[Johnson] re: Valiant

[Gary Schafer]

If they are ceramic caps put in mica transmitting caps. Ceramic caps are 
unstable and change values with current. They can not handle tank 
circuit currents. They are fine for bypassing but NOT as tank padders.
Be sure that they are rated for several amps of current.

73
Gary  K4FMX


skip wrote:
> RE: A2 type transmitting cap from Surplus sales of Nebraska.
>        These are supposed to be 2.5kv tested to 5kv ceramic mica caps.  They
> are about 3/8" thick 1 1/4" sq with mounting holes on the ends.
> 
> Finals are 6146 RCA tubes, not A or B.
> 
> The rig works perfect in every way.  No tube gets hot or red, no hum from
> the transformer cores,  Voice peaks are abt 180watts AM.
> 
> All voltages seem to check with the manual, and resistance measurements are
> ok.
> 
> After abt a 10 to 15 min steady QSO  the caps from the bandswitch start to
> get hot.
> Then after couple of more transmissions the plate current goes to Full scale
> from a max loading of 300 ma.
> There has been no reported changes in signal quality, just nothing.
> After contacts with 3 stations all report gud steady carrier and full audio.
> 
> The radio is NOT grounded, the coax goes outside to a dipole at 40 ft with a
> 1.1:1 SWR at 3795hz and 1.7:1 at 3890hz.
> 
> No apparent damage has been seen anywhere inside the radio, replace the caps
> and away it goes agn.
> 
> This is getting frustrating, in my 40 + years I have never seen anything
> like this.  I have lots of experience with Boat anchor before they were BA
> The rig is in very gud condition, excellent interior, clean, minor mod was
> to remove the clipping circuit from the audio.
> 
> 
> Tnx agn fer all your help,  I'll let you know what I find.
> 
> de Skip     K3CC    ex/K3ZTJ
> 
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