From: Garey Barrell 
Subject: Re: [drakelist] B line Help Please]



Tim -

That's what I get for being in a hurry......

The Bias supply filter cap in the AC-4 (C5a and b) is the possibility after the 
6EV7.  Early units used 20 uF, later used 40 uF.  Easy to check by just 
paralleling the output (C5b) with whatever you happen to have around that is 
more than 20 uF.  Watch the polarity!  Typically hanging after a transmission is 
tube related.  A filter cap failure usually presents as a go/no-go when you set 
the GAIN or VOX SENS control.  Either keyed or not!

 > The relay hanging is probably a gassy 6EV7.

73, Garey - K4OAH
Atlanta

Tim English wrote:

> Have a few problems with my B line I am hoping I can't get some answers 
> to here.
>  
> 1. On my T4XB, you set the relay delay for a resonable delay time, then 
> after a long cw xmission the relay hangs and wont release until you turn 
> the delay pot way back. Then it wont key again until you run the delay 
> pot back up a ways. Doesn't seem to be a happy medium. Could this be a 
> problem with the 6EV7 VOX tube ?
>  
> 2. On my R4B, all cw signals sound like they have a slight ac ripple to 
> them and not a pure tone. The receiver seems sensitive enough just the 
> cw signals done sound clean. Also my calibrator is not working. Anything 
> I can check for on these items ?
>  
> --
> Tim, K8TJ
> (ex-WB8OGM)
>  
>  


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