Quiet Down PC Power Supply--Not a Fan Problem

  • Thread starter Thread starter RD
  • Start date Start date
R

RD

I have an Enlight 350W power supply that has been doing a fine job for
several years. In fact, it is still doing a good job but has recently
developed a high-pitched whining noise. It is not the cooling fan. I opened
up the supply, and the noise seems to eminate from a section containing some
good-sized toroidal transformers. There are a couple of power transistors on
large heat sinks nearby as well, so I don't know which component is the
noise source. Anyone have any ideas on how to repair this problem? I was
thinking of squirting a bunch of high temp silicone all over the components,
but thought that might not be good because it might cause the components to
heat up too much. I have a new ps on the way, but would be interested in
hearing theories on how to fix this one.

RD
 
RD said:
I have an Enlight 350W power supply that has been doing a fine job for
several years. In fact, it is still doing a good job but has recently
developed a high-pitched whining noise. It is not the cooling fan. I opened
up the supply, and the noise seems to eminate from a section containing some
good-sized toroidal transformers. There are a couple of power transistors on
large heat sinks nearby as well, so I don't know which component is the
noise source. Anyone have any ideas on how to repair this problem? I was
thinking of squirting a bunch of high temp silicone all over the components,
but thought that might not be good because it might cause the components to
heat up too much. I have a new ps on the way, but would be interested in
hearing theories on how to fix this one.
Click to expand...

Decaying electrolytic capacitors can cause that by making the
switching regulator compensate for low voltage by increasing the duty
cycle too much or by causing the switching transistors to turn and off
too slowly. Those capacitors may be bulging or leaking on top (don't
mistake glue for leakage), or they could look normal but still be
bad. It's also common for coils and transformers to vibrate audibly,
and silicone rubber (not grease) can quiet them down, but varnish may
be better if the coil or transformer has fine windings or deep
crevices in layers of paper.
 
In fact, it is still doing a good job but has recently developed a high-pitched
whining noise. It is not the cooling fan. I opened up the supply, and the
noise seems to eminate from a section containing some good-sized
toroidal transformers. There are a couple of power transistors on large
heat sinks nearby as well, so I don't know which component is the
noise source. Anyone have any ideas on how to repair this problem?
Click to expand...

After winding the torroid, we would put it into a vacuum, then bath
it is varnish. The varnish would be sucked into the coils so they did
not vibrate. To stop the vibration, you must do something equivlalent
deep inside the windings. IOW live with it. As usual, most failures
are manufacturing defects.
 
Back
Top