Buzzing sound from switching PSU's?

Hi. Sorry for the crosspostings

I've recently noticed a noise coming from one of those small fluorescent (sp?)
lamps, that sounds like a high-frequency (~1KHz) buzzing. As I understand,
fluorescent lights use SMPS (switching) power supplies.

This buzzing sometimes also happens in my PC PSU (I've discarded fan noise) and
in the monitor (from the Flyback, it seems).

The buzzing is barely noticeable but gets noticeable when monitor + lamp + CPU
is on :/

Q: Is a little buzzing sound coming from SMPS, means any problem? The
lamp/monitor/CPU work normally, so the SMPS is not problem.

I've readed that it's from either the SMPS controller (???) or the magnetics.

Thanks.
--
Chaos Master®, posting from Brazil. REPLY TO GROUP!
MSN: wizard_of_yendor[@]hotmail[.]com http://marreka.no-ip.com
"You're guilty; the punishment is death for all who live."
-- Iron Maiden, "Out Of The Silent Planet"

Hi!

Q: Is a little buzzing sound coming from SMPS, means any problem? The
lamp/monitor/CPU work normally, so the SMPS is not problem.

Generally speaking, no. It usually indicates a supply that may be a little
cheap or undersized to the load its carrying. For older supplies it might
indicate a minor problem getting ready to occur, but generally you don't
have to worry about it.

William

William R. Walsh, William R. Walsh, William R. Walsh.... did you really write
this article (K3YQc.101412$eM2.33315@attbi_s51) in newsgroup
(sci.electronics.repair) at the date of (Sat, 07 Aug 2004 03:32:58 GMT)?
Hi!

Q: Is a little buzzing sound coming from SMPS, means any problem? The
lamp/monitor/CPU work normally, so the SMPS is not problem.

Generally speaking, no. It usually indicates a supply that may be a little
cheap or undersized to the load its carrying. For older supplies it might
indicate a minor problem getting ready to occur, but generally you don't
have to worry about it.

So good. It's because my PC PSU is old (AT PSU for a 200MHz Pentium), and the
fluorescent lamp is of an 'unknown' brand (the lamp was very cheap).

[]s
--
Chaos Master®, posting from Brazil. REPLY TO GROUP!
MSN: wizard_of_yendor[@]hotmail[.]com http://marreka.no-ip.com
"You're guilty; the punishment is death for all who live."
-- Iron Maiden, "Out Of The Silent Planet"

Dunny Rummy wrote:

Get a Antec 550 true power PSU and never worry again

The OP wrote:

AT PSU for a 200MHz Pentium

O K ;-)


On Sat, 7 Aug 2004 00:49:04 -0300, Chaos Master
wrote:


William R. Walsh, William R. Walsh, William R. Walsh.... did you really write
this article (K3YQc.101412$eM2.33315@attbi_s51) in newsgroup
(sci.electronics.repair) at the date of (Sat, 07 Aug 2004 03:32:58 GMT)?

Hi!


Q: Is a little buzzing sound coming from SMPS, means any problem? The
lamp/monitor/CPU work normally, so the SMPS is not problem.

Generally speaking, no. It usually indicates a supply that may be a little
cheap or undersized to the load its carrying. For older supplies it might
indicate a minor problem getting ready to occur, but generally you don't
have to worry about it.

So good. It's because my PC PSU is old (AT PSU for a 200MHz Pentium), and the
fluorescent lamp is of an 'unknown' brand (the lamp was very cheap).

[]s

Dunny Rummy, Dunny Rummy, Dunny Rummy.... did you really write this article
) in newsgroup
(sci.electronics.repair) at the date of (Sat, 07 Aug 2004 04:51:07 GMT)?
Get a Antec 550 true power PSU and never worry again

1. AT PSU
2. I don't need 550W as I am not into CPU overclocking nor do I need a 'high
power' video card. 350W or so is enough for me


[]s
--
Chaos Master®, posting from Brazil. REPLY TO GROUP!
MSN: wizard_of_yendor[@]hotmail[.]com http://marreka.no-ip.com
"You're guilty; the punishment is death for all who live."
-- Iron Maiden, "Out Of The Silent Planet"