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Re: Topband: SB-1000

To: "Jim Murray" <adkmurray@yahoo.com>, "TopBand List" <topband@contesting.com>
Subject: Re: Topband: SB-1000
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Thu, 17 Dec 2015 15:30:17 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Just came off 20M, amp working fine. Went to 160 plate and load controls have no control, no output. Plate current climbs high with any added drive (45-50W) and blew both 10amp fuses.Off comes the cover.jimk2hn
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It might be something else, but I would bet the contact on the 160 padding capacitor is burned off. This is what the anti-corona washer reduced. Heath did not use that washer.

It arcs there when the loading cap is too far closed (too much grid current) for the amount of drive on higher bands, or if the antenna should become grossly mismatched when at high power on bands other than 160. The worse band for arcing the 160 padding contact is when on 80 meters.



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