[Elecraft] K2 VFO Freq Display Stuck (again)

[Don Wilhelm]

Casey,

Yes, you did the measurements correctly, but there is some confusion in 
my mind about the EncRD signal.  Certainly with no load connected the 
voltage on U3 pin 14 should be 3.3 volts or higher.  So U3 must be 
replaced for certain.

Just as clarification, 0.4 volts is equal to zero in the digital realm 
and 0.46 is equal to 5 volts nominal - the data is "binary", so it is 
either ON or OFF - in other words, less than 1 or 2 volts and greater 
than 3.5 volts for TTL levels.

One more check on the encoder - see if leads 3 and 4 switch voltages 
together - if they do, there is something shorted in the encoder and it 
must be replaced.  If they are independent, replace only U3 and test again.

Sorry for the lack of a definite answer, and I understand that VK-land 
is not a 2 to 3 day parts request to delivery time, but based on the 
info I have, that is the best answer I could muster.

73,
Don W3FPR


On 6/17/2012 7:17 PM, TI2/NA7U wrote:
> Yes, I remember that Enc B was fine last time, also, but it's definitely not
> now.
>
> One correction to my previous post, when the encoder is connected the
> voltage on Enc B and Enc RD vary between .4-.46V, not from zero.
>
> With the encoder pins 3 and 4 disconnected and measuring directly at the
> encoder pins I see the voltage hold about 4.4V on both 3 and 4. As I turn
> the encoder the voltages on either pin drop to zero, but only
> intermittently.
>
> The voltage at U3 pin 14 is about .3V (even when the encoder pins are
> connected it measures about .1V, whereas the voltage chart says it should be
> 3.1V and varying).
>
> Hope I did the measurements correctly.
>
> 73,
>
> Casey
>
> -----
> Cloud Warmer Ham Radio Blog
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K2-VFO-Freq-Display-Stuck-again-tp7136782p7557747.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>