[Elecraft] FW: Problem with the ADSP2 for the 817

[Bruce Thompson]

For those of you installing the KDSP into your K2's, I thought you might
like to hear about my effort at putting a DSP unit into my 817.  It
definitely can be worse!   Any "constructive" suggestions as to how to
repair it?

Bruce KG0SH

P.S.  My "low audio" K2 developed an oscillation in the AGC after
installing the KDSP.  (Doesn't appear to be a problem with the DSP unit
as the problem remains after removal).  I gave up after too many hours
trying to debug it and sent it to Gary.  I'll let everyone know what it
was as soon as I know.  Meanwhile, enjoy your field day.  Looks like
I'll have to get a backup of my backup radio.
>  -----Original Message-----
> From: 	Bruce Thompson [mailto:brucet622@attbi.com] 
> Sent:	Saturday, June 28, 2003 1:24 PM
> To:	'sgc@sgcworld.com'
> Cc:	'FT817@yahoogroups.com'
> Subject:	Problem with the ADSP2 for the 817
> 
> I haven't seen any discussion of the SGC ADSP2 installation in an 817
> so I thought I would document my disaster when trying to do the
> installation.  Note that I have all the needed tools for surface mount
> work as well as the required documentation and have a lot of
> experience at kit building.  
> 
> I now have a non-functioning 817.
> 
> Here is what I found when I attempted to install my ADSP2 in my 817.
> 
> 1.  Read the fine print carefully on the installation instructions.
> (Why did they put that in such tiny font?)  You just about have to
> have a service manual to do this modification.  The service manual has
> the part layout diagrams with the part designators on them.  
> 
> 2.  The installation instruction photo showing the DSP board with the
> connection descriptions has lines that don't go to a pin.  Only the
> first four appear to be drawn correctly.
> 
> 3.  The resolution of the photos and the schematic diagram are not
> really high enough to see where the wires should actually go.  A good
> example is the schematic showing C1338.  It is pretty much unreadable.
> 
> 4.  The color of the wires that came with my unit were different than
> the one used in the photographs in the installation instructions.  One
> of the wires, the gray one, had a redefined function.
> 
> 5.  Removing the C1338 was much easier with two soldering irons.  
> 
> 6.  My surface mount iron has a 1/64" inch tip.  This was a bit too
> small to do this type of soldering.  I had to change it to a 1/64 x
> 1/32" blade tip.
> 
> 7.  In order to get at the place to solder the wires on, you have
> remove the larger of the two main PC boards in the 817 and solder on
> it's backside.
> 
> 8.  As with any surface mount work, a lighted magnifier of some kind
> is highly recommended.
> 
> 9.  And this is the disaster, when I was putting the board back in
> (watch out for the three long pin connector to the other board), the
> wires soldered onto the pads of C1338 lifted off the board taking the
> pads with them.  No pads now on the PC board.  I tried to see if there
> was any way to solder onto what was remaining but with no luck.  Seems
> as if the strength of the wires when they were bent over were strong
> enough to pull off the boards bringing the pads with them.   (And no,
> I didn't use excessive heat.  See comment about the tip size above)
> 
> Any ideas on how to fix this?  Since the PC board is the most
> expensive part on the unit..  
> 
> Anyway, I can't recommend this unit at all.  Enter at you own risk.
> Stick with a Clearspeech unit if you know what's good for you.
> 
> Looks like I'll be reading about field day since my Elecraft K2 is in
> the shop.  Please post how much fun you're having..
> 
> 
> Bruce "completely disgusted" KG0SH
> Golden, CO


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