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RFI Hum Problem. PC inducing hum in stereo

Discussion in 'Hobby Electronics' started by John Leister, Nov 25, 2003.

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  1. John Leister

    John Leister Guest

    OK first off my pc still works, or else I'd not be writing this
    post.

    But the last two days I have not been able to use my stereo
    on the AM band due to a very noticeable hum in the background
    on the top of one particular station on the AM band.

    This occurs even when the computer is shut down but the moment
    I remove the power plug from the mains the hum vanishes.

    I'm thinking this is coming from the power supply inside the case.
     
  2. Mark Harriss

    Mark Harriss Guest


    Is you 'puter hooked up to your amplifier? it may be an
    earth loop. Also I think ATX style power supplies are always on
    even when the computer is shut down.
     
  3. your power supply is dying, dis-continue use and get a replacement - codegen
    power supplies are very quiet in the RF area. $55ish

    if yours is a cheaper power supply, the psu will kill the rest of the system
    when it goes (ritmo/sato power supplies are notorious for this)
     
  4. John Leister

    John Leister Guest



    It's an ATX power supply
     
  5. Rod Speed

    Rod Speed Guest

    Bugger.

    More work required on that usenet deliverable imploder.
    Thats just coz the stupid children 'running'
    that station are having a hum-in, stupid.
    Then you should obviously leave it unplugged, stupid.
    Yep, the power supply is still operating even with the PC
    turned off, so it can see you press the power button etc.
     
  6. Rod Speed

    Rod Speed Guest

    More bullshit.
    More bullshit.
     
  7. Ken Taylor

    Ken Taylor Guest

    John, did you change anything at all in the last few days? cabling, position
    of devices, etc??

    Ken
     
  8. "But the last two days I have not been able to use my stereo
    on the AM band due to a very noticeable hum in the background
    on the top of one particular station on the AM band"

    i.e it's just starting to occur

    i fix PC's for a living and i have the after effects of many sato/ritmo
    power supplies failing taking the rest of the system with it (except the
    floppy drive in one case)
    over voltage protection on the output lines either failed or were
    non-existant in these supplies, i have 10 in a stack that have 'just failed'
    they all have things in common - one being an increase in interference to an
    am radio (which i always have on for this very reason - that and theres
    better programming on am)

    I doubt you can back that claim up.
    i have a stack of these that failed 3 with undersides of the psu's BLACK, 4
    just not running with chard areas around a zener diode and the other 3 had
    other issues like tap it and the pc would reset AND THATS JUST THIS YEAR -
    sounds like quality to me :)your full of shit your self - you say shit like 'total crap' 'absolute
    bullshit' etc but you never back up ur claims - maybe it is you who be full
    of da crap no?
     
  9. what brand / model is your PSU?
     
  10. Rod Speed

    Rod Speed Guest

    Got sweet **** all to do with your stupid pig ignorant
    claim that thats because the power supply is dying
    and is about to kill everything powered from it.
    You actually con people into paying you to pig ignorantly
    thrash around and **** their systems quite a bit of the time.
    Bet thats a lie on that 'many' claim.
    Another lie on that last bit.
    Whoopy fucking do. Power supplys fail, stupid.
    Got sweet **** all to do with your stupid pig ignorant claim that
    that interference is guaranteed to be an indication that the power
    supply is about to fail and take everything powered from it with it.
    More fool you. You can grovel towards mecca too if
    you want, proves sweet **** all about anything at all.
    Pathetic, really.
    YOU made that stupid pig ignorant claim.

    YOU get to back up that stupid pig ignorant claim.

    THATS how it works.
    Thats an entirely separate issue to your stupid pig ignorant
    claim that am interference guarantees that its about to fail
    catestrophically and kill everything powered from it, and
    that ritmo/sato power supplys are notorious for doing that.

    Anyone with a clue knows that power supplys die, fool.
    Whoopy fucking do. 10 failed power supplys is sweet **** all.
    Separate issue entirely to your stupid pig ignorant claim.

    Reams of your puerile shit any 3 year old could
    leave for dead flushed where it belongs, child.
     
