[Boatanchors] Globe King 500A tuning

[Richard Knoppow]

----- Original Message ----- 
From: "Charles Ring" <w3nu at roadrunner.com>
To: <boatanchors at mailman.qth.net>; <wrl at mailman.qth.net>
Sent: Monday, September 24, 2012 5:40 AM
Subject: [Boatanchors] Globe King 500A tuning


> After a month of doing fine on 80. 40, and 20 CW, my Globe 
> King won't
> tune properly on 80. On 80, plenty of plate current 
> off-dip, but no
> proper dip at all, with minimum plate current and max 
> output (less than
> 100 watts) at minimum plate tuning capacitance. Works 
> great on 40 with
> 350 watts out and normal tuning. Somewhat degraded on 20 
> but functional.
> This is same on antenna and dummy load.
>
> My prior attempt to use it on 15 failed similarly with 
> very low output
> and red 4-400A plate, but now 80 while 40 does fine? Does 
> this make any
> sense? I have used Deoxit on all switch contacts.
>
> -- 
> *Charles Ring W3NU*

     The schematics for all of the 500 series show a pi 
network output with switchable taps on the coil and a choice 
of caps to put in series with the loading cap.  I would 
check the switch for the coil and also make sure none of the 
taps on the coil is open. Its possible there is a shorted 
turn on the coil but that doesn't seem likely. Also check 
the loading caps, switch and wiring for it.
     Check the switches for burned contacts or open 
connections.
     There are instruction books and schematics for the 500 
series at BAMA under WRL. The 500A book is a PDF, the rest 
are page by page GIF.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com