Have you asked Alpha lately for any info at all??
I have made many many calls to Alpha and 99 percent of them are
for naught. To talk to a tec was next to impossible, to gather any
info from anyone was also next to impossible, my experience, if you
have had better, good on ya mate.
It never hurts to ask Alpha for information instead of speculations...
The early 99 amps used a board at the front of the bandswitch (inside the
front subchassis) to turn on the plate choke relay that K9FD's amp has,
this relay pulls down the clapper arm to short out part of the plate choke
on higher bands. If the arm isn't adjusted to pull down solid enough, the
contact point can burn.
If anyone ripped off Ameritron it wasn't Alpha. Alpha changed to the RF
Parts RFC3 plate choke, bought in batches from RF Parts, then started
winding their own to the same specs. It will work in the earlier 99, no
other changes were made.
All the bandswitch wafers WERE aligned correctly when the amp was built,
how could it have passed a 48 hour transmitting burn-in? Who has been
poking inside of a 15 year old amp since it was originally adjusted?
The wafer was not aligned properly, this amp was number 2 if I remember
correctly,
I bought it from Alpha after it came back from a DX trip, for some
reason it was
being refurbished, it resided in a box for years until I moved to KH6
I had problems with it from day one, none of the bias settings were
correct, it
needed screen voltage changes etc. It was purchased right at the time
that Alpha was
changing hands and Brosnahan left and moved to Texas, what I got was a
very good
priced 99 (cheap) that was not "finished" with refurb. The switch
wafer is about 1/2 contact
off and has been that way since purchased. It was never correct. It
never passed any
24 hour burn in. Heck the transformer would not even fit the bolt
holes when I assembled
it.
Email Alpha for the 99 factory adjustment procedure.
http://www.alpharfsystems.com/
Glenn AE0Q
On Wed, Apr 26, 2017 at 9:06 AM, Jim Thomson <jim.thom@telus.net> wrote:
Date: Tue, 25 Apr 2017 18:52:14 -1000
From: Merv Schweigert <k9fd@flex.com>
To: amps@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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|