This could be a vibration between the steel bottom panel and the
transformer too. I'd suggest making sure "all" hardware is tight.
Mine doesn't humm at all. Line voltage is normally 123 VAC to 128 VAC.
73
Bob K4TAX
Eric Sluder wrote:
>
> Jerry & the rest of the list members:
>
> My line voltage here is 122.5 volts constant... I shall try your
> suggestion.
>
> I'm also going to try the re-tightening of the transformer, and other
> remedies as well.
>
> Thank you gent's for the tips. I'll post the results once I find the
> solution.
>
> 73,
>
> Eric
>
> ----- Original Message -----
> From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
> To: "Michael Melland" <w9wis@charter.net>
> Cc: "Eric Sluder" <kb9bgs@gte.net>; <tentec@contesting.com>
> Sent: Sunday, September 16, 2001 2:30 PM
> Subject: Re: [TenTec] Fw: Loud Hum w/Paragon I & 961
>
> > You might try lowering the line voltage to the power supply. Hum is a
> > sign of the core being run to saturation (cheap design short on core
> > area and copper). It should get very much quieter with only a small
> > reduction in line voltage from either a variac or a bucking transformer.
> > You can lower the line voltage until the power supply regulators loose
> > regulation on current peaks (key down CW) and then raise it a hair. Many
> > utilities tend to run line voltage higher than 117 so that the 10%
> > change from no load to full load that can come from two transformer
> > drops after last regulating the sub transmission voltage still will keep
> > a minimum voltage as generally required by state utility board
> > regulations. Running lower line voltage into the supply will let the
> > supply operate cooler and more efficiently.
> >
> > 73, Jerry, K0CQ
> >
>
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