[Amps] 3CV1500A7

[Mike Schatzberg]

Why not let a rebuilder like Econco give it a go and have them quote a price
for retro fitting the old boiler onto a new tube?  They may have done this
before.

Mike
W2AJI

----- Original Message ----- 
From: "Paul Christensen" <pchristensen at ieee.org>
To: "Mike schatzberg" <cherokeehillfarm at earthlink.net>
Sent: Tuesday, February 06, 2007 11:31 AM
Subject: Re: [Amps] 3CV1500A7


> That's another possibility but the retro-fit process is pretty complicated
> in order to maintain constant heat dissipation characteristics of the
> boiler.
>
> Paul, W9AC
>
> ----- Original Message ----- 
> From: "Mike schatzberg" <cherokeehillfarm at earthlink.net>
> To: "Paul Christensen" <w9ac at arrl.net>
> Sent: Tuesday, February 06, 2007 11:23 AM
> Subject: RE: [Amps] 3CV1500A7
>
>
> >I was under the impression that you could remove the boiler from the old
> >vapor cooled tube somehow, and reinstall it on the new 3CX1000.  Is this
> >not possible?
> >
> > 73,
> >
> > Mike
> > W2AJI
> > -----Original Message-----
> > From: "Paul Christensen" <w9ac at arrl.net>
> > To: "Juan Munoz" <tg9ajr at tg9ajr.net>; "Amps Amps" <amps at contesting.com>
> > Sent: 2/6/2007 10:14 AM
> > Subject: Re: [Amps] 3CV1500A7
> >
> >
> >> "A very good friend and my elmer has an Alpha PA-70V and he needs to
> >> replace the famous and almost disappear 3CV1500A7. Does anyone knows
> >> where
> >> we could find one or how this amps can be modify to accept another
> >> available vacuum tube?"
> >
> >
> > Juan,
> >
> >
> > The few new tubes that exist are locked up in our safe-deposit boxes.
> > The
> > 3CV1500A7 is electrically and in most respects, identical to the
> > 3CX1000A7.
> > The only difference is that the CV has a boiler fitted onto the anode
for
> > vapor cooling.  But the socket, and all other physical and electrical
> > properties are the same.
> >
> >
> > There are several possibilities:
> >
> >
> > 1) Send the tube to Econco for a rebuild estimate.  In speaking with
> > Econco's John Cavenary a few years ago, the success rate of a rebuild is
> > less than 50%.  The tube structure of that small power tube just does
not
> > hold up well to the forces required in the rebuild process.   Econco
> > should
> > be consulted first before sending them the tube.  Their policy may have
> > changed since the last time I spoke with them;
> >
> >
> > 2) Modify the amp with a 3CX1000A7 and add air cooling.  This involves
> > extensive metal work, but many 70V amps were converted by the Alpha
> > factory
> > and their customers back in the mid '70s.  "Instant-On" feature is
> > maintained; or
> >
> >
> > 3) Modify the amp with an 8877.  Same air cooling caveats apply, only a
> > time-delay system will need to be incorporated.  Not too terribly
> > difficult,
> > but challenging for some.  "Instant-On feature is lost."  Before Bob
> > Douglas, W5GEL became SK a couple years ago, he modified his 70V with
the
> > 8877 and we was very pleased with the results.   And, he did the mod at
> > near
> > 90 years of age.
> >
> >
> > I just recently purged the H2O system on my amp and it's as strong and
> > silent as ever.  Quick horror story: I purchased a gallon of "Brand X"
> > distilled water while standing in line at the local Walgreens.  Purged
the
> > water and added the Brand X water.  Powered-up and Leakage current went
> > off-scale.  Either I got a bad jug or that company is re-selling tap
water
> > as "distilled."  Purged the amp again three times and added ZephyrHills
> > brand and leakage current was back to zero!
> >
> >
> > FYI - for those interested in what the inside of a vapor-phase-cooled
amp
> > looks like, pictures of my 70V can be seen on Alpha's web site.
> >
> >
> > http://www.alpharadioproducts.com/html/70v_pix.htm
> >
> >
> > Paul, W9AC
> >
> >
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> >
>