[Amps] SB220 tune cap problem

Bill Turini mailing_lists at hamanuals.com
Thu Jun 11 22:33:34 EDT 2015


Folks

A few weeks ago I was in the heat of the battle in an RTTY contest when 
there was a giant flash and some arcing.  On the way to turning my SB220 
off, I noticed that the power output was north of 1400 watts and perhaps 
I had changed bands without retuning.  No matter....

I opened up the amp and found that the Tune variable capacitor was 
damaged from the arcing.  What didn't surprise me was that the plates 
looked like they had been filed down prior to my buying the amp.  So, 
time for a new cap.

 From browsing the Internet I see that Heath came out with a replacement 
cap that was heavier duty.  This cap is available from RF Parts.  But 
comments on the Internet say that installing the heavier cap just 
transferred the arcing to the bandswitch.

Does anyone have any comments on this?  Is it worthwhile to get the 
replacement cap? Are there any steps that can be taken to protect the 
bandswitch with the new cap?

Thanks,

Bill

-- 
Bill Turini
KA4GAV



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