Thanks for your replies.
I'm writing another reply but I realized that you help fill in more
of the serial numbers on my list. See my old post
<http://lists.contesting.com/archives//html/TenTec/2007-05/
msg00036.html>
So the list of mixers versus serial numbers in now includes yours.
525 00721 1496 VE7BGP
525 ????? PN ring KW7CD
525 01188 mixer? WA3FIY
525D 01611 ND487C1 N7WIM (with Argosy front panel)
525D 01810 ND487C1? WA3FIY
525D 02497 ND487C1 N7WIM (with Argosy II front panel)
But we're missing the mixer type in your 525. It would (help) confirm
the theory that the 1496 was dropped after S/N 00823 and that the
later 525 used a PN diode ring as mentioned in Dretea's article in
Ham Radio on Argosymods.
<http://members.aol.com/cdrentea/myhomepage/articles/argosy.htm>
Could you open up your 525 S/N 01188 and see what sort of mixer it
has: 1496, four discrete PN diodes or a small black four-legged
ND487C1 schottky quad.
You could confirm your 525D 01810 has a ND487C1? I'm certain it does.
If anyone else has a Argosy handy you could report your S/N and rx
mixer type too. It's easy. Take the top of the case off. Look at the
RF/Mixer board (80784 or 80784-D).
Does it have two 1496s U1 and U2 (two 14 pin dual in line ICs)?
or one 1496 U1 and a discrete set of (PN?) diodes between the two
small two-
hole toroids?
or one 1496 U1 and California Eastern/NEC ND487C1 a small round 4
legged "transistor-like" device between the two small two-hole toroids?
Send me the model, serial number, and mixer type.
73 Kevin
On Sep 26, 2007, at 11:45 AM, wa3fiy@radioadv.com wrote:
OK, I just looked up Kevin's post
http://lists.contesting.com/_tentec/2007-04/msg00326.html
and see the note about a change effecting the noise blanker at S/N
824. I'll bet
a cup of coffee and donut that is when the 525 analog got the diode
ring mixer.
Note that the 525 continued shipping some time after that. Just
looked. My
latest 525 has S/N 1188 and my newest 525D has S/N 1810. So the model
number switch came somewhere in between. I have successfully used the
same noise blanker in both analog and digital Argosys. Probably
means that
there is one version of blanker for 1496 mixer versions and another
for the
diode ring mixers.
Right on the money!
--
73 DE N7WIM / G8UDP
Kevin Purcell
kevinpurcell@pobox.com
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