Thread: AM radio noise
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Old July 23rd 03, 03:36 PM
w_tom
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Common problem when that computer expert selected a power
supply based upon price rather than on technical specs. Power
supplies must have an in-line filter. But many important
functions are forgotten to sell power supplies at less than
$80. Missing functions when a power supply is not provided
with a long list of specifications including:
PFC harmonics compliance: EN61000-3-2 + A1 + A2
EMI/RFI compliance: CE, CISPR22 & FCC part 15 class B

Where does that surge protector even cite numbers for noise
reduction? It remains inert - does nothing - until voltages
above 300 volts are observed. But then even that number is
often in small print. Again, if no specifications, then why
would you assume something will work only based upon an
arbitrary comment (such as high frequency capacitor). Once
numbers are provided, then surge protector does not even claim
to address your problem.

First confirm the power supply claims to provide a long list
of essential functions, or replace it. Cheap power supplies
can even contribute to damage of other computer components.

Randy wrote:
I've had this problem awhile but it seemed to be getting worse. My
computer pretty much wipes out my AM radio (FM unaffected). All the
wall sockets in my room are on the same circuit so I'm out of luck
moving the radio. Now... I expect the AM radio to go bonkers if the
system is on but this happens when the computer is off too. If I
switch the power supply to off in the back of the case all is well. Is
this normal?

The graphics board always has a light on (Radian 9600 pro) for the 8x
agp but I wouldn't think this would have that kind of affect. I hooked
the computer up to a belkin surgemaster with a high frequency
capacitor to no avail. I hooked my AM radio to the same surge
protector and again zippo.

Could the power supply be the culprit? If so are there ones on the
market anyone could recommend that wouldn't contaminate the AC line of
the house?