[Drake] Drake AC3 and AC4 power supplies

[Ron]

John,
One other thing you will find on the AC3s, is a little shorting test point.  When you take that jumper off of ground, you have a 10 ohm (if I recall correctly) resistor in series with the plate supply, on the ground side of the supply.  It is then possible to use the voltage developed across that resistor as a direct measure of the idle current.  You can then adjust the bias supply variable resistor with much more accuracy and ease.  Look in the TR3 manual and it explains the test point as well as gives schematic for the AC3.

73,
Ron WD8SBB

> 
> Message: 2
> Date: Mon, 28 Nov 2011 20:13:17 -0600
> From: richard radke <rar100 at excite.com>
> Subject: Re: [Drake] Drake AC3 and AC4 power supplies
> To: John King <k5pgw at yahoo.com>
> Cc: Drake at mailman.qth.net
> Message-ID: <5AD3A938-8726-4F86-9CC7-BEE7CCE7C886 at excite.com>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes;
> format=flowed
> 
> John,
> 
> The AC-3 is open frame and came (built for the TR-3) out
> before the  
> AC-4 and it's enclosed...They're interchangeable among
> the  
> rigs...Everything works with everything...Someone was
> thinking back  
> in the day...You could upgrade a piece at a time
> 
> Rick
> W9WS
> 
> 
> 
> On Nov 28, 2011, at 6:29 PM, John King wrote:
> 
> > I have several AC4 power supplies and recently
> acquired two AC3  
> > power supplies.
> >
> > What are the major differences between the AC3 and
> AC4.
> >
> > Were they made for different models of Drakes? If so
> which power  
> > supply for which radio?
> >
> > Thanks for the information. 73, John, K5PGW
> >
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> 
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> End of Drake Digest, Vol 94, Issue 10
> *************************************
>