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Re: Replacement Crystals and ICM HC-49/Short Case- Does it or Doesn't it fit inside the 2880 ?



Hi Jim, Brial and All interested in the crystal for the Drake 2880....

My conversions were done long ago and I still have the old crystal that was 
removed from my 2880's...we converted one early last year, but the 
replacement crystal as noted in the text below was a bit too tall.  when 
the second 2880 was converted a new, different sized crystal was ordered 
through ICM..the replacement crystal that we used carries ICM's Catalog 
number 433490 and the general description is HA 26C (FX=7.5-10.99 MHZ) 
433492.....the correct frequency for the crystal is 8.812500. These 
replacement crystals have long pigtails for soldering and do not use a socket.

Not knowing the actual size of the one being discussed, I can tell you 
without question that the ones I purchased in August 00 were shorter than 
the original by almost 1/8 of a inch and approximately 1/8 of a inch in 
width...so it fit in fine without a problem.  I purchased two when I placed 
my order in August of 2000 and I still have the invoice that I can scan if 
anyone wants that specifically to look at.  I also kept one crystal because 
I knew there was going to be questions when and if the conversions were 
underway for this project, so I can compare the sizes without a problem.

The original 2880's that I purchased were unmodified and one crystal was 
included with the transaction...that crystal had to be tweaked in order to 
maintain the correct height within the Drake housing.  Although it was 
reconfigured on the board, no apparent abnormalities existed when the 
device was check and calibrated by K6ODV.. If anyone is interested I  can 
give specific dimensions of the HA series if anyone desires same...let me 
know....73's to all..

Happy 2880 Modifying!

Lonnie  (NT6B)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

At 11:14 AM 2/11/01 -0800, James R. La Frieda wrote:
>Brian - when you ordered your crystal from ICM- did you take care to specify
>that you wanted the HC-49 /short case ? - for I was under the impression
>that ICM HC-49 Short Case crystal holder would fit into the Drake 2880
>without requiring any of the 30 degree bending that you describe below ?
>What part # came with your crystal ? Was it Part# 540288 HC-18T Cold Weld
>Holder HC-49U  or something else? Many of us on the Amsat BB recently
>ordered our crystals in the last week or two- and hopefully the short case
>HC-49 should fit within the Drake 2880- or otherwise we need to change
>thecrystal holder.
>
>Please respond back ASAP.
>
>Many Thanks,
>Jim, N6MV
>
>
>
>----- Original Message -----
>From: "Brian Mitton" <brianm@pacsg.css.mot.com>
>To: <amsat-bb@AMSAT.Org>
>Sent: Saturday, February 10, 2001 6:25 PM
>Subject: [amsat-bb] Drake 2880 mod (XTAL)
>
>
> > Hi all,
> >
> > I got home late last night to find a box from ICM frozen to my porch,
> > so I had to come in tonight and mod up my new Drake.  It looks like
> > the surgery was successful, but I have one thing I really want to share.
> > The ICM crystal looked taller than the one it replaced, so I compounded
> > the situation by putting it on with a bit of room to bend it over.
> > I had to bend it about 30 degrees to get the lid on.  It really didn't
> > like to be touching the lid, so I put kapton tape over the top.
> > As I was tighting the lid I came to a point where the output would
> > jump almost 100 KHz (KC).  I noticed that the crystal case was touching
> > one of the chip caps, so with some tweezers I snuck a bit of kapton
> > tape down there as well.  It all seems to be working, but I am curious
> > if anyone else has tried putting in an ICM crystal, and if you have
> > had problems.
> >
> > My other observation, and this is probably a newbie question, is that
> > the hardest problem I had was getting that F connector un-soldered.
> > I worked on it with alot of solderwick and what I thought was patience,
> > but when I turned the nut-shaped-thing a piece of trace went with the
> > center conducter!  All the instructions start with the board out on the
> > bench ;)
> >
> > So I re-crystaled it.  Took out the red coils and green caps.
> > Put 18pf caps on either side of the green coil (all I have is 18 and 27)
> > Used clippings from the crystal leads to extend the bandpass filter.
> > Tweeked in the LO as best I could, and zipped it all up.  All in one
> > setting (two cans of coke).  It was really not that bad.
> >
> > Do I need more amplification or am I ready to move on to the antenna?
> >
> > 73 de N8NPA Brian
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
>
>----
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