[Johnson] Valiant VFO

[Douglas Rowlett]

Thank you Brian and Rodger for the suggestions. I will start there after I do a tube check.

Doug, WB5IRI

Sent from my iPad.

> On Mar 17, 2014, at 6:09 AM, "WQ9E at btsnetworks.net" <WQ9E at btsnetworks.net> wrote:
> 
> Doug,
> 
> With the symptom you describe I believe a dirty wiper on the tuning capacitor is the most likely culprit.  Any poor connection in the Valiant could cause this but I would start with cleaning the wipers on the tuning capacitor.  Access is not fun but you should be able to get there through the side sufficiently to address the wipers.
> 
> The W8JI described instability is largely from RF developed when actually transmitting so it isn't the culprit of these large random jumps while in standby.
> 
> Rodger WQ9E
> 
> -------- Original Message --------
>> From: Douglas Rowlett <douglas.rowlett at gmail.com>
>> Sent: Sunday, March 16, 2014 9:00 PM
>> To: "johnson at mailman.qth.net" <johnson at mailman.qth.net>
>> Subject: [Johnson] Valiant VFO
>> 
>> VFO was working fine on my Viking Valiant, but recently began exhibiting strange behavior. When first powered up, it acts normally, but after 5 minutes or so, attempting to adjust the frequency with the VFO knob causes the transmitter to jump to a random frequency somewhere in the band. As long as I don't touch the tuning knob, transmitter is stable and works normally. Touch that dial to zero beat, though, and away she goes. So, before I tear into this thing, any sage advice on where to start looking? Could it be as simple as a bad tube? Bad capacitor? Cold solder joint? Any advice to point me in the right direction so I don't spend hours in frustration will be appreciated.
>> 
>> Also, what's the best way into the VFO? Through the top, the side?
>> 
>> Doug, WB5IRI
>> 
>> Sent from my iPad.
>> 
>> Sent from my iPad.
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>