  11. Mainlander

    Mainlander Guest

    ATX is not a brand
     
  12. Mainlander

    Mainlander Guest

    He is, he used to post the same rubbish in aus.aviation
     
  13. Peter Lowrie

    Peter Lowrie Guest

    You have an earth problem - probably floating. Either disconnect the
    sheilding/earth on the cable to the stereo so only the signal wires are
    connected or place a 101 to 104 MKT capacitor in series on the earth

    ____________||___________ Earth sheild with capacitor
    _________________________ Left sig
    _________________________ Right sig

    :) Peter Lowrie
     
  14. John Leister

    John Leister Guest



    I don't know the brand the case was a generic no brand
    case which came with the power supply.

    As a precaution I am purchasing a brand new one just to
    be on the safe side.
     
  15. John Leister

    John Leister Guest



    No No change in card layout, wiring or anything added or removed.


    I am purchasing a second brand new power supply in the hopes it
    will fix the problem.
     
  16. problem with switchmode power supplies, is they are so relient on many
    things in the psu circuit to be correct or else theres a risk of sending
    excessive voltage down the line to the devices at the end, believe me, i
    have literally seen this happen in front of me,

    plug system in, turn it on zzzz zzz zzz - then there was that smell of
    electronic smoke, and the PSU had failed passing huge amounts of voltages
    down the lines burning holes in the chips of most of the add-on cards,
    frying the cdrom, hard disk, killing the ram, cpu and motherboard. this
    system had ONLY the floppy drive still OK. - the over voltage protection
    section of the power supply had either failed or didn't exist, this was a
    sato/ritmo power supply.

    no other systems in the shop experienced any problem at the time this
    happened, no light dimming etc.

    I found alot of near dead power supplies would cause interference with the
    radio (which i always have on AM for this reason) in a different way to what
    i normally experience, like the interference would warble in frequency beat
    or pulse, and would sound un-controlled.

    dunno bout you, but i loose trust in things when there protection messures
    don't function.

    the ones i use at the shop either fail upon turn on (one has done this) or
    keep working for a long time, and the best bit is the 3 year warranty from
    the supplyer.
     
  17. John Leister

    John Leister Guest

    Well I did say I am buying a new one to replace the existing one.

    What more can you do besides that?
     
  18. Rod Speed

    Rod Speed Guest

    There may be a brand on the power supply box itself.

    You may need to take the power supply
    out of the case to be able to see the label.
    He's got his head completely up his arse on that.
     
  19. Rod Speed

    Rod Speed Guest

    Mindless pig ignorant bullshit. A properly designed power
    supply has a completely separate mechanism to shut down
    the supply on overvoltage on any of the rails due to failure.
    Separate issue entirely to your stupid pig ignorant claim that JUST AM
    INTERFERENCE ON A PARTICULAR RADIO STATION INDICATES
    THAT THE POWER SUPPLY IS ABOUT TO DIE LIKE THAT.
    And you're so pig ignorant that you cant even
    work out if the over voltage protection is there
    in that supply, or whether it didnt work properly.
    Proves sweet **** all about anything at all. That result
    was also seen with some of the Macase power supplys.
    You're presumably so pig ignorant that you dont even
    recognise the brand, but it once had the same
    reputation that antech does currently.
    You can certainly see a problem with a supply
    thats arcing internally like that, BUT IT DOES NOT
    INTERFERE WITH JUST ONE AM RADIO STATION.
    Most likely the chopper freq is varying.
    Better get used to that, child. Its a fact of life.

    Even someone as stupid as you must have
    noticed the situation where a fuse doesnt save
    what its fusing, particularly with a mains surge.
    Just like with the absolute vast bulk of power supplys, stupid.
    Pointless with the failure rate so low.
     
  20. OH DER - sould i underline 'properly built'?
    OH DER - never said JUST ONE STATION >
    SOME? SOME? you forget i mentioned SATO/RITMO?
    WITH Ass fuckers like you around, no thanks
    OH DER - Except the cheap made ones that fall out of specification
    SATOs Failure rate is HIGH
     
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