Fw: K2 Problem 30/20

[Glenn Haffly]

Subject: K2 Problem 30/20

> K2 # 4869 fully functional except 30/20 meters.
> An external signal generator on these bands will
> allow trimmers C21 and C23 to be peaked. A
> strong external signal is barely heard.
> Items that have been checked:
> #1 L18 , L19 , L20 rechecked for proper amount
> of turns and solder joints Ok.
> #2 All capacitors in the LP area are the correct part
> and solder joints Ok.
> #3 All capacitors in the band pass filter are the correct
> parts and no solder joints.
> #4 Relays K4 and K9 oriented correctly.
> #5 Using Don's past words check solder joints and are Ok.
> #6 The correct transformers used at L8 and L9.
> #7 Trimmer caps with red dots are at C21 and C23.
> Observations : Placing a finger under L8 increases noise levels
> and touching a screwdriver to one end of most of the caps in
> the 30/20 BP area also increase the noise level to a point where
> strong outside signals can be heard.
> Current plans are to use the signal generator at the antenna connector
> and try to see where signal stops.
> All other bands are good on Rx and Tx.
> Any suggestions would be welcome.
>
> Glenn
> K5ZE

_______________________________________________
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]

Glenn,

Since you obtain a signal when touching the points in the bandpass filter
AND that the K2 works on other bands, I predict that you will find the
problem in the Low Pass Filter.  Either a Poorly Tinned Toroid Lead (PTTL)
or the points of relay K9 are not behaving properly.  Select either 20 or 30
meters then turn power off and measure the resistance between jumper W1 and
the antenna jack - if it is not close to zero ohms, you have confirmed that
the low pass filter is at fault.

73,
Don W3FPR

> -----Original Message-----
> > K2 # 4869 fully functional except 30/20 meters.
> > An external signal generator on these bands will
> > allow trimmers C21 and C23 to be peaked. A
> > strong external signal is barely heard.
> > Items that have been checked:
> > #1 L18 , L19 , L20 rechecked for proper amount
> > of turns and solder joints Ok.
> > #2 All capacitors in the LP area are the correct part
> > and solder joints Ok.
> > #3 All capacitors in the band pass filter are the correct
> > parts and no solder joints.
> > #4 Relays K4 and K9 oriented correctly.
>

--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.11.5 - Release Date: 5/4/2005

_______________________________________________
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