I have pretty much isolated it down to the transformer. Everything else that I
can check with the equipment that I have without desoldering absolutely
everything has checked out good including the rectifiers, caps, and the pass
transistors which I have desoldered and put back in place. The terrible
hum/vibration is definately coming from the transformer. Even cranked on it a
bit to tighten it up and to tighten it to the frame of the supply better with
no help as it was already tight. I have had a previous problem with this
Pyramid 35A supply about 6-7 years ago with a constant vibration so I think
this must have been a lamination issue. Anyway, I have pretty much written off
the Pyramid since this is the 2nd problem I have had with it. I know alot of
people that swear by the Astron 35A and I like them too but I have used one of
those before (that a friend of mine owns) while portable and it could not stick
with my Pyramid. We switched the 2 out a couple of times and the
Astron
could not handle the Mirage amp and the radio. I suspect we had a little low
line voltage from a long line from the generator...but like I said the Pyramid
had no problems and the Astron could not maintain it's voltage under load.
Anyway, I have pretty much narrowed it down to theses switchers.....MFJ 40A,
Diamond 40A, and the Diawa 30A with the Diamond being very borderline on
current (but has excellent reviews). I say MFJ because if their warranty and
an excellent local dealer, Diamond because of high current and lots of outlets
like the MFJ (even if only 1 meter), and again the Diawa for excellent review
on eham.net scoring a 5 out of 5, has a carry handle and rubber bumpers front
and rear for some more durability while portable.......Rusty NE4ME
Message: 1
Date: Mon, 27 Sep 2004 06:28:43 -0500
From: "DUGAS, JASON A. (JSC-EP) (NASA)"
Subject: [VHFcontesting] RE: VHFcontesting Digest, Vol 21, Issue 28
To: "'vhfcontesting@contesting.com'"
Cc: "'ae4bk@yahoo.com'"
Message-ID:
<85C9C005BF775C489985049627BD5E78CF93DF@jsc-mail07.jsc.nasa.gov>
Content-Type: text/plain
Rusty,
I doubt you will find another power supply that has the successful,
combined-operating hours as the Astrons. You mentioned a 25A-- consider the
35A version. I have been using 2m SSB rigs + the 3016 amp for years now
with not a single problem and I bought mine used several years ago. While
I'm a power electronics engineer, I haven't done any tests per se on the
ASTRONs but I can tell you that I typically stick with what works-- if you
get the right ASTRON power supply for your application (35M has the voltage
& current meters on the face) I'm certain it will work well for you.
You might consider repairing your Pyramid... Power Supplies tend to be good
projects since their operation is well understood by many...
Jason
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