[Elecraft] K2 - hang up problem

Tue Feb 5 15:46:31 EST 2008

Hi Tony,

My K2 is working fine as well. I measured the KSB2 U1 voltages as
described by Don W3FPR and they appeared to be correct. 

Apparently, the problem was caused by my K20 CW keyboard, cf.
http://k1el.tripod.com/k20info.html

With the key plug of the K20 CW keyboard plugged into the key jack of
the K2, SSB receive signals decreased after I pushed the MH2 PTT button.  

After unplugging the K20 keyboard from the K2 key jack, SSB receive
signals were back to normal signal strength.  Next time I want to do
some SSB or PSK31 I have to remember that the CW keyboard needs to be
unplugged from the K2.

Thanks to you, Don and everyone else for the great support.  

vy 73,
Gunter PA3HGC

"N2TK" <tony.kaz at verizon.net> wrote:

> Hi Gunter,
> I do not know if this helped you or not. I did not take off  the
> covers of my K2 since it seems to be working fine. If I convert my
> XV50 to a XV144 I will  check out the problem.
>  
> Good luck with your problem.
>  
> 73,
> N2TK, Tony
> 
>   _____  
> 
> From: N2TK [mailto:tony.kaz at verizon.net] 
> Sent: Monday, February 04, 2008 5:05 PM
> To: 'w3fpr at arrl.net'; 'PA3HGC'
> Cc: 'Elecraft Discussion List'
> Subject: RE: [Elecraft] K2 - hang up problem
> 
> 
> Well, I got my K2 working again. Don't understand why, but it is
> working fine.
>  
> My K2 sits on a XV50. I had unplugged the 12V to the XV50 to use the
> 12V line for the K3. It turns out if I unplug the 12V line to the
> XV50 I also need to disconnect the RS-232 line between the K2 and
> XV50, even though the XV50 is not ON. Then the K2 works fine on SSB
> (it always worked fine on CW).
> 
>  
> If the 12V power  is plugged into the XV50 the RS232 line does not
> matter whether it is plugged into either the K2 or XV50 or both. But
> if the 12V power is removed from the XV50 the RS232 must be removed
> so the K2 works on SSB.
>  
> Maybe over a beer I need to look at the schematics to see what this
> is all about. As always, ideas are welcome.
>  
> Tnx for all the suggestions. Amazing how much help was offered. 
>  
> How about those Giants!
>  
> 73,
> N2TK, Tony
>  
>   _____  
> 
> From: Don Wilhelm [mailto:w3fpr at embarqmail.com] 
> Sent: Saturday, February 02, 2008 5:50 PM
> To: PA3HGC
> Cc: N2TK
> Subject: Re: [Elecraft] K2 - hang up problem
> 
> 
> Wow,  two with the same problem at the same time - that is unusual.
> You guys will have to take some measurements to guide me in the right
> direction - right now it seems like the problem is on the KSB2 board,
> but we need to confirm or deny that.
> 
> Open the K2 top cover - if a KPA100, lay it on a box to the right of
> the K2, but leave it connected.
> Receive with the OP1 filter for now.
> Then try to create the problem - when it occurs, it is time to take
> some measurements.
> Is RXS (U1 pin 21) high (5 to 6 volts)?  It should be.
> Are TXS (U1 pin 15), TXC (U1 pin12), and RXC (U1 pin 22) all low
> (near zero volts). They should be.
> If those signals are in the correct state for SSB (or RTTY) receive
> with the OP1 filter, then the firmware chip on the KSB2 board is
> doing what it is supposed to.  If not, then there is some firmware
> fault or some signals are not getting from the K2 to the KSB2 board.
> 
> If the signals are correct and the failure persists, then the task is
> to follow those signals into the diode switches for the filter and
> try to find what is bad.  It could be an unsoldered or poorly
> soldered connection.  You may want to reflow the solder on all the
> diodes near the filter and the R-paks too.
> 
> 73,
> Don W3FPR
> 
> PA3HGC wrote: 
> 
> Don, Tony,
> 
> 
> 
> Get an error message when posting to the Elecraft reflector ("Your IP
> is
> 
> in nl, rejected based on geographical location"), so I try to approach
> 
> you directly.
> 
> 
> 
> Since last week I have the same problem with my K2 # 703 on all bands,
> 
> i.e. receive and transmit in CW is perfect, receive in SSB and data
> 
> modes is okay, only if I push the MH2's PTT key in LSB, USB or data
> 
> mode and let the K2 go back to receive, the receive signals are much
> 
> weaker than before (typically from S9 before keying the PTT to S1
> 
> afterwards). I can only get back to normal reception by switching
> bands
> 
> or by switching the K2 off/on.
> 
> 
> 
> My control board firmware is 2.03d, and the KSB2 firmware is 1.07.
> 
> I have already resoldered the sockets of the firmware chips on the
> 
> control board and the KSB2 adapter and reseated U6 and U1, but the
> 
> problem persists with both the 10W K2 and the KPA100/KAT100-2 (in
> 
> EC2 enclosure) attached.
> 
> 
> 
> Thanks and 73,
> 
> Gunter PA3HGC
> 
> 
> 
> 
> 
> W3FPR wrote:
> 
> 
> 
>   
> 
> Try reseating the firmware chip on the KSB2 board, and if
> 
> that does not help we can begin looking at various voltages on the
> 
> KSB2.  The signals that switch the filter are RXS, TXS, TXC and RXC.
> 
> 
> 
> 73,
> 
> Don W3FPR
> 
>     
> 
> 
> 
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> 
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> 
> 
>   
> 