Transformer whine on Viewsonic VA912b

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  • Jmf1320
    New Member
    • Mar 2011
    • 4

    #1

    Transformer whine on Viewsonic VA912b

    Hello Experts,

    I have been scouring the forums for a solution to this problem, but I think some advice would be good before I take action.

    I have recapped 4 Viewsonic computer monitors successfully this week (my first foray into this field), but one of them is whining or buzzing at a high pitch. I've narrowed it down to what I think is a transformer noted in the attached pictures. I don't know if it was present before I repaired it. The whine is only present during active operation, not during standby, and it doesn't lessen over time.

    I replaced all of the caps. At the electronics store, an employee said I should be okay replacing 2 1000uf 25v caps with 1200uf 35v caps, which I did. Could cause the problem? They are Nichicon HE(M) caps.

    I saw lots of suggestions to dip the transformer in lacquer. Is this to stop mechanical vibrations in the unit? Is there a certain type of lacquer which is best?

    I have already learned quite a bit reading here. It's great to have a community of people like this willing to help out. Thanks!
    Attached Files

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