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Gli ultimi otto messaggi ricevuti dalla Federazione
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@dentangle I like ventricina but this is a locally produced salami and it's perfect on pizza. I don't know how they call it, anyway
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Servizi pubblici, tutte le sinergie fra PagoPa e comuni
L'articolo proviene da #StartMag e viene ricondiviso sulla comunità Lemmy @informatica
Che cosa è emerso durante il workshop “Innovazioni e sviluppi nell’ecosistema PagoPA. Dal welfare alle notifiche: sfide e soluzioni startmag.it/innovazione/serviz…
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Mettiamoci anche quelli di Open.
https://www.open.online/2025/11/15/ucraina-corruzione-volodymyr-zelensky-timur-mindich/
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@marino222 il sintomo è un mistero per chi non sa ascoltare.
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Using the Pyroelectric Effect to Identify Broken MLCC Capacitors
Vintage computer hardware can fail in a variety of fascinating ways, with [Bits und Bolts] dealing with an interesting failure mode, in the form of degraded MLCC capacitors on Voodoo 2 graphics cards. These little marvels of miniaturized surface-mount technology enable the placement of ceramic capacitors with very little space required, but as they degrade over time or due to physical damage, they can cause big issues in a circuit.
In the case of the two Voodoo 2 GPUs that [Bits und Bolts] was trying to fix, the clue that something was wrong was graphical glitches, which seemed to be related to something dragging down the 5V rail. Using the standard ‘inject voltage and see what gets hot’ method, he discovered a couple of dead MLCCs and replaced them. But something was still dragging the rail down. Unfortunately, whatever it was wasn’t enough to heat up the part in question, and no sane person wants to desolder hundreds or even thousands of MLCCs on a PCB and see whether it makes a difference.
Ultimately, the pyroelectric effect was used to hunt down the culprit, saving countless hours of work. This is a property of certain naturally electrically polarized crystals, in which the material generates a voltage when heated or cooled. Materials like that used in MLCCs, for example.
With a hot air gun set to 200 °C and aimed at a specific MLCC, it was possible to measure changes not only in resistivity but also in voltage between the 5V rail and ground. The voltage spike was relatively minor for the smaller MLCCs, but the larger ones showed a significant voltage swing of around 2.5mV.
The culprit turned out to be a large MLCC, which showed only a weak pyroelectric effect and a resistivity that didn’t drop as quickly as that of similar MLCCs on the same board. After replacement, the faulty MLCC did indeed measure as faulty, and the card’s 5V rail now showed a healthy resistance level to ground.
In addition to knowing what kind of resistivity you should measure on a PCB’s voltage rails relative to ground, this method provides a fairly painless way to quickly find a dodgy MLCC. Just make sure not to try this method on electrolytic or tantalum. Heating those up won’t go well.
We often treat decoupling capacitors as more art than science, but of course, we shouldn’t. MLCCs can even exhibit the piezoelectric effect, too.
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@miles mi mandi una foto dell'insieme per vedere qual è? anche se alla fine montano tutti la stessa roba
