You must log in or register to comment.
Datasheet websites do that a lot. If it’s PDF.js, Firefox’s PDF viewer (or a fork of it), I just right-click to “Show only this frame” and it goes fullscreen. It might have shenanigans such as disabled printing but you can press Ctrl+Shift+E and reload to check network activity for what address the PDF is loaded from and save that.
The worse ones are PDFs that exist only for SEO and contain nothing but keywords and a link to a paywall.
Finding datasheets and service manuals is a nightmare. So many websites claiming to have the right file, only to end up being a scam and not having any files. Having files they have no right to and are publicly available behind a pay wall. Having weird online viewers instead of just giving the file. Padding the file with extra pages of nonsense so they can claim more pages and a larger file size. Having the wrong file mislabeled. Etc. It goes on and on. And then there’s the sites that redirect a thousand times and then crash the browser. I hope I didn’t just get a virus or something.
All I want is to fix this old CRT from 1981 so I can enjoy it for a few more years, is that too much to ask? And back in those days they actually cared about repairability. Especially the services manuals with scope traces for the test points save so much time troubleshooting.
Archive.org is a good place luckily. If it isn’t down because shit heads can’t behave on the internet. As a species we really like to get in our own way all of the time.
And no I still haven’t fixed up that CRT. It is working now after replacing two weirdly behaving transistors, a new power cord and a new power button (old one worked but didn’t stay on unless you held it on). Replaced a few caps but most tested fine, good quality caps. Even the once I replaced were working, but marginal on the ESR. Cosmetics are also good, but there is still an intermittent fault with it losing horizontal size adjustment. It goes from fine and perfectly working to a little too narrow without any adjustment. 90% of the time it’s fine, 10% of the time it’s faulty and it switches random. I’ve been going mad tracing where the issue is, but I will fix it one day.
I assume datasheet websites just have pages for every combination of 3-12 alphanumerics to appear in search results, and then use shitty fuzzy string matching tactics to find “most relevant” items. It would help if they managed to extract package marking codes from datasheets so you can find SOT-23 parts by their 2-3 character codes, or whatever obscure system used by individual IC manufacturers. I think they have resources to make the experience way better but they prefer to turn high profits. Personally, I would not mind trying AI (not neccessarily a LLM) for the data extraction but I’d be cautious and only release it if it is decently reliable (but I know they wouldn’t bother with that).
Pretty sad that a technical manual for the monitor was most likely created but just not digitized in a way you can find. Intermittent faults are very hard to diagnose. What I would try:
- I assume you’ve cleaned the potentiometer, which is also easy to check with an ohmmeter (mind the polarity or desolder it to protect the rest of the circuit).
- Poke the circuit board with a non-conductive object to find loose solder joints or components with bad contacts inside. If the fault is not mechanical, it might be an overheating component.
- Try adding a fan temporarily to see if the fault appears later, or use a thermal camera to find semiconductors that might go near their threshold temperature (150 °C for the silicon die).
- Find points in the horizontal deflection circuit where voltage or waveform changes as the fault manifests.
Yeah the pot is fine, that was the first suspect. Cleaned it and even thought of replacing it, but it measures just fine.
I’ve found several versions of the service manual and combined them to get the info I want. Both seem to be parts of a larger manual, which I can’t find.
I’ve been probing and scoping for hours over the past months. But when the CRT is apart that’s kinda hard, since it has a lot of high voltage I want to avoid. No worries, I have the tools and the experience to work with these things. Over my professional and hobby lifetime I’ve fixed over a hundred CRTs and worked on/designed/built hundreds of other electronics.
I took out a couple of transistors (this thing is almost all discrete components, no integrated stuff) in the horizontal deflection path and tested them and they seem fine. I hooked them up to a function gen and a scope and tested them within parameters. That’s how I found and replaced two other transistors that were dodgy and bringing the thing back to life to start with (it had fully collapsed vertically).
I checked every component in the horizontal deflection path and they all seem fine. And since the thing works most of the time, I suspect they are fine. It might be mechanical, but I’ve tapped all around and that does nothing. If the issue shows up, it stays like that for a while and then randomly disappears again. Only for it to randomly come back.
I’m pretty sure it isn’t a thermal issue, it’s a small CRT which doesn’t use a lot of power and doesn’t really get hot. The issue also appears and goes away randomly. And with the parts open on my bench it still happens. I’ve blasted the entire horizontal path with hot air in case of some cracked solder or something like that. But it still happens.
I suspect it’s actually one of the other circuits that throws off the horizontal deflection. Probably something shorting or close to somewhere. The weird thing is, it doesn’t collapse, it just loses horizontal adjustment. It’s as if the pot is bad, but the pot is perfectly fine. I’ll have to get out my notebook, print out the schematic and start drawing it out. That usually does the trick to get my brain to figure out what the actual issue is. Somehow even after using computers for so long, I need to revert back to how I learnt it in school back in the days to fully engage my brain. Computers probably are too easy and make me lazy.
Well, you have a lot more experience than I do. I don’t think I can provide good advice but the idea of another circuit borking it is interesting, I’d put voltmeter(s) on the supply voltage(s) of the deflection circuit and check for changes.
