[Elecraft] XV144 - power out with no drive

[Stewart GM4AFF]

Hi Don,
Input set to 1mW and using a K3 with a proper cable. When I switch back to
receive the XV144 always switches back to receive - like I said, I can still
hear louder stations. This doesn't mean that something on the board isn't
continuing to emit some kind of RF though.
The LEDs don't flash, they just illuminate and stay that way until I switch
off the 12v DC power.
I received another reply off-list from someone with a similar problem who
suggested contacting Elecraft for a fix.
73
Stewart

-----Original Message-----
From: Don Wilhelm [mailto:w3fpr at embarqmail.com] 
Sent: 14 December 2014 19:20
To: Stewart GM4AFF; elecraft at mailman.qth.net
Subject: Re: [Elecraft] XV144 - power out with no drive

Stewart,

What input level do you have the XV144 set for?  The 1mW level from the
KXV3 or the high power input from the K3 ANT1 or ANT2 jacks?
It is important that I know before I can venture a reasonable guess.

Are you using the Elecraft transverter cable to operate the XV144, or do you
have it configured for non-Elecraft and keying it with the PTT line (you
should have one or the other, but not both).  See the XVnnn Owner's Manual.


One thing you can do is see if the XV144 is staying in transmit when it
should be switching back to receive.  When in receive, what is the voltage
at the cathode of D4 - this is the 12T signal and should be zero during
receive.

The "all flashing LEDs" condition is an indication of an overload condition
or getting RF input while the XV144 is still in receive. If you are using
the 1 mW RF input, it should never trigger that condition.
There are some XVnnn transverters that falsely detect an overload condition.
That is due to noise on the COR detection line.  An easy cure for that is to
remove the front panel metalwork and solder a 0.1uf capacitor between the
collector and emitter of Front Panel Q7.  It can easily be added to the
solder side of Q7 without removing the front panel board.

73,
Don W3FPR

On 12/14/2014 9:52 AM, Stewart GM4AFF wrote:
> I have an intermittent problem with my XV144 (driven by a K3). On 
> transmit I can see power output on the LEDs (3 greens) even when there 
> is no audio input and the transverter is getting quite hot. Stations 
> tell me my signal sounds fine with no background noise. So it's generating
RF somewhere else!
>
>   
>
> Also, more seriously, occasionally, when I return to receive after 
> transmitting, the transverter LEDs all illuminate, I lose receive 
> sensitivity almost completely, although I can still barely hear louder 
> signals. The transverter won't transmit unless I switch off and on the 
> K3 and the XV144. This occurs more often as the transverter heats up.
>
>


-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.5577 / Virus Database: 4235/8734 - Release Date: 12/14/14