Topband: SB-1000

[Don Lynch]

Also check the contacts on the bandswitch.  I have that amp and have a
similar problem with 160 operation, apparently from burning out one of the
contacts on the switch.  It would be a bear to change out, even if you
could find a replacement, so I just don't run that amp on 160 any more.

Good luck with it.

Vy 73,

Don W4ZYT



On Thu, Dec 17, 2015 at 8:30 PM, Tom W8JI <w8ji at w8ji.com> wrote:

> 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
>> _________________
>>
>
> 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.
>
>
>
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>



-- 
Don Lynch MD W4ZYT - EI2IM, 5Z4ZK
Virginia Beach, Virginia
ARRL - IRTS - ARSK - Virginia DXCC - PVRC
FOC 1700  -  RNARS 4473  -  FISTS 3381  -  CWOPS 55
w4zyt.don at gmail.com
==
Donald F. Lynch, Jr., MD, FACS
Emeritus Professor of Urology
Eastern Virginia School of Medicine
Norfolk, Virginia, USA