Constant but irregular hissing noise - not the fan - FSP300-60THA

[SuperDuty]

Hi,

Yesterday I've changed my main computer case and decided to change the fan of my backup Fortron PSU, since it was making a slightly annoying hissing noise since I've installed it. Actually, when I got this PSU, the original fan was clogged and dirty so I've never used it with the original one.
But after swapping the fan AND the temp control unit from another identical power supply, the problem isn't solved...when I stop the fan, the noise is still there.
It's not a regular noise, but its constant at idle. Scrolling in Firefox will change the hissing. The noise goes away at higher loads (any game, or any heavy app). It scares me a bit now since I've used this PSU with this noise for about two months without any problem...


It's full of Teapo and OST in there, but I did not see any buldged cap.

[shovenose]

Re: Constant but irregular hissing noise - not the fan - FSP300-60THA

I've got an old 250w FSP that does something similar and I'd be interested to see if there is a resolution to this.

[c_hegge]

Re: Constant but irregular hissing noise - not the fan - FSP300-60THA

Most likely the caps are going bad. Teapo and OST (especially the latter), are both notorious for failing with no visible signs. Most if not all FSPs this age have bad teapos and/or OSTs

[ben7]

Re: Constant but irregular hissing noise - not the fan - FSP300-60THA

A few things that might be the problem:

1. Loose inductor wires/core
2. Bad caps
3. Unstable control loop (usually caused by bad caps!)

Hmm, this reminds me that my laptops psu squeals a bit when unloaded, but I think its just from hiccup mode.

First thing I would do is recap, Teapooos and Osts can be unpredictable.

[b700029]

Re: Constant but irregular hissing noise - not the fan - FSP300-60THA

The hissing could be coming from the CPU vcore regulators, not the PSU. It just so happens that the two are close together inside a regular PC case.