[Boatanchors] Valiant VFO jumping

[Singley, Rodger]

Paul,

First, have you changed the VR tube dropping resistor in the VFO?  If not do so because the original overheated resistor can cause this problem (and will cause other problems over time).

If this has already been done, before you go into the VFO try a substitute for the keyer tube if it is more of a warble than a major frequency jump.

If this doesn't cure it then it could be a number of items including the oxidized contacts of either VFO tube, the VR tube, the VFO tube, wiper oxidation on the VFO tuning cap, and a bad mica cap in the VFO.  I would suspect the tubes as being the most likely culprits.

Resistor and tube replacement can be done with the VFO still mounted.  To get to the resistor you need to remove the cover on the left side of the VFO (your left facing towards the rear of the rig).

Rodger WQ9E




-----Original Message-----
From: boatanchors-bounces at mailman.qth.net on behalf of Paul Baldock
Sent: Sun 1/31/2010 3:04 PM
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] Valiant VFO jumping
 
The VFO in my Viking Valiant is jumping around.

Is it possible to get inside the VFO, maybe reseat the 6AU6, without 
completely removing the module from the chassis?

Thanks

- Paul

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