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Tobias Klausmann
@klausman@mas.to
mastodon 4.7.2Sysadmin/SRE for two decades or so. Published SF author. Computers, Linux, 70s/80s hifi repair and general electronics tinkering. Vinyl records and Music in general.
Not LGBTQ+ but trying to be a good ally.
Banner picture is a metal bowl filled with glowing charcoal embers with flames atop, photo taken at night.
Avatar is a colorful oil painting, with abstract explosion-like shapes.
223 Followers
91 Following
50 Posts
Joined February 11, 2023
Book Info:
Codeberg:
Replying to
@nixCraft@mastodon.social Not to mention that the original Luddites were not the technophobes that people using thir name as an insult seem to think they were.
I am currently (as in: the last few months, more intensely this last few weeks, evenings and weekends) working on a Luxman LV-117 amp that, for lack of a better description, is An Utter Mess.
Straight from the factory, the wiring is an utter rat's nest, with at least 30 board-to-board cables going every which way through the amp. The main board alone has _another_ dozen wires on itself, point to point.
Mechanically, removing some of the PCBs means disassembling the entire chassis.
On top of all this, this amp has had some hard knocks, including burnt off traces, completely shorted output transistors, broken ±15V supply and shorted front-panel opamps.
And then someone before me worked on it and transposed transistors between NPN and PNP, installed fake "replacement" parts and made a mess of solder joints and lifted pads.
So far my MD-format log of things-that-needed-fixing is 784 lines, 6.5k words, and I am still not done.
What a hobby.
#nowplaying Cujo - Adventures in Foam
Amon Tobin, before he chose to go with his actual name. Jazzy samples, intricate beats and a great feel for groove.
That moment in the middle of an #electronics #repair when you realize you forgot to order four components, you definitely won't get them before next week, *and* you will have to pay extra for shipping because the product value is so small *AND* you can't continue with most of the repair since otherwise you'll have to take everything apart again once the components arrive.
Sigh. I have a _right_ to repair, dammit! ;)
Replying to
@Iwillyeah@mastodon.ie I have personally caused a FEMOSFET (Fire-Emitting MOSFET). Or would that be a metal-oxide-semiconductor fire-emitting transistor?
If you're a graphic designer for the packaging of #vinylrecords and you decide to maximize the difficulty of telling side A from B, or which record is which in a set, you need to stop trying to be so clever. Tiny fonts, not labeling anything, obscuring text by visually noisy backgrounds.... I could go on.
Please don't do it. It's not clever (it's annoying), it's not novel (it's been done), and it's not proving anything except that you hate people with poor eyesight.
end rant
And (in my case) then:
me at 09:59: *gets distracted by something shiny*
me at 10:05: *apologizes for being late to the meeting*
Sometimes, with intermittent symptoms, you gotta do what you gotta do.
#nowplaying Fila Brazillia - Maim That Tune
One of the first albums by FB that I came across, mostly intrigued by the title. It's got some excellent grooves and delightful tunes.
Replying to
@worldsworstgoth@hachyderm.io @wikkit@mastodon.social I too lament the demise of TG. Then again, these days, they'd have all of their profits eaten by copycats.
This Matsushita capacitor is ~50 years old, and should be 47µF/25V, as labeled. Its actual capacitance as measured* is almost 78µF. Yay free extra capacitance! And even the ESR is low!
* Measuring capacity like this is not the same as "this capacitor can perform like this at the rated voltage and other specs". In this particular case, due to being out of spec and the reputation of these caps (they are leak-prone), it will have to be replaced and recycled.
Replying to
@n8foo@macaw.social (cont'd)
It is great for manufacture, in many ways, but I have cursed at many of the above situations where a header+plug would have saved me hours. And on one occasion, a wrapped wire was under so much repeated stress that it detached and sent 230V to the chassis, killing the device.
[/end rant ;)]
Replying to
@n8foo@macaw.social ...until come repair time, when you have to undo it, and the find that a) someone put solder on it b) the wire has gone brittle, so you're left with fragments c) the other end is directly connected to a transformer winding, and you don't have enough cable to re-strip, but the "wrap" part is all bent and mangled from the first wrap and can't be reused.
Granted, one can unsolder the post rather than unwrap, but for maintainability and during diag, nothing beats a good header+connector.
Dear #fedi, I am in the market for a laser cutter. I would mostly use it to cut PMMA. I have some previous experience with a rather large unit at a previous employer, but I have no idea what manufacturers to avoid etc. I don't need large work area, maybe A3, though A4 might work. Outside size is a bit of a concern as I don't have a large amount of space. Ability to cut metal would be fantastic, but that can be a later upgrade.
#nowplaying blockhead - Music By Cavelight
I always find it hard to classify this. Is it hiphop? Yes, here and there. But also Downtempo, but neither of them exclusively.
What it definitely is, is enjoyable.
"Good God Almighty, all that other bullshit is here today and gone tomorrow."
Replying to
@janstraube I am basically combining the SC hardware with the PACVR chemistry:
In the tub is distilled water + Ilfotol (non-ionic detergent). After the usual spin back and forth a few times, I spray down the record with more distilled water, then dry it first with a PVA sponge, and then with a tiger cloth (static dissipative and practically lint-free). Then drying on a rack for a few minutes (not really needed since they're basically dry at this point, but making sure).
I don't often send my #vinylrecords through the wash, but when I do, it's usually worth it :blobtonguewink:
I don't use the official Spinclean method/chemistry to wash them, but my method seems to works at least as well --- and is cheaper and less tiring.