Please don’t call the unit “CRT”, it’s weird to read phrases like “when the CRT is apart” because you can’t really make a tube work again if it’s been apart.
However, it makes me think if one could smash all tubes in a vacuum tube TV in the vacuum of space or one big glass chamber and have it still working. Or build a monitor into a tube that looks like an overly long CRT but just needs power and video. Maybe even include an IR remote receiver for digital picture adjustment. This is way beyond what I will ever be able to do, though, and there is little reason to make this gimmicky thing that is worse than Philco Predicta (TV model line with CRTs outside cabinets) in almost every way.
Yeah totally correct. The CRT is only the tube part, the whole thing is the monitor. But when I call it monitor people automatically assume it’s like an LCD. So I would have to call it CRT monitor, but that’s a lot.
I will post a vid of the thing if people care.
Edit: Posted it https://lemmy.world/post/20980504
Wow I had no idea about this. And I was just in the process of trying to download a pdf from one of these websites. Thanks
but if they just gave you pdf, how would they track every mouse movement for their bullshit metrics?
would somebody think of the advertisers?
Advertisers? Think of the managers! Managers are nothing without their metrics.
No, it should obviously take you to “pay us enormous amount of money every month” page first.
Suck my InterLibraryLoan, Pearson.
suck my pear, son
https://…/epdf/… -> https://…/pdf/…
Works for some places at least. Super infuriating though. Why use the fast native PDF viewer in the browser when you could use a bloated and buggy JS app?
Very informative, but I’d change one small thing.
Why use the fast native PDF viewer
in the browserwhen you could use a bloated and buggy JS app?Fair, but certain corporate-mandated client-side PDF viewers are… bloatier. Though, I do like not having another window to manage when I open in browser, particularly when doing web searches. It pairs well with tab grouping extensions, and I generally don’t use markup, so no loss for me there.
Oh boy, I sure am excited to websites hosting PDFs! I love when the tool that everyone uses for hosting and viewing HTML get to be blessed with the perfect format that is PDF!
I LOVE PDFS! I love two column PDFs! I love reading like this!
1 3
2 4
5 7
6 8Instead of like this
1
2
3
4
5
6
7
8It’s amazing and such a good user experience!
I love that PDFs are so difficult to transform into HTML, too. I would never want the besmirch the publishers oerfect one approved layout by resizing the window!
I love that PDFs are so difficult to transform into HTML, too
FYI, if that’s relevant to your field, every new article published on arxiv.org now has a HTML render as well.
And on many older publications, transforming “arxiv.org” into “ar5iv.org” leads to an HTML rendering that is a best-effort experiments they ran for a while.
That’s really cool! What I really would like is a tool that converts PDFs to semantic HTML files. I took a peek there and it seems easier for them because they have the original LeX source.
I think for arbitrary PDFs files the information just isn’t there. I’ve looked into it a bit and it’s sort of all over. A tool called pdf2htmlex is pretty good but it makes the HTML look exactly like the PDF.
Yes, PDFs are much more permissive and may not have any semantic information at all. Hell, some old publications are just scanned images!
PDF -> semantic seems to be a hard problem that basically requires OCR, like these people are doing
Oh nice, thanks for sharing that project. I haven’t heard of it before!
Not just semantics. PDFs doesn’t even have segmentations like spaces/lines/paragraph. It’s just text drawn at locations the text processor/any other softwares inserted into. Many pdf editor softwares just detect the closeness of the characters to group them together.
And one step further is you can convert text to path, which basically won’t even have glyph (characters) info and font info, all characters will just be geometric shapes. In that case you can’t even copy the text. OCR is your only choice.
PDF is for finalizing something and printing/sharing without the ability to edit.
I’ve always called Word documents and PDFs “dead-end formats” (DEF). Once you export your data to them, there’s no reliable way to retrieve your data from them for further transformation like you can for YAML, JSON, XML, HTML, Markdown, &c.
Choose your own adventure PDF! 1, 5, 7, 3, 9, 2, 0, 6, 4, 8! What an ending!
That will be $30.12
Every four weeks forever, or until you try to cancel and realize we’ve set the cancellation page up to just throw errors every time you get close to actually cancelling.
Just email the author and ask for a copy
At least you can usually print them as PDF easily. My main issue is that the page title becomes “PDF.js Viewer - [Paper title]”.
If it’s PDF.js, it’s just Firefox’s PDF viewer (or a fork of it). I just right-click to “Show only this frame” and it goes fullscreen.
well they have to justify the exorbitant amount of money they charge for publicly funded science articles (apart from the obvious reason of thinking about the shareholders)
I’ll just be happy it doesn’t ask me to make an account
Truly. Also the springer nature ones load so slowly for absolutely no reason, and break 10% of the time. I really don’t get what their motivation is, do they think that after I’ve said no, I dont want a web version, I will be happy with a different web version?
Or a virus. It could be an exciting virus.
I use searxng and it has some option that automaticly replaces links wich just give u the pdf based on the doi or whatever its called.
nothing beats having to click the download button twice. it’s my favorite
PDF button? Or time to create an account to get a subscription to access that PDF!
You are welcome.
