Hardrives that emit RFI....??

[GhostRider_71]

A friend of mine asked me to look at his computer. The problem was he could hear noise from his speakers. He said he noticed that the noise was in sync with the harddrive LED switching on and off...I said to my friend that the harddrive was possibly emitting radio frequency interference...

Has anyone heard of this..and if so what should i do to fix the problem...

I have changed the IDE(DMA) cable and still no luck...

[SingSing]

The hard drive draws more current when it is active, and the PC switching power supply trying to switch frequency/duty cycle to supply the juice.

In short, replug all the power connectors in the PC, and see what happened. If you recently added parts to the PC, you should replaced the PC power supply with a new and higher power unit.

[redwudz]

I would suspect bad shielding in the computer or poor grounding on the motherboard. Or, as mentioned, a problem with the power supply. Just about everything on the motherboard can emit RF, especially with the speeds computer buses and CPUs are operating at these days. I doubt it's the HD itself, more likely the PS or the IDE controller or some loose cabling. But check the screw holding in the HD also.

And you first might want to plug some headphones into the audio out of the computer instead of the speakers and make sure the problem is not with the speakers themselves. If the computer has a separate sound card, that could also be a suspect. Make sure it's fully seated in the PCI slot.

[piano632]

This actually happened to me a few days ago. Everytime the HDD was accessed, I'd hear a little pop or tick in the audio I was listening to. After much fussing around, I found it was simply that DMA was not enabled on both IDE channels for some reason (and it was using PIO mode). So make sure DMA is enabled for all HDD's and optical drives in the BIOS or just set to "Auto" detect.

[TBoneit]

It is most likely noise on the power bus in the computer that powers either the built-in sound or if equipped with one the sound card.

The hard drive uses both a 5 volt and a 12 volt supply and most likely is puting some sort of noise onto that supply bus which is also feeding the sound card. severasl options come to mind.

Try a different powwer supply that may have better filtering.
Try a different sound card.
Try a USB sound device such as USB headphones.
Try playing with the sound mixer settings. Turning off anything not needed. Example could be Microphone in, Line in.....Easy way to test this start a defrag so the hard disc is being accessed and then start playing with the mixer levels to see if you can isolate the problem.

Good Luck

Also the inexpensive speakers on our test bench seem to be sensative to Cell Phone usage. They get a buzzing kind of interference when a cell phone is in use close to them.

[Nelson37]

This used to be fairly common. It is possible some configuration changes will solve this.

However, I have had several PC's where this was resolved only by replacing the HD with a different one. Same model HD, no other changes, sound problem disappeared.

[GhostRider_71]

Thanks your for your replies...

Problem solved, I disabled onboard sound and installed a new pci sound card.
The noise has now dissapeared....

Once again thanks for your prompt replies...