K2 cannot be swithed ON properly.

[Ueli Zulauf]

After years of operation my K2 cannot be swithed ON properly.
- Configuration: K2 (No. 3680) with KDSP2, KSB2, KNB2, KAT2, K160RX.
- By switching ON the display shows Elecraft for 3 seconds and thereafter the last used frequency (28.15 MHz).
- All keys and the VFO are inactive.
- Current drain is 400mA (to high).
- Noise of several relays during power-ON is audible.
- Speaker brings (AF-gain dependend) audio for < 1 second and thereafter the audio is muted.
- by changing TX power, the level appears on display as normal.
- Transmit is not possible.
- LED on KDSP2 extinguish after < 1 second (communication schould be OK)
- 5 VDC and 8 VDC on the control board are OK.

Has someone a good idea how to de-freeze this blocked K2 ?

73, Ueli / HB9MFK
--
Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 -
sicherer, schneller und einfacher! http://portal.gmx.net/de/go/atbrowser
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Geoffrey Mackenzie-Kennedy]

Ueli,

My K2/100 #3255 has frozen on two occasions.

Try removing the MCU (U6) on the Control Board from its socket, and then
plug it back into its socket. Doing this should clean the connections
between the IC and its socket, and should defrost your K2 if that is the
source of the problem..

Because the type of socket used is well known for "corrosion" problems,
after the second "Freeze" I changed U6's socket in my K2 to a Turned Pin
type (aka Machined Pin type).

Good luck!

73,
Geoff
GM4ESD


Ueli Zulauf HB9MFK wrote on Wednesday, September 23, 2009 at 5:06 AM

> After years of operation my K2 cannot be swithed ON properly.
> - Configuration: K2 (No. 3680) with KDSP2, KSB2, KNB2, KAT2, K160RX.
> - By switching ON the display shows Elecraft for 3 seconds and thereafter
> the last used frequency (28.15 MHz).
> - All keys and the VFO are inactive.
> - Current drain is 400mA (to high).
> - Noise of several relays during power-ON is audible.
> - Speaker brings (AF-gain dependend) audio for < 1 second and thereafter
> the audio is muted.
> - by changing TX power, the level appears on display as normal.
> - Transmit is not possible.
> - LED on KDSP2 extinguish after < 1 second (communication schould be OK)
> - 5 VDC and 8 VDC on the control board are OK.
>
> Has someone a good idea how to de-freeze this blocked K2 ?
>
> 73, Ueli / HB9MFK

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Ueli,

That sounds like your K2 may have 2 problems.
1) It is going into transmit immediately after power-on
2) It has no power output.

Check for condition 1 first.  Remove the top cover and measure the 8T
and 8R voltage rails. These can easily be reached on the RF Board at the
anodes of D6 and D7.  Normally during receive, only the anode of D6 will
have a voltage in the 7 to 8 volt range, and only the anode of D7 will
have voltage during transmit.  Check both.  If there is voltage on both
D6 and D7 then it is trying to transmit ans receive at the same time.  
In case of abnormal behavior of these voltages, de-bug it at the source
(Q1, Q2, Q3 and Q4) on the Control Board to find the real reason of the
problem.

Only after finding the source of the locked K2 and the high current
after turn-on should you investigate any lack of power output.

73,
Don W3FPR


Ueli Zulauf wrote:

> After years of operation my K2 cannot be swithed ON properly.
> - Configuration: K2 (No. 3680) with KDSP2, KSB2, KNB2, KAT2, K160RX.
> - By switching ON the display shows Elecraft for 3 seconds and thereafter the last used frequency (28.15 MHz).
> - All keys and the VFO are inactive.
> - Current drain is 400mA (to high).
> - Noise of several relays during power-ON is audible.
> - Speaker brings (AF-gain dependend) audio for < 1 second and thereafter the audio is muted.
> - by changing TX power, the level appears on display as normal.
> - Transmit is not possible.
> - LED on KDSP2 extinguish after < 1 second (communication schould be OK)
> - 5 VDC and 8 VDC on the control board are OK.
>
> Has someone a good idea how to de-freeze this blocked K2 ?
>
> 73, Ueli / HB9MFK
>  
>  

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Brian Mury-3]

On Wed, 2009-09-23 at 08:26 -0400, Don Wilhelm wrote:
> That sounds like your K2 may have 2 problems.
> 1) It is going into transmit immediately after power-on

I've had this happen in SSB mode with the VOX turned on because the mic
was picking up a steady noise (such as a computer fan). It's easy to
check - unplug the mic!

Could also be a PTT signal from an external source such as a PSK31
interface.

Check the easy stuff first!


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html