Re: [Amps] 3-500ZG brands

[Pete Smith <n4zr@contesting.com>]

My repair was to the tube pins themselves.  You could clearly see where the 
solder had melted out from around the filament leads, so that they wee no 
longer making a good high current connection to the pins.  I just wrapped a 
wet rag around the pins whe4e they seal to the glass of the envelope, to 
keep that area cool, and used a 140-watt soldering gun. I also polished the 
pins with emery cloth, and did the same to the inside of the tube socket 
clips they mate with.

There are different sorts of silver solder, depending on the 
application.  You do not want the stuff used for plumbing, because its melt 
temp is too low.  The other stuff is expensive and you don't need very 
much, which is why I suggested Rich as a source.

73, Pete

At 10:45 AM 8/12/2004, you wrote:

> Thanks to everyone for the quick replies to my question.  I will check the
> tube, socket and soldering before concluding that the tube is bad.  I looked
> at the solder connections on the sockets and they definitely look like they
> could use resoldering.
>
> Pete, please describe the repair you made.  Was it to the socket or to the
> tube pin itself?
>
> I need to acquire some silver solder for some antenna projects and it sounds
> like it will be useful here as well.  Is silver solder readily available or
> is it usually a special order?  Does it require a special flux?
>
> Thanks,
> Clay
>
> ----- Original Message -----
> From: "Pete Smith" <n4zr@contesting.com>
> To: "Clay W7CE" <w7ce@curtiss.net>; <amps@contesting.com>
> Sent: Thursday, August 12, 2004 3:46 AM
> Subject: Re: [Amps] 3-500ZG brands
>
>
> > At 10:04 PM 8/11/2004, Clay  W7CE wrote:
> > >I've just acquired a Kenwood TL-922A which needs a new pair of finals
> (one
> > >of the filaments doesn't light up).  Does anyone have experience using
> the
> > >Taylor or RF Parts branded 3-500ZG tubes in this amp?  Does the cathode
> bias
> > >need to be changed when switching to the 3-500ZG?  Any recommendations
> will
> > >be appreciated.
> >
> >
> > Clay, before you do this, check to be sure that the filament hasn't simply
> > opened due to overheating of one of the filament pins.  This is a common
> > failure because the tube socket springs weaken with age and the resulting
> > resistance between the pin and the socket causes local heating.  I have
> > successfully repaired one that had gone this way with silver solder that
> > Rich Measures sold me (cheap), and have another awaiting the same
> treatment.
> >
> > 73, Pete N4ZR
> > The World HF Contest Station Database
> > was updated on August 2, 2004
> > 2753 contest stations at
> > www.pvrc.org/WCSD/WCSDsearch.htm
> >

73, Pete N4ZR
The World HF Contest Station Database
was updated on August 2, 2004
2753 contest stations at
www.pvrc.org/WCSD/WCSDsearch.htm  

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