[Boatanchors] Ranger Caps and Solid State Rectifiers

[Bob Sullivan]

Larry,

With all due respect, one needs to look at the old micas! They  
frequently become leaky especially if they see DC (I think this is a  
migration issue). I've replaced so many during troubleshooting that I  
now replace all micas used as coupling caps - just to save grief later.

73, Bob
WØYVA
http://www.isquare.com/personal_pages/ras-hardware.htm

On Oct 13, 2008, at 6:46 PM, BLIMPY wrote:

>
> 1. Yup, those turquoise caps are old plastic molded paper caps.. and  
> like all old paper caps... they have to go !
>
>   Suitable replacements for paper caps are either polyethelene,  
> mylar or polyester.   Some hi-fi purists insist on polyester.  They  
> cost a few cents more.. and for a radio that sounds a good as the  
> ranger why not... but again only for the coupling caps.  Bypass caps  
> needn't be fancy. Use the nice yellow japanese ones sold by Antique  
> Electronics Supply or Radio Daze.
>
>  Old electrolytics must go !.  Leave those mounted on the chassis  
> for cosmetic reasons, but use nice new jap caps underneath.
>
>  Never mess with mica caps !
>
>   Please !  Forget  using solid state rectifiers in tube radios.   
> They will ruin your tubes by stripping the filaments during warm  
> up... and the voltages will all run too high.  Any kind of voltage "  
> sag" was figured into the original design specs by the engineers at  
> Johnson.
>
>   There is no heat problem with a ranger or any of the other  
> commercially made ham AM transmitters, anyway. Don't fix engineering  
> problems that don't exist, is my advice.   If you really want "  
> coolth"   buy a muffin fan.  A 220v muffin fan run on 110v  runs  
> quiet.  put 4 stick on grommet type feet on it.. and go to town.
>
> Larry
> _______________________________________________
>

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