[Amps] Famous Alpha plate clip desoldering issue

[Carl]

Id say that the amp was the recipient of excessive drive at some point as a 
prior owner believed that another 200-300W would make a difference. Ive seen 
that desoldering as well as crystalized solder joints in the bandswitch area 
in several amps that were ridden hard and put away wet.

Im also a happy 76PA owner on the 2nd station. It was a former contest 
station amp from one of the Carribean big gun multi-multis and required a 
lot of TLC to get it back to its former glory. Thanks to my scrounging 
ability it was rather painless (-; plus it came to me as payment for fixing 
their Ten Tec Titan 425.

Carl
KM1H



----- Original Message ----- 
From: "Jeff Blaine" <keepwalking188 at yahoo.com>
To: <amps at contesting.com>
Sent: Thursday, September 16, 2010 1:01 AM
Subject: [Amps] Famous Alpha plate clip desoldering issue


>I picked up an old 76pa which seems to be in otherwise FB condition.  2400v 
>idle on the plate cooking away those pipes who have not been used in a 
>couple of years prior to some initial power testing tomorrow.
>
> Only strange thing I noticed on the inspection was that every single one 
> of the braid connections to the plate cap had delaminated.  The braid is 
> tarnished so I assume it's silver plated - hard to tell the condition of 
> the solder connection otherwise.  But the braid was lose enough that the 
> cap could be removed from the braid just by bending the braid slightly.
>
> I got to thinking about what could have caused that.  Came down to one of 
> three possibilities:
>
> 1. The famous alpha plate clip desoldering issue, known world-wide to all 
> Alpha owners but not to nubees who expect these things to be soldered in 
> the traditional way.  Not to worry though because....
>
> 2. The amp creates a virtual short when keyed down due to it's massive 
> high power output only to have the joint break again with key up.  A 
> technology known only to Alpha and is top secret such that RF Concepts was 
> unable to dig the secret from the ETO data archives.  The secret sauce 
> lost for all time.
>
> 3. OR - The dogs were whipped mercilessly at one time, so hard that their 
> anode temp rose high enough to desolder, AKA SB220 pins can sometimes do. 
> Say it's not so!
>
> Hoping some of the learned 76 owners may have some insight.
>
> There was some what appeared to be "melted" gasket material visible on 
> each tube.  Maybe 1/4 in long and a tiny fraction of an inch in height and 
> depth.  I say melted because it was stuck firmly to the tube and rounded 
> and shiny on the exposed surface.  Interesting because the sealing 
> material will break with age but in that case it generally has a rough and 
> "flat" appearance.
>
> 73/jeff/ac0c
> www.ac0c.com
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