[Elecraft] K3 Hardware Updates

Sun Aug 23 23:19:19 EDT 2009

I believed Eric's statement to be true however Ron has experienced
problems with his radio performing unsolicited QSY's after her performed
the mod but forgot to change the menu setting.  

I have the mod in my radio and just tried to get something to happen w/
my radio set back to SPI1.  I tried on all bands and even ran a tune
into a dummy for a bit to get things to heat up a bit.  

Anyway if you're not hearing the noise then waiting a bit probably won't
cause you any issues. 

~Brett

On Sun, 2009-08-23 at 20:08 -0700, Joe Planisky wrote:
> Hi Ron,
> 
> > Eric and my statements are quite correct, both of them!
> 
> OK, I'm really missing something then.  Eric said (emphasis mine):
> 
> > There is no downside to making this h/w mod, EVEN IF YOU DO NOT  
> > ENABLE THE MENU OPTION.
> 
> That sounds very much like he's saying you can make the mod and not  
> change the SPI bus clock rate to SP2.
> 
> But you just said (again, emphasis mine):
> 
> > If you add the diodes and resistors per the App Note, ... YOU *MUST*  
> > CHANGE THE SPI BUS CLOCK RATE TO "SP2" FOR PROPER (STABLE) OPERATION.
> 
> I don't see how they can both be correct.
> 
> The reason I would like clarification is that I sometimes go back to a  
> previous FW release to compare operation with the new release.  If  
> what you say is true, that implies that once I make the hardware mod I  
> can't go back to the 3.19 release without potentially having VFO  
> stability issues.  If that's really and truly the case, I don't want  
> to do the mod until I'm sure I won't ever want to go back to anything  
> older than 3.24.
> 
> 73
> --
> Joe KB8AP
> 
> 
> 
> 
> On Aug 23, 2009, at 7:05 PM, Ron D'Eau Claire wrote:
> 
> > Eric and my statements are quite correct, both of them!
> >
> > If you add the diodes and resistors per the App Note, which provide  
> > better
> > termination on the synthesizer control lines, you *must* change the  
> > SPI bus
> > clock rate to "SP2" for proper (stable) operation.
> >
> > V 3.24 (or later) firmware has a menu command that allows you to  
> > change the
> > SPI bus clock rate as needed.
> >
> > The K3 works perfectly with that change, but with much reduced noise  
> > while
> > turning the VFO on the 6, 10 and 60 meter bands, at least for those  
> > who
> > experienced the noise.
> >
> > A few people have downloaded the newer firmware (3.24 or later) and  
> > tried
> > changing the SPI clock rate without installing the diodes and  
> > resistors that
> > terminate the synthesizer control lines. Doing that leads to unstable
> > operation.
> >
> > Similarly, I installed the diodes and resistors (while illustrating  
> > the App
> > Note), forgot to change the SPI clock rate, and found my VFO unstable.
> >
> > After some head-scratching I realized my oversight, changed the SPI  
> > bus
> > clock rate to "SPI 2" and everything is perfect again.
> >
> > So the K3 is perfectly stable without installing the parts, no  
> > matter which
> > version of the firmware you install, provided you leave the menu  
> > command for
> > the SPI Bus rate at CONFIG:MD SPI 1.
> >
> > Similarly  the K3 is perfectly stable with the diodes and resistors
> > terminating the synthesizer control lines provided you change the  
> > SPI bus
> > rate to CONFIG:MD SPI 2
> >
> > Ron AC7AC
> >
> >
> >
> > -----Original Message-----
> > From: elecraft-bounces at mailman.qth.net
> > [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Joe Planisky
> > Sent: Sunday, August 23, 2009 6:24 PM
> > To: Elecraft Reflector
> > Subject: Re: [Elecraft] K3 Hardware Updates
> >
> > Now doggonnit, let's get our stories straight!
> >
> > Ron D'Eau Claire says:
> >
> >> ... if you add the resistors and diodes and do not
> >> change the timing, the VFO may become unstable,
> >
> > Eric Swartz says:
> >
> >> There is no downside to making this h/w mod, even if you do not  
> >> enable
> >> the menu option.
> >
> > Am I missing something, or are these two statements contradictory?
> > Maybe Wayne can be the tie-breaker :-)
> >
> > 73
> > --
> > Joe KB8AP
> >
> >
> >
> > On Aug 23, 2009, at 4:08 PM, Ron D'Eau Claire wrote:
> >
> >> Well, it shouldn't hurt to do the mod, but I agree with David if you
> >> can't
> >> find any noise.
> >>
> >> The reason 3.24 is required is that it provides a menu entry for
> >> changing
> >> the bus timing as described in the procedure. A slightly different
> >> timing is
> >> required for stable operation once the diodes and resistors are  
> >> added.
> >>
> >> If you try to load the firmware and change timing without adding the
> >> resistors and diodes, or if you add the resistors and diodes and do
> >> not
> >> change the timing, the VFO may become unstable, making un-commanded
> >> QSYs.
> >> (On my K3 they were in 100 Hz steps.)
> >>
> >> The default timing in all the firmware, including 3.24 and up, is
> >> correct
> >> for K3's that do not have the diodes and resistors added, so you
> >> need do
> >> nothing after upgrading your firmware if you haven't added the
> >> parts. Your
> >> K3 will continue to work FB just as always.
> >>
> >> A revised mod procedure will be posted Monday to make that point
> >> clear.
> >>
> >> Ron AC7AC
> >>
> >
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