[ETO_Alpha] Followup - CW/SSB switches for Alpha 76?

[Dave Haupt]

Wow, I didn't expect to start a maelstrom!

I may be guilty of overly-condensing my original
request.

I have an on-again, off-again project going on here. 
The amplifier I acquired is a model 76 CM ii.  It was
built for use in some medical laboratory experiments,
and covers 14 to 60 MHz in six bands.  The name on the
front panel is not ETO or Alpha, but instead, the name
of the customer for which ETO custom designed the
amplifier.  In addition to the different frequency
coverage, the amp only needed to deliver
millisecond-level pulses, so it's only equipped for
one 8874 tube, which did not come with the amplifier. 
It also is without the SWR monitoring board, and has
no T/R relay.  RF input is via BNC.

Clearly, this amp has been elsewhere since then, as it
wears equipment ID tags for, among other things, a
surplus test equipment dealer, and a US Navy ship
"recreational facility" - I assume an onboard ham club
that planned to turn the amp into a ham amp.

To turn the amp into a ham amp just like the model
76's they sold "for us", I need to replace the entire
tank, including bandswitch, and remove the
bandswitched input and replace with the broadband
circuit that ETO used.  I will be equipping it to
operate the more readily-available 3CX800A7 tube.  

I'm using the project as an exercise in frugality and
was pleased to be able to find the OEM variable
capacitors surplus and the tech support guys at
Crosslink have been generous in helping me understand
what windings need to be on those ferrite inductors
and what the cores are.  Rather than duplicate the OEM
T/R switching, I'm going to use a fast PC-mount relay
system that I devised some months ago.  QSK speed with
low cost relays.  I haven't come to any decision on
how I'm going to get around the absent SWR board
though - anybody have one from a parted-out amp, or a
conversion to six meters?

When I posted my request for SSB/CW/Standby switch, I
was hoping that somebody had parted out a 76, and had
the switches available.  I knew I'd be able to get
them from the present owners of Alpha, but was simply
trying to fit this request in with the frugal nature
of the project overall.

Any time I've contacted the Crosslink folks about this
amp (or other Alphas that I repair from time to time
for other hams) I have received the best customer
service I could hope for.   When I lived in Colorado,
my employer did some joint projects with Dick Ehrhorn,
and later I had the pleasure of working on a project
with AE0Q, the present service manager.  All top notch
people, and there is no doubt in my mind that they
plan to continue to support their legacy amps.

In the case of the switches, I'm pleased that Glenn
has posted the part numbers and I will proceed to
order new parts.

So, now you know the rest of the story!

73,

Dave W8NF


		
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