы старые с ЖК экраном - так вот, он так потёк, что полностью перестал работать. Клей в старых ЖК экранах со временем разложился и всё. Кина не будет.

@Roman00744 17 күн бұрын

For measuring points you don't have access to you can solder thin wires to those points and then measure them when it's assembled and working.

@adrian_sp6def 18 күн бұрын

You could check if there is possible to find a composite video signal along with chroma and luma, maybe with that You can generate video signal for external monitor. at that moment there is unclear if color generator circuit is working

@thecriss88 18 күн бұрын

There are two type of videos you need to do. One is an SMD soldering tutorial with a gun soldering iron. The other is some political discussion about the current issues in Europe.

@_________________404 17 күн бұрын

Based

@niki1245781 8 күн бұрын

Zdravím, určitě bych byl pro pkračování a další pokus o opravu :)

@farzinfirozian2722 18 күн бұрын

glasslinger has a vidio about back uping this kind ossiloscope cheaps.

@TheDefpom 18 күн бұрын

lol @ 8:45 you know me too well.

@Alexelectricalengineering 20 күн бұрын

That's so awesome 😎😎👍👍👍

@hugoegon8148 18 күн бұрын

Similar pain is to work on car radios or multi media systems because of the compact design. 😕

@Alchemetica 18 күн бұрын

Thanks! Cat treats : )

@inseries5494 18 күн бұрын

you come for the cat

@sigataros 18 күн бұрын

@@inseries5494 the cat proofreads the schematic

@DiodeGoneWild 18 күн бұрын

Thank you for your support!

@graxav 18 күн бұрын

All the way to the end .. I'm as daft as you are .. 😜

@radionicretrofit 18 күн бұрын

We need more scope content

@DiodeGoneWild 18 күн бұрын

Well, I have 3 more scopes to fix ;). Tesla BM566A, some tiny soviet scope and Křižík scope. And probably another Fnirsi to review.

@radionicretrofit 18 күн бұрын

@@DiodeGoneWild looking forward to it

@atoptip6193 8 күн бұрын

Do you think the display of this oscilloscope can take an external VGA signal and show a TV picture?

@app0the 17 күн бұрын

I wonder if the color board is removable then the firmware might know something about detecting it? thus unplugging it might make the display more sensible for a monochrome scenario

@lmwlmw4468 15 күн бұрын

Nice.

@AnnaVannieuwenhuyse 13 күн бұрын

Your DPOX180H forgets its settings? Mine defaults to 10X, as I saved the settings to the defaults as such. You can save settings as default in the system settings tab.

@yan7382 18 күн бұрын

But these oscilloscope have an VGA output connector I believe, you can reuse it to replace the CRT or just use with an external monitor.

@adrianking19911991 18 күн бұрын

These Dallas chips was commonly used as integrated RTC chips for (mailny cheap variants....) AT PC's clones, from 286 era, up to end of 486 era - later Pentium mainboards had in general RTC constructed in other way, and utilized in 90% of PC's much more modern chip, and CR2032 coincell baterry as a backup.... And yes - these Dallas abominations, had INTEGRATED coincell battery inside (technically this is not even a IC, this is PCB with battery, chip, some passives, melted in black resin/plastic...). Nowadays practically every of that Dallases are flat... Some devices, refuses to boot when this RTC battery inside is flat, and spares for this Dallas is nowadays very weak available - and nobody knows how long will work, because these coincells have some lifespan, even not in use. Fortunatelly, there is some modern projects, to replace this with chip + battery holder. There is possible too, to drill a hole in this (yes!), and solder wires for "external power", but.. this is a litte bit "ghetto mod" ;) Greetings from Poland.

@foobarables 16 күн бұрын

You should als check the 5V rail capacitors for leakage. They might be leaking as well.

@kapegede 18 күн бұрын

40 minutes well spend. This length is no problem at all.

@Harry001by7 18 күн бұрын

Even showing the reasonable capacitances but high ESR might be intended?, or replacing with low ESR ones causes any inrush ?

@t1d100 18 күн бұрын

👍👍👍👍👍

@thevoidedwarranty 18 күн бұрын

That LCD module itself is clearly bad ,it shouln'd be spotty like that

@inseries5494 18 күн бұрын

So the one-fix-all decap didn't work! Syuper Niice!

@git-push 17 күн бұрын

I prefer it without the filter on. Btw, it's almost always elec capacitors fault..

@video99couk 16 күн бұрын

If you have a short persistence of vision, as I do, these colour shutter displays are hideous. Horrible flickering display, great way to trigger a migraine. I can't believe they ever released this product.

@DiodeGoneWild 16 күн бұрын

All people have about the same persistence of vision, but some are more easily annoyed by the effect sequential color displays create when they move their eyeballs rapidly. It might be annoying, but it gave it a better resolution than a tiny color CRT would have.

@video99couk 13 күн бұрын

@@DiodeGoneWild I don't believe that's true. Back in the days of CRT monitors, I could see glaring 60Hz flicker on a display that some co-workers literally could not see at all. Similarly when we had one of these 'scopes, it made me feel ill but some other people didn't even see what I was talking about. Including, of course, the salesman who sold us the thing. We did get an HP 'scope with a colour CRT but that thing was absolutely huge, heavy and strictly lived on a cart.

@luich1288 6 күн бұрын

Nichicon are good japanese capacitor. A step under nippon-chemicon but very good

@rc_racing1743 18 күн бұрын

14:35 oh hey, welcome to the future

@imanshojaee5109 12 күн бұрын

Can you try to retrofit an lcd display?

@DiodeGoneWild 12 күн бұрын

Why would I ruin such a cool machine by putting an LCD into it?

@imanshojaee5109 12 күн бұрын

@@DiodeGoneWild to have colors again?

@snik2pl 18 күн бұрын

There were comments to do lcd mod. This crt is for 90% vga monitor

@clusterstorm9522 16 күн бұрын

"Post apocalyptic capacitor"😂😂😂

18 күн бұрын

please do another episode

@janikpaul1808 17 күн бұрын

part 3 pls😝

@meherhjb7170 16 күн бұрын

8:46😂😂😂

@sanitaires 18 күн бұрын

Fnirsi требует сохранения настроек. FDD 3.5" проверили?. Лучше снимки экрана использовать. Тёмное стекло вместо фильтра. Может проще LCD монитор встроить?.