[Amps] Alpha 99

[Carl]

----- Original Message ----- 
From: "Jim Thomson" <jim.thom at telus.net>
To: <amps at contesting.com>
Sent: Wednesday, April 26, 2017 11:06 AM
Subject: [Amps] Alpha 99


> Date: Tue, 25 Apr 2017 18:52:14 -1000
> From: Merv Schweigert <k9fd at flex.com>
> To: amps at contesting.com
> Subject: [Amps] Alpha 99
>
> Any Alpha 99 gurus out there,  I have an early model 99 with the tapped
> plate choke and clapper system.   The clapper has finally a hole burnt
> in it,
> and I was thinking I have seen a late model 99 with just a choke in place 
> of
> all that relay / clapper junk.   I usually use Ameritron chokes in my home
> brew amps and hoping one will fit the 99,  has any one done this?
>
> Also does any one have updates and setup information on setting the 
> various
> pots on the control board?
>
> Need to pull the amp out of service and replace the rear wafer on the band
> switch,  it was not aligned when built and the rear wafer is 1/2 step
> off,  thus
> burning a contact or two.
>
> Thanks  73 Merv K9FD/KH6
>
> ##  I believe the alpha used a 2 section plate choke, and the bandswitch 
> shorted out
> one section of the plate choke, when on the higher bands.  Done, so both 
> windings
> wont series resonate on the upper bands.  The henry 8 k ultra did the same 
> thing, but
> used a relay.   Later alphas ripped off the gapped choke idea from 
> ameritron, and
> came out with their own version.   IF the newer alpha  gapped choke fits, 
> and is not
> too long vs the oem choke, its should work.   The ameritron choke, IF it 
> fits, should
> also work.
>
> Jim  VE7RF


Actually Ameritron ripped off one from QST years earlier without giving any 
credit.....no surprise there considering who was involved playing injuneer.

Then it took them three tries using amp owners as the test bed to get it to 
actually work.

Ived used the Ameritron in several Alpha's in the 76 and 78 series, a bit 
tight horizontally but doable with an insulating sleeve going past the 
blower. The 87A is also doable if that switched choke and relay becomes 
toast.

Carl 


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