[Boatanchors] DRAKE TR-3

[Paul Kraemer]

Don't overlook the de-coupling electrolytic filter cap in the mic pre-amp 
and vox circuit
It will also cause the vox to hang partially closed
Paul K0UYA
----- Original Message ----- 
From: "David Stinson" <arc5 at ix.netcom.com>
To: <boatanchors at mailman.qth.net>
Sent: Sunday, November 22, 2009 3:37 PM
Subject: Re: [Boatanchors] DRAKE TR-3


> Both the TR-3 and TR-4 have a "vox" tube,
> 6EV7, I think... dual triode (forgive me, it's been
> a lot of years).  It gets leaky and does all kinds of
> wierd things.  The PTT relay winding is in the plate circuit
> of one of them.  Could be just slightly pulling the relay.
> If you let it go, the rig starts "hanging"
> when you let go of the PTT.
> Eventually it will start keying itself.
> And if you still don't change it, you'll come home to
> a shack full of smoke from fried finals.  Voice of
> experiance.  A lot of TR-3/-4 PTT relays have been changed
> when this tube was the real villian.  Get a new one,
> even if yours checks "good."
>
> ----- Original Message ----- 
> From: "AD5VJ Bob" <rtnmi at sbcglobal.net>
> To: <boatanchors at mailman.qth.net>
> Sent: Sunday, November 22, 2009 2:54 PM
> Subject: [Boatanchors] DRAKE TR-3
>
>
>>I am in the middle of restoring a Drake TR-3 and so far everything is 
>>going
>>well.
>>
>> However, I have a question:
>>
>> I have her receiving a cw signal right now on 14.025 or so, but the
>> speaker volume seems low and the S needle is sitting at 20 over
>> nine in rx mode.
>>
>> I cleaned the tube sockets with WD-40 and the wafer switches, but it
>> didn't change anything.
>>
>> I am guessing I may have an AGC tube starting to go south, but dont have 
>> a
>> tube checker to be able to tell.
>>
>> I also have around a .05 reading steady reading on the plate current 
>> meter
>> when it is in rx mode.
>
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