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MC275 Hum Conundrum

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rkic

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Joined 2004
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I replaced most of the caps in my MC275. Power up test revealed a loud hum. Making sure of my wiring I chanced to approach capacitors C1 and C12 with a pair of needle nose pliers - the hum got substantially louder perhaps 6 - 9 db or so. An aluminum framed magnifying glass also increased the hum. A plastic pen did not.

What do you think?

Thanks in advance and Happy Fourth.
 
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