I once had the problem that running make with too many parallel jobs (-j) would change my keyboard layout. The machine was some laptop mainboard glued to the backside of my monitor, and the USB socket came out at the top of the mainboard. On its way down, the USB cable for the keyboard passed across the whole mainboard. On high load, the mainboard created enough interference to cause the connection to reset, re-hotpl…
Check if your IKEA chair is compatible with your screen
161–170 of 214 posts
Re: Check if your IKEA chair is compatible with your screen
#162I turned it on and my screen image started gently moving around.
The fish swam with magnets and having the little tank next to the screen was causing the screen image to move around.
Re: Check if your IKEA chair is compatible with your screen
#163Earlier quoted context omitted.
I currently have an RPi4 mounted to the back of my TV for easy Kodi streaming, but I never considered using the business end of a laptop. I'm sure I have a decade old laptop with a broken screen sitting at the bottom of a shelf somewhere...
Its the stuff what happens when you think 'what can i do with the hardware that i have' instead of 'which hardware to buy'.
Re: Check if your IKEA chair is compatible with your screen
#164Earlier quoted context omitted.
One stupid little thing I realized after having sometimes been consistently zapped by mybcar door and other times not getting zapped in the same weather and humidity: If I open the door and grasp for the (metal) edge of it before I start sliding out of my seat I will be grounded and consequently not build up charge as I leave the seat.
We had some carpet at my old workplace that would always charge you up and get you zapped. Whenever you touched anything metal. So the old and wise folks there immediately told you to grab your key when you get up and then use it to touch something metal, so the spark is between your key and the metal object and you don't feel anything.
For example, we have a few bar stools at home; sitting on one always primes me for getting shocked after getting off it. I figured a few rules, such as never wearing anything isolating on my feet, so I can dissipate charges by keeping one foot on the metal part of the chair; or, failing that, I make sure there's always a metal object in grasping range, which I can use to later discharge in a less painful way.
(Pro tip: don't do the metal discharge thing with the hand you wear rings on, and hold the metal item so it doesn't touch the underside of your fingers - getting a shock through a nerve isn't pleasant at all.)
Another thing: I always keep a metal coat hanger around the bedroom, so that whenever I have to deal with blankets, I can keep "swiping" them to collect charge and then transfer them away by touching something grounded with the coat hanger.
Also: I always have my keys on me when away, in an easily-accessible place, specifically so I always have a metal object I can use to offload static charge in a pain-free way.
Also: over the years I kind of habituated all kinds of subtle behaviors designed to keep me safe from getting shocked by my wife or kids. Basically, if I feel one of them just got charged (e.g. via the blankets or the bar stool mentioned before), or I haven't kept track of their recent movements in a static-rich environment, if there's a need or chance of any kind of physical contact, I instinctively first touch using my elbow or some other pain-minimizing way, just to equalize charges with them. My wife sometimes notices when I do it to her, but fortunately, she is quite understanding.
Re: Check if your IKEA chair is compatible with your screen
#165Re: Check if your IKEA chair is compatible with your screen
#166One of my first jobs 30+ years ago was ESD testing automotive and consumer electronics. I would spend a week with a discharge gun methodically running different discharge energies and waveforms both directly onto the devices as well as onto radiators at various distances from the device under test, as well as any cabling/harnessing that attached to the device. Then the design team would figure out the reason for any…
Re: Check if your IKEA chair is compatible with your screen
#167Earlier quoted context omitted.
Perhaps a silly question, but does turning it off and back on again also resolve the problem? I can occasionally hear such noises from monitors, and have always thought it was some kind of interaction with the phase of the AC power and some kind of internal physics of the monitor. Generally, turning it off and back on again fixes it for me.
In the old CRT days that could be plausible, but in these days of lcds and switching power supplies it seems less likely. But as this article describes, you never know!
When we were teenagers, my friend used to call it "waving a dead chicken". He coined this term to describe the way he would resurrect dead inkjet printers that even I gave up on - by disassembling and reassembling them until they started to work again, while being perfectly open that he has no idea how it could fix the problem, just that in practice it often did.
While this was just a funny term and pretty absurd approach for fixing things (even though it worked!), I took away from it an important realization: the scope of possible causes of a weird, randomly-occuring problem is much larger than I'd normally assume. Over the years, I learned to identify some "outside context" things for computers - ESD, thermals, UV exposure, RF interference, voltage spikes in power lines, devices being almost but not quite connected. Because of that, when in a bind, "waving a dead chicken" may just be called for - in forms of e.g. percussive maintenance (hitting the thing with a wrench), moving things around, switching cables, disassembling, etc.
Re: Check if your IKEA chair is compatible with your screen
#168Remotely related, my screen makes a noise, somewhere between static and a whine, while displaying certain text files. Minimizing or closing the editor stops the noise, getting the text back on display restores the noise. I suppose it's some sort of resonance phenomenon.
sometimes when manipulating 3D CAD models, I can get a similar noise from my graphics card / monitor at certain orientations of the model sweeping back and forth as I rotate it I have a feeling that grey #A5A5A5 is row-hammering something
Re: Check if your IKEA chair is compatible with your screen
#169I've probably mentioned this story here, but my first job out of school was working for a nationally known cash register manufacturer, writing front-end software for the cashiers to use. This didn't happen to me but was told to me by an old-timer my first week there (mid-90s). A group had done an install at a grocery store. They did in-house testing of the new system, then rolled it out to 1 or 2 lanes to try it out…
Re: Check if your IKEA chair is compatible with your screen
#170you should NOT ground your chair directly, only ground it through a large resistor, 100K or so. (you might want to check that value, it's from memory, I think you want any potential electric "shock" to be down below the 1 milliAmp range) I'd use a ground strap designed for wearing while you handle MOSFET ICs. if you ground your chair directly, it is likely to make YOU be the best circuit to ground when you handle you…
Also prevents unexpected shocks to the buttocks upon sitting. Directly grounding shouldn't be particularly risky though. It's not uncommon to have a metal desk touching a grounded but not double-insulated chassis or dangling USB cable. And I get the impression that electrical systems are engineered so that users aren't touching live contacts when plugging things in - maybe less so in the case of US plugs. That said,…
if your chair is the path to ground, you, via your heart, are the path to ground