[Drake] AC-4 voltage stability problem

Tue, 23 Dec 2003 18:20:01 -0600

Hi Pat,

Perhaps I wasn't quite clear on my description.  It's not a regulation
problem in the sense that on key down the level of voltage drops to a
specific value.  It's a rapid variation in the level of the voltage above
and below center.  It's not regular and it's not apparently related to the
expected ripple voltage.  It is very much as if there was a bad ground and
the level of DC was moving around at an erratic rate.

I am making the observations with my Tec. 453 scope and to insure that it's
not a problem within the scope itself, I've looked at other power supply
outputs and they are rock steady.  Though not as easy to see, I can see
variation of the voltage on my Fluke DVM as well.  The problem exhibits
itself with or without the connector plugged into the T-4XB transmitter.
Without it being connected to the transmitter, I've shorted the two pins
within the connector to turn the supply on.  The effect is the same.

Dan W. Dooley WB5TKA
 email: [email protected]
 http://www.dooleystreasurechest.com

----- Original Message ----- 
From: "Patrick A. Thompson Sr." <[email protected]>
To: "Dan W. Dooley" <[email protected]>; "Drake"
<[email protected]>
Sent: Tuesday, December 23, 2003 6:09 PM
Subject: RE: [Drake] AC-4 voltage stability problem

> Are you really concerned about a one volt change or is this a typo?
>
> For a one volt change in line voltage you could easily see 6 volts or more
> change on the 650 volt supply.  Regulation under load might allow a 50
volt
> drop or more on the 650 line and 20 or so on the 250 volt line. You may be
> seeing the line voltage variations multiplied by the voltage rise of the
HV
> transformer.
>
> It really doesn't look like a problem to me.
>
> Only the oscillator voltage was shunt regulated and then only with a gas
> tube.
>
> Perhaps the operational problems are due to another cause.
>
> Let the "group" know what the symptoms are and perhaps they have been
noted
> before.
>
> Pat
> wa4tuk
>