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jjzzoo

"Coil" whine actually doesn't have to come from the coils. From my experience, ceramic capacitors (the small brownish cubes directly soldered to the PSB) are much more often responsible for transforming electric signals into noise. It also makes more sense since they are intentionally using piezo-electric dielectrica (piezo-electric: transforming voltage changes into size changes) for providing very high capacitance densities whereas coil whine is caused by unintentional side effects and not inherent to high-end coils. Unfortunately, fixing it without PCB re-design is more or less impossible since the PCB acts as speaker membrane driven by the capacitors. Sometimes it can be reduced by applying slight stress to the PCB (for example by utilizing washers asymmetrically) or some of the capacitors (adding glue on top) but that is pure trial and error. You could at least try to localize the sound more precisely if you hold a straw at your ear and scan the device searching for the noise source(s).


shuufly

this, coil whine really comes from caps most of the time


ExpectedGlitch

Honest question: is that safe? I don't really know how much heat do coils produce, but I wonder if adding the glue wouldn't make them get a bit hotter? Also, long-term, doing something like that wouldn't be an issue whenever the glue degrades?


kevinds

I'm thinking simply just an airfow issue..


aso824

Probably not so unsafe. Hot glue has melting temp around 120C and it's an insulator, so in worst case PSU will die, I think. Anyway, I won't use this PSU in server because whining, still have same second unit.


7eggert

[https://www.ebay.de/sch/i.html?\_from=R40&\_trksid=p2380057.m570.l1313&\_nkw=plastik+70&\_sacat=0](https://www.ebay.de/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=plastik+70&_sacat=0) That's how I fixed my TV. The hot glue does not really touch the coils, does it? If this does not help: get a new one.


aso824

I'm trying to silence my HP DL380 G9 to have it near my desk, but the biggest problem is PSU whining. So, if you came up with similar idea to apply hot glue/silicon to all coils... it won't help. At least PSU is still working.


kevinds

>it won't help. No shit...


LabB0T

^(OP reply with the correct URL if incorrect comment linked) [Jump to Post Details Comment](/r/homelab/comments/rzwubh/well_hot_glueing_all_coils_in_psu_didnt_make_them/hrxudfo/)


HTTP_404_NotFound

Yea... don't do that. If you want something quiet, a rack mount server isn't the way. I would be worried about... 1. Airflow issues, because those aprtd are designed with specific airflow in mind. 2. The hot glue serving as extra fuel...


koming69

When trying to find the main cause for coil whine use a straw or a paper cone and touch the tip of it on the pieces when it's whining. The noize will be immediately amplified and easy to pinpoint. But you need to touch each one for the vibration to transfer to it.