Replying to
@Merovius@chaos.social Maybe ask teh author publisher? Mistakes happen, I once got a proofing copy (basically the last step before the print run) that said at the end:
vim: updatecount=50 tw=78 spell
Oops.
#nowplaying Ulrich Schnauss - Far Away Trains Passing By
Some of the tracks on this are so sweet, prolonged listening can give you cavities. I love it.
Replying to
@ozeng Yeah, I figured, plus who knows what the leakage is, how it behaves with more than a couple kHz etc. It's amazing it worked this long, time for it to be retired.
Replying to
@slothrop@lemmy.ca I believe Tom Lehrer has a song about the responsibilities for rockets going up and coming down.
Replying to
@fehrnetzt Da umme Ecke (Schiefbahner Strasse 28) hab ich mal gewohnt, vor, äh... uff ..zwanzig Jahren oder so?
Replying to
@ollej https://www.youtube.com/watch?v=n02tImce3AE Turns out, the body and fretboard of a guitar don't matter much for tone. :)
Replying to
Once the amp is out of protection, it will happily play for hours on end with no issue.
_Sometimes,_ it will come out of protection normally, i.e. in 5-10s, as expected, though only one in maybe 20-50 powerups. What exactly makes the difference, I don't know. It does not seem to be thermal: even when warm, the amp will behave this way.
Any hints and tips are appreciated :) If you want to dig deep, the service manual/schematic is available on Elektrotanya (or just ping me via DM)
3/3
Replying to
@netzwerkgoettin@konfigurationsmanufaktur.de Inzwischen, in der Werkstatt: "Chef, wir ham die Karre komplett zerlegt, aber wir finden bei jedem Teil, das wir anfassen, neue Fehler."
🤞 dass es nicht so ist :)
Replying to
@lcamtuf@infosec.exchange So bad it's good, indeed: bad for roughly everythin, good for learning about reverse voltage on transistors (and other (N)PN(P) junctions).
Potential (ha!) followup lesson: how do you do this with a PNP transistor? What needs to change?
Bonus question: can this be done with a JFET? What about a MOSFET?
@RefurioAnachro@toot.cat I am sure you could make this a lot more psychedelic and/or fractal :D
Replying to
There has been some elec cap replacement in this unit, so I thought maybe something's undampened/was assuming old high-ESR caps. But adding bleeding resistors here and there didn't really make a difference.
Both channels are doing this, though not with the exact same timing, so it's likely neither a faulty component (then it would be only one channel), nor something upstream (then it'd be more synced).
Plus, I don't know if this amp has always (i.e. before the recap) behaved this way.
2/x
Replying to
@krzk @uecker As you keep @-adding me in your discussion: my only point was that _earlier warning_ would be nice. Even running all .0 kernels can be a bit late as by then, the decisison has been made. It's not _impossible_ to bring a driver back, but I feel a lot of work and time could be saved if people had a way to be informed of driver removals as the relevant discussions happen, then they can chime in. Given the distributed discussion of kernel matters, this currently is not very feasible.
WTAF, @Vivaldi@social.vivaldi.net ? I thought you were better than this.
Replying to
@Merovius@chaos.social It's not great, but I guess 81 is window, 82 is aisle. If they're the other way around the sign is not just unhelpful, but actually sabotaging.
@lcamtuf@infosec.exchange Gotta love "THE SOFWARE"
Replying to
@lcamtuf@infosec.exchange FWIW, my secondary school did teach boolean logic --- but then again, that was in the last three years and I specifically picked the coursework that included it.
That said, the first two semesters of my CS degree (a million years ago) included both boolean and predicate logic (and then in S3, a formal proof helper tool written in Prolog called Mollusc).
https://www.youtube.com/watch?v=8Snp1jttT_E
For some reason, this always reminds me of the "Scenes in a city" sequence in the original Ghost In The Shell movie, about 35m into the movie.
Replying to
...and when you do get all the wires right, you get sense-making plots like this one.
#eletronics #repair
Replying to
@kernellogger One thing that bothers me about this (not that I think it's anyone's fault, or that I have an easy solution) is the people that have a genuine need for these old drivers (like the guy who spoke up about the 905), but that _don't_ follow LKML closely. They will likely only find out about this a year or more later when that kernel makes it to their distro, and then they are SOL and will have to ask someone to maintain the patch that keeps the driver around, likely for lots of cash.
Replying to
@kernellogger Worse, it hurts not just people who really should have the budget to upgrade their hardware and are just lazy --- because they will just run old kernels and happily be vulnerable.
It also hurts those that are trying to not create e-waste when there is no reason to do so. One can argue that newer CPUs are more power efficient etc and thus upgrading is a net positive. I doubt that is true for most peripherals and things like NICs.
As I said, it sucks for everyone, I realize that.
Replying to
@netzwerkgoettin@konfigurationsmanufaktur.de Und wie geht das? Nur, falls ich's mal brauche...
Replying to
@Daojoan
Heartily agreed! While _some_ things benefit from video (like "How do you take apart this thing?", though well made photos do the same), most things really don't need a video and bad voice over.
FWIW, there is this script:
https://github.com/obra/Youtube2Webpage
which converts YT videos to a series of screenshots along with the subtitled text. I have not tried it, so I don't know how well it works.
Replying to
@kernellogger My point about the firehose was that even when testing every .0, it would be the only way for people who use these drivers to chime in before the removal of a driver, and thus potentially avoiding a) work+churn and b) now having an arbitrary series of kernels that won't work for them. IWBNI there was an "early warning system" for driver removals --- though that may invite bike shedding.
I would also argue that it's harder to get a driver back than to not have it removed.