[TenTec] Fw: Loud Hum w/Paragon I & 961

[Eric Sluder]

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
>