More problems with K2 #5061

[M. P. Haynes]

Hello again folks,

A week or so ago I contacted Gary about a problem with excessive current
on Q6 when I was trying to do the 40 meter transmitter cal.  Turns out
that Q10 was shorted driving the base to 4 volts key down.  Replaced Q10
and that problem is fixed.

Now, however, the VFO is inoperative.  It had worked FB before and the
receiver seemed very hot.  Now I can hear background noise and QRN but
can't tune in stations.  The readout changes like it should but the
oscillator stays at one frequency.  I verified this with an external
frequency counter as well as the built-in one and same with a spectrum
analyzer.  The oscillator is running and it puts out RF as it should but
not on a given frequency.  With 80 meters selected I get the following
frequencies; TP1 7788.6, TP2 4914.17, TP3 12092.17. I checked U6B pin  5
and get the 4V ref, pins 6 and 7 never change their values regardless of
turning the frequency knob.  Am I overlooking something?  Is there some
hidden menu I might have activated?  I was very careful when removing and
replacing Q10 and besides, it isn't anywhere near the affected circuitry.
 Any ideas?

73,

Pat Haynes-K4BEH
_______________________________________________
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

[Don Wilhelm-3]

Pat, re-check your R30 voltages.  You may have something associated with T5
and the rest of the VFO that is not soldered - an unsoldered connection may
work FB one day and fail the next.

73,
Don W3FPR

> -----Original Message-----
>
> A week or so ago I contacted Gary about a problem with excessive current
> on Q6 when I was trying to do the 40 meter transmitter cal.  Turns out
> that Q10 was shorted driving the base to 4 volts key down.  Replaced Q10
> and that problem is fixed.
>
> Now, however, the VFO is inoperative.  It had worked FB before and the
> receiver seemed very hot.  Now I can hear background noise and QRN but
> can't tune in stations.  The readout changes like it should but the
> oscillator stays at one frequency.  I verified this with an external
> frequency counter as well as the built-in one and same with a spectrum
> analyzer.  The oscillator is running and it puts out RF as it should but
> not on a given frequency.  With 80 meters selected I get the following
> frequencies; TP1 7788.6, TP2 4914.17, TP3 12092.17. I checked U6B pin  5
> and get the 4V ref, pins 6 and 7 never change their values regardless of
> turning the frequency knob.  Am I overlooking something?  Is there some
> hidden menu I might have activated?  I was very careful when removing and
> replacing Q10 and besides, it isn't anywhere near the affected circuitry.
>  Any ideas?
>
>

_______________________________________________
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