[Johnson] BA transformer replacements

Mon, 4 Feb 2002 12:59:14 -0800

Hi John. Why not use a bucking transformer. i use one in line for all of my
tube gear. 20 amp filament transformer does the job. the line voltage works
out to be between 108 and 110 volts.   73 Rick VE7RiK
----- Original Message -----
From: "Dr. John Harden" <[email protected]>
To: <[email protected]>
Sent: Monday, February 04, 2002 12:20 PM
Subject: [Johnson] BA transformer replacements


> Whenever I have a transformer fail I look at a new one by Stancor, etc.
> If  I can't find a replacement I use Peter Dahl. They are expensive but
> extremely dependable. Old transformers usually break down and I avoid
> them.
>
> When the first Collins 516F-2 power supplies came out the primary was
> only 108 VAC!!!! The primary voltage went up over the years as Collins
> was aware of the increase in AC line voltages to 120 VAC or more.
>
> I recently restored a 516F-2 supply for use with my KWM-2A transceiver.
> I use high-quality solid state replacements for the 5U4 and 5R4 that I
> purchased locally at Ack Radio Supply. Naturally I use a variac
> auto-transformer to set the AC. With only
> 103 VAC on the primary I get the rated 285 VDC and the 800 VDC out of
> the supply key up.....Imagine where it would be with 120 VAC or more on
> the primary!!!! Old transformers will quickly break down if the input AC
> is too high...
>
> 73,
>
> John, W4NU
> Atlanta
>
>
>
>
>
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