Converted server psu's

[sureshot]

I have a bit of a hobby going on converting old server power supplys, my use of these is mainly for cb radio. What I've noted with a few is electrical noise when connected up to the radio, some units are fine and are clean enough on there output for use, others are just to noisy.

An example is the hp 1200 dps unit, it gives a fairly large noise component when connected up to cb radio. So my question is this, does anyone have a filter circuit that can be built as an external add on to clean up the output, a schematic maybe for a wide frequency filter to clean up this noise. I don't have the use of a scope, so it makes it a bit tricky, although a suspect the fan pwm to be the noise culprit, although that's speculation on my part.

Thanks for reading, any help appreciated.

 

[Harald Kapp]

Try a standard mains filter (here's an example). These are built to suppress radio interference on mains and should be suitable for your application, too (from a bandwidth perspective). You'll have to observe the current rating!

 

[sureshot]

Thanks Harald for your help, I will give this company a call and see how much one of these emi filters would be. Thanks again for the link.

 

[Harald Kapp]

I will give this company a call

You'll probably not be able to buy directly from the company. Try the usual suspects (Mouser, Farnell etc.). This kind of filter is usually on stock.

 

[sureshot]

I will have a look round these suppliers, thanks Harald.