[R-390] R-390 RF Gain Control

[Steve Toth]

Good call - I have done this in repairing an automobile radio from the sixties.  It works.
- Steve  W7SJT

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    On Sunday, September 12, 2021, 03:27:08 PM MDT, David Wise <david_wise at phoenix.com> wrote:  
 
 I seem to recall that a fixed resistor from linear wiper to one end can approximate a log taper, probably well enough for this application.

Dave Wise

From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Roy Morgan
Sent: Sunday, September 12, 2021 8:08 AM
To: Kevin Schuchmann
Cc: R-390 at mailman.qth.net
Subject: Re: [R-390] R-390 RF Gain Control

To the creative among us,

Some clever person among us likely can design a replacement circuit to function well as the hard to find reverse log taper original gain pots.

Maybe a pot with the right resistance curve but lower dissipation rating combined with a FET or opto-isolator.

Roy Morgan
Custodian of more than one R-39x radio.
K1LKY Western Mass

> On Sep 12, 2021, at 1:11 AM, Kevin Schuchmann via R-390 <r-390 at mailman.qth.net> wrote:
>
> Hi All,
>
> Hunting around I found this on Ebay and I have ordered one. https://www.ebay.com/itm/164923700436<https://www.ebay.com/itm/164923700436>
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