[Johnson] Valiant VFO

[Douglas Rowlett]

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.