[Johnson] Johnson Ranger Problem -part 2

[Gary Schafer]

Hi Wayne,

I don't have a ranger but took a quick look at the ranger schematic. It 
looks like the screen voltage for the clamp tube comes from the same 
adjustable resistor that controls the modulator screen voltage. Check to 
see if the modulator screen voltage is set right. That might cure the 
problem. If the clamp tube screen voltage is too high it will conduct 
more than it should.

It sounds like the clamp tube is not fully turning off and is dragging 
the 6146 screen voltage down. As you tune the plate tuning the screen 
current will vary and so will the grid current. Both will have an effect 
on the clamp tube.

Also check the grid resistor on the clamp tube to see if it is in the 
ball park.

As I mentioned before, if you do not have the proper amount of grid 
drive the clamp tube will not be fully cut off and it will drag the 6146 
screen down.

73
Gary  K4FMX


Wayne Light wrote:
> Hello all and thanks to those of you that sent me ideas.
>  
> Gary, you gave me a huge hint. I removed the Damper Tube -6AQ5...and without the tube, the transmitter works perfectly, including the nuturalization issue. I have normal plate voltage and full power output. 
>  
>  I've carefully checked all the wiring around the damper tube and it seems fine. I checked the tube, and it is strong. I checked the three resistors (11K total) and they were fine, the .005 cap is fine.
>  
> It makes me wonder if I could just forget the clamper tube and use the rig?  However, I won't do that since that circuit must be important.
>  
> Thanks again...anyone have an idea of where I can go from here?
>  
> Wayne
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