strange buzzing noise

Discussion in 'Apple Collectors' started by 128kmacintosh, May 20, 2014.

  1. 128kmacintosh macrumors member

    Joined:
    May 20, 2014
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    USA
    #1
    So I bought this 128k macintosh, it makes a strange buzzing noise. Does anyone have an idea what it could be? sounds like a transformer, of how it would soound when someone gets an electric shock in cartoons... buzzzz.
     
  2. HunterCupp macrumors regular

    HunterCupp

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    Feb 13, 2014
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    Circleville, OH
    #2
    128kmacintosh

    Does everything else other than that seem normal? I.E; No screen flickering when turned on.

    -Hunter
     
  3. 128kmacintosh thread starter macrumors member

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    #3
    Hello Hunter
    Speaking of not normal... Do you know what this is???
     

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  4. MacTech68, May 20, 2014
    Last edited: May 20, 2014

    MacTech68 macrumors 68000

    MacTech68

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    #4
    My first thought was an AC mains voltage fan. But looking at the shape of the device, I can't be certain - it looks very odd.

    It seems to be held to the chassis with double sided tape. You'd need to take careful note of which diodes the clips are attached to before removing it.

    I'm really intrigued. :eek: I've seen secondary power supplies for hard drives added this way, but that box looks too small to be a power supply.

    It may be half of something that was mounted on the top of the floppy drive frame - you can see velcro there.

    EDIT: WARNING - further thought makes me wonder if the box is a crude 240v to 120v step-down transformer. Your power/sweep board seems to be a 120v only model. If your mains voltage is 220/240V AC, proceed with caution - removing the box could mean that running the machine on 220v or 240v will damage it.
     
  5. 128kmacintosh thread starter macrumors member

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    #5
    My thought was that it could be some odd fan.
    I'll leave it in place until I know what it was for.

    I am in the US, I'll update my profile . Im sorry
     
  6. MacTech68, May 20, 2014
    Last edited: May 20, 2014

    MacTech68 macrumors 68000

    MacTech68

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    #6
    Ok, in that case, it shouldn't be a step-down. If it is a fan, it's a very odd design.

    It certainly could be the case of the noise, though there are certainly other possible causes for such a noise.

    Can you get any more pictures (with slightly more lighting) of the item and the end of the clips? Are there any cables other than the two with the clips that come out of the box?

    EDIT: I notice now that your machine has an upgrade daughterboard attached to the motherboard - I can see nylon screws securing the two together. It appears to also have a SCSI upgrade on that card. Maybe it IS a small power supply for a Hard Drive or just extra power for the upgrade.
     
  7. 128kmacintosh, May 20, 2014
    Last edited: May 20, 2014

    128kmacintosh thread starter macrumors member

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    #7
    Looks like the unit itself is a so called monster mac made by levco, which had a 2 meg board.
    The Weird piece seems to be a 'Piezo cooling fan' , I've never seen anything like it before :D
     

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  8. MacTech68 macrumors 68000

    MacTech68

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    #8
    Thanks for that. I've never heard of these. It seems the two white blades will vibrate/flap at the mains cycle frequency (60hz for you).

    I do wonder how much use it really is. :confused:
     
  9. 128kmacintosh, May 20, 2014
    Last edited: May 20, 2014

    128kmacintosh thread starter macrumors member

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    #9
    I am trying to find more info on the 'monster mac' seems like there is a connector for a hard disk?
    How much are they worth?
    I attached a photo of the motherboard
     

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  10. MacTech68, May 20, 2014
    Last edited: May 20, 2014

    MacTech68 macrumors 68000

    MacTech68

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    #10
    From what I know, there was a second card that plugged onto the 2MB upgrade board to provide a SCSI port. It seems you may already have that as seen by the gray flat ribbon cable with the red stripe. IIRC this gives you SCSI for an EXTERNAL drive.

    As for value, it's an after-market, third party upgrade. Just how much they're worth I really couldn't say.

    It seems the board is a permanent fixture too. IE, you can remove it, but the motherboard will be non-functional.

    EDIT: This looks like a later board, but the SCSI port is certainly already present.
     
  11. 128kmacintosh thread starter macrumors member

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    #11
    Looks like this thing was state of the art in 1984 :)
    thank you for all your info.
    I tried to call the company , but the number is disconnected, no surprise :D
     
  12. briannaharbor macrumors member

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    May 22, 2014
    #12
    It could just be that you are operating on a dinosaur, and dinosaurs like to hum...other than that I dont really know.
     
  13. 128kmacintosh thread starter macrumors member

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  14. MacTech68 macrumors 68000

    MacTech68

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    #14
    Interesting little device. Thanks for posting the video.

    I now suspect that the buzzing MAY have been a cable sitting against one of the vibrating piezo fan blades.
     
  15. 128kmacintosh thread starter macrumors member

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    #15
    OMG I found out what the noise was. In the photo's you can see a label, It was lose and fell off. When it was gone the buzzing stopped , so I think it was the label vibrating
     
  16. tdiaz macrumors 6502

    Joined:
    Feb 7, 2006
    #16
    That would be it. The sticker buzzing. The point with those piezo fans was quiet, and it just kept enough air moving around to do the job.
     

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