[heathkit] drifting and jumping and chirping etc;;;;;;

[Alan Beck <becka@eastlink.ca>]

Thank you so much Bob,

BTW, I have never had SPOT mode work on any HR-10 VFO.

They have always been wired with the keying wire connected to the input
to the bulb and the other end left open.

This is, I believe the mod for the DX-40.

Perhaps I need to have a hard look at the voltage divider for the Grid
Block keying.

Best 73,

Alan



On Mon, 2008-02-06 at 12:42 -0400, G3OOU@aol.com wrote:
> Hi Alan
>  
> 1. Does the grid current variation also happen when using crystal
> control or only with the VFO?
>  
> 2. I have the DX60 circuit to hand plus that of the DX60B - not much
> difference in the RF side.
>  
> 3. The frequency variation could be because the problem is in the VFO
> or because the loading on the VFO is changing. If this happens in
> "spot" mode as well then it is probably not due to RF from the PA
> leaking into a sensitive circuit.
>  
> 4. Have you tried gently rocking the two 6CL6 valves in their sockets
> while listening to the Tx note in a local Rx?
>  
> 5. Check for corrosion on all chassis connections and any visible dry
> joints. Gently tap parts with a "rubber hammer" and see if the tone
> changes - something light and well insulated. IF that fails to find
> the problem then a freezer spray may be the bext best thing.
>  
> I have used grid block keying in early transmitters with a neon
> feeding the VFO control grid - worked well for me but the negative
> voltage must be high enough to strike the neon. I used -150v with an
> 85A2 or a VR105 to control the VFO and modified the Rx AGC to allow
> instant muting for full break-in. All homebrew.
>  
> Do some tests and let us know what happens.
>  
> 73
> 
> Bob 
> G3OOU
> G-QRP 6907
> http://members.aol.com/rfcburns