My K2 no longer transmits.....which components might need replacing?

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

My K2 no longer transmits.....which components might need replacing?

stephen Farthing
Hello everyone,

    During the alignment of the Top Band option of my K2 I did a stupid thing and connected the dummy load to the wrong antenna connector. I used the tune button and tried to align the filters to set the TX power using the power level set to 2 watts. I got a high current warning on the display and then no power out. So it looks like I have damaged the PA by transmitting into no load. The net result is that I have no TX on all bands. There was no smoke, no excessive heat and no visual damage to components. The K2 ATU option displays 0.1:1 when I hit the tune button (incidently I thought the K2 should display power out when the tune button is pressed) and the Motorola test set I use indicates 0 power out. RX seems fine.

    I can only work on the rig at the weekends and there is no friendly component shop handy where I live. Clearly I will need to replace something. So I was thinking of ordering the components which might have failed by mail order and what I dont use will go into my spares store. Any ideas what I should order and or where the fault might lie....

    Thanks in advance,

Steve
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Reply | Threaded
Open this post in threaded view
|

RE: My K2 no longer transmits.....which components mightneed replacing?

Don Wilhelm-3
Steve,

If you want to have all the components that possibly could have failed
available, you could order one of every part in the K2 and the ATU transmit
chain!

For a more sensible approach, you must first do some isolation steps.
First remove the KAT2, then see if you have power out of the basic K2.
If the basic K2 is not transmitting, then use an RF Probe (one came with the
K2 kit) or a 'scope and follow the steps for Transmit Signal Tracing that
are shown in the K2 manual Appendix E.

Once you have localized the problem stage, then you can more easily isolate
to the failing component.  You likely only have one thing that has failed.

This kind of orderly approach to troubleshooting is more productive than
just replacing a bunch of parts in hopes that you get to the bad one - that
'shotgunning' approach has only a small chance of fixing the problem and can
lead to damaged boards and other frustrations.  The initial steps to
troubleshooting are outlined in the Appendix E of the manual, and can often
resolve the problem quickly if it is not difficult.  More obscure problems
can usually be found by the signal tracing steps outlined in the manual.

73,
Don W3FPR


> -----Original Message-----
>
>     During the alignment of the Top Band option of my K2 I did a
> stupid thing and connected the dummy load to the wrong antenna
> connector. I used the tune button and tried to align the filters
> to set the TX power using the power level set to 2 watts. I got a
> high current warning on the display and then no power out. So it
> looks like I have damaged the PA by transmitting into no load.
> The net result is that I have no TX on all bands. There was no
> smoke, no excessive heat and no visual damage to components. The
> K2 ATU option displays 0.1:1 when I hit the tune button
> (incidently I thought the K2 should display power out when the
> tune button is pressed) and the Motorola test set I use indicates
> 0 power out. RX seems fine.
>
>     I can only work on the rig at the weekends and there is no
> friendly component shop handy where I live. Clearly I will need
> to replace something. So I was thinking of ordering the
> components which might have failed by mail order and what I dont
> use will go into my spares store. Any ideas what I should order
> and or where the fault might lie....
>
>     Thanks in advance,
>
> Steve
